Details of a Researcher - OKAMURA, Mitsu

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OKAMURA, Mitsu

Scopus Paper Info

Paper Count: 72 Citation Count: 2002 h-index: 24

Click to view the Scopus page. The data was downloaded from Scopus API in June 12, 2025, via http://api.elsevier.com and http://www.scopus.com .

Google Scholar Information (Citations per year)

Citation Count: 3888 h-index: 33 i10-index: 64

Click to view the Google Scholar page.

Scopus Information

Affiliation

Faculty of Science and Engineering, School of Creative Science and Engineering

Job title

Professor

Degree

博士（工学） ( 東京工業大学 )

Mail Address

Homepage URL

https://www.okamura.sci.waseda.ac.jp/

Research Experience

2004.04

-

2025.03

Ehime University
1997

-

2001

建設省土木研究所
1993

-

1997

東京工業大学工学部土木工学科

Education Background

　

-

1993

Tokyo Institute of Technology Science of Engineering Civil Engineering
　

-

1993

Tokyo Institute of Technology Graduate School, Division of Science and Engineering

Committee Memberships

2023.10

-

Now

日本学術会議連携委員
2023.10

-

Now

（公財）鉄道総合技術研究所鉄道土構造物設計標準に関する委員会委員長
2023.01

-

Now

国研土木研究所河川堤防液状化対策マニュアル改定委員会委員長
2022.06

-

Now

国土技術研究センター堤防研究会委員
2022.04

-

Now

リバーフロント研究所高規格堤防の耐震基準検討委員会委員長
2022.04

-

Now

国立研究開発法人土木研究所第5期外部評価委員会委員
2022.04

-

Now

西日本高速道路株式会社四国支社入札監視委員会委員
2022.01

-

Now

International Society of Soil Mechanics Geotechnical Engineering Member of TC221
2021.10

-

Now

国土交通省四国地方整備局吉野川学識者会議委員
2021.04

-

Now

地盤工学会災害調査データの収集と活用委員会委員長
2020.12

-

Now

国土交通省水管理・国土保全局河川堤防の強化に関する技術検討会委員
2020.08

-

Now

JST 創発的研究支援事業外部専門家
2019.07

-

Now

国土交通省水管理・国土保全局河川技術評価委員会委員
2019.01

-

Now

国土交通省水管理・国土保全局河川砂防技術基準検討委員会委員
2018.08

-

Now

International Society of Soil Mechanics and Geotechnical Engineering, Chairman of ATC3
2017.06

-

Now

国土交通省四国地方整備局リバーカウンセラー
2017

-

Now

国土交通省四国地方整備局肱川流域学識者会議
2016.09

-

Now

国土交通省四国地方整備局重信川流域学識者会議
2015.10

-

Now

International Society of Soil Mechanics Geotechnical Engineering Member of TC203
2020.06

-

2025.06

日本建設機械化施工協会四国支部支部長
2017.06

-

2025.03

国土交通省四国地方整備局道路防災有識者
2022.06

-

2024.06

日本工学会理事
2021.06

-

2023.06

土木学会地盤工学委員会委員長
2020.03

-

2023.03

国土技術研究センター河川堤防耐震対策高度化研究会座長
2019.06

-

2021.06

土木学会地盤工学委員会副委員長
2019.06

-

2021.06

Japanese Geotechnical Society Vice President
2019.06

-

2021.06

地盤工学会副会長
2019.04

-

2021.03

土木学会土木技術者資格委員会上級土木技術者資格小委員会主査
2019.04

-

2021.03

土木学会土木技術者資格委員会特別上級土木技術者資格小委員会主査
2016.06

-

2021.03

国土交通省四国地方整備局事業評価監視委員会委員
2015.09

-

2020.12

日本学術振興会科学研究費委員会専門委員
2020.01

-

2020.06

国土交通省水管理・国土保全局令和元年台風第19号の被災を踏まえた河川堤防に関する技術検討会委員
2019.08

-

　

United Nations International expart panel for Palu Liquefaction Research Center
2017.06

-

2019.07

地盤工学会 Soils and Foundations 副委員長
2016.08

-

2019.04

The Asian Civil Engineering Coordinating Council Chairman, Planning Committee Meeting
2016.08

-

2019.04

アジア土木学協会連合企画委員会委員長
2016.06

-

2019.04

The Asian Civil Engineering Coordinating Council, Executive Committee Meeting Member
2016.06

-

2019.04

The Asian Civil Engineering Coordinating Council, Chair of Planning Committee Meeting
2018.11

-

2019.03

国土交通省水管理・国土保全局河川砂防技術基準設計編（河川堤防，護岸・水制）改定に向けた技術小委員会委員
2011.04

-

2018.03

国土交通省堤防技術研究会委員
2016.04

-

2017.04

地盤工学会四国支部支部長
2016.05

-

2017.03

国土交通省四国地方整備局緑川・白川堤防調査委員会委員
2015.09

-

2016.04

2015年関東・東北豪雨災害土木学会・地盤工学会合同調査団副団長
2015.05

-

2016.04

土木研究所河川堤防の液状化対策の手引き策定委員会委員長

▼display all

Research Areas

Geotechnical engineering

Research Interests

支持力
基礎の耐震設計
液状化対策
液状化
bearing capacity
aseismic design
liquefaction countermeasure
Soil liquefaction

▼display all

Awards

Best paper award

2025.06 Japanese Geotechnical Society Centrifuge modeling of scale effect on hydraulic gradient of backward erosion piping in uniform aquifer under river levees

Winner： Mitsu Okamura, Yusuke Tsuyuguchi, Norihiro Izumi, Kennichi Maeda
事業企画賞「四国地域の地震防災研究」

2021.06 地盤工学会
事業企画賞「河川堤防」

2021.06 地盤工学会
2020 Associate Editor Award, Soils and Foundations

2021.06 Japanese Geotechnical Society

Winner： Mitsu Okamura
河川技術論文賞

2018.06 土木学会水工学委員会高水時の堤防裏法面の滑り領域と破堤危険度評価

Winner：岡村未対
distinguished service award

2014.06 Japanese Geotechnical Society

Winner： OKAMURA Mitsu
Best paper award in the Japanese geotechnical Engineering jounal

2013.06 Japanese Geotechnical Society

Winner： OKAMURA Mitsu
Best paper award

2012.06 Japanese Geotechnical Society

Winner： OKAMURA Mitsu
Best Paper Award ISGI09

2009
地盤工学会四国支部技術開発賞

2009
Best Paper Award ISGI09

2009
地盤工学会四国支部賞（研究・論文）

2008
2006 SHAMSHER PRAKASH RESEARCH AWARD

2007
2006 SHAMSHER PRAKASH RESEARCH AWARD

2007
研究奨励賞

1998

▼display all

Papers

Effectiveness of sheet pile enclosure with drainage ability as liquefaction countermeasure for river levees

Mitsu Okamura, Mizuki Suyama, Kohei Ono

Soils and Foundations 65 ( 1 ) 101564 - 101564 2025.02

DOI

Scopus
Effects of Providing Drainage Ability to Sheet Piles on Settlement Reduction of Embankment Resting on Liquefiable Sand

Mizuki SUYAMA, Mitsu OKAMURA, Kohei ONO

Journal of Japan Association for Earthquake Engineering 25 ( 5 ) 5_13 - 5_22 2025

DOI
Stability of sheet-pile wall in liquefiable soil: LEAP-2020 and LEAP-2022 centrifuge tests at Ehime University

Kohei Ono, Mitsu Okamura

Soil Dynamics and Earthquake Engineering 182 108743 - 108743 2024.07

DOI

Scopus

2

Citation

(Scopus)
Correlation of CPT measurements and relative density of LEAP-2017 and LEAP-2020 centrifuge models

Alejandro Sepulveda, Mourad Zeghal, Bruce L. Kutter, Majid T. Manzari, Tarek Abdoun, Sandra Escoffier, Stuart K. Haigh, Wen-Yi Hung, Evangelia Korre, Gopal S.P. Madabhushi, Satish Manandhar, Mitsu Okamura, Tetsuo Tobita, Kyohei Ueda, Yan-Guo Zhou

Soil Dynamics and Earthquake Engineering 181 108639 - 108639 2024.06

DOI

Scopus

3

Citation

(Scopus)
LEAP-ASIA-2019: Summary of Centrifuge Experiments on Liquefaction-Induced Lateral Spreading – Application of the Generalized Scaling Law

Tetsuo Tobita, Koji Ichii, Kyohei Ueda, Ryosuke Uzuoka, Ruben R. Vargas, Mitsu Okamura, Asri Nurani Sjafruddin, Jiro Takemura, Lyu Hang, Susumu Iai, Jad Boksmati, Alessandro Fusco, Samy Torres-Garcia, Stuart Haigh, Gopal Madabhushi, Majid Manzari, Sandra Escoffier, Zheng Li, Dong Soo Kim, Satish Manandhar, Wen-Yi Hung, Jun-Xue Huang, Truong-Nhat-Phuong Pham, Mourad Zeghal, Tarek Abdoun, Evangelia Korre, Bruce L. Kutter, Trevor J. Carey, Nicholas Stone, Yan-Guo Zhou, Kai Liu, Qiang Ma

Model Tests and Numerical Simulations of Liquefaction and Lateral Spreading II 3 - 34 2024.02

　View Summary

Abstract

In the framework of Liquefaction Experiments and Analysis Projects (LEAP), round-robin centrifuge model tests were conducted in collaboration with ten international institutes on identical saturated sloping sand layers with a wide range of initial conditions. Two tests, one with a model following conventional centrifuge scaling law and the other with a model following the generalized scaling law (GSL), were assigned to each institute for two purposes: (1) validation of the generalized scaling law (GSL) and (2) development of additional experimental data sets to fill the gaps in the existing experimental data sets. The GSL may be validated when the ground deformation is small (less than 250 mm in the present study). The trend surface was updated with the new data sets, whose trend is consistent with the previous one.

DOI

Scopus

1

Citation

(Scopus)
Evaluation of Liquefaction Strength of Sand and Effect of Partial Drainage Using Pore Pressure Generation Model

Kohei ONO, Daijiro OKA, Mitsu OKAMURA

Journal of Japan Association for Earthquake Engineering 24 ( 4 ) 4_109 - 4_118 2024

DOI
Pore Pressure Generation of Liquefiable Soil Subjected to Irregular Cyclic Loading

Asri Nurani Sjafruddin, Mitsu Okamura, Kohei Ono

Japanese Geotechnical Society Special Publication 10 ( 59 ) 2320 - 2325 2024

DOI
Centrifuge modeling of liquefiable sand supported by sheet pile wall: LEAP tests at Ehime University

Kohei Ono, Mitsu Okamura

Japanese Geotechnical Society Special Publication 10 ( 7 ) 139 - 143 2024

DOI
Assessment of liquefaction potential and applicability of excess pore pressure generation model for gravelly soil

Kohei Ono, Mitsu Okamura

Japanese Geotechnical Society Special Publication 10 ( 17 ) 576 - 579 2024

DOI
Centrifuge modeling of scale effect on hydraulic gradient of backward erosion piping in uniform aquifer under river levees

Mitsu Okamura, Yusuke Tsuyuguchi, Norihiro Izumi, Kenichi Maeda

Soils and Foundations 62 ( 5 ) 101214 2022.10 [Refereed]

Authorship：Lead author, Corresponding author

DOI

Scopus

9

Citation

(Scopus)
Centrifuge modelling of rainfall infiltration affected by rainfall;soil characteristics

Kohei Ono, Ryota Saeki, Mitsu Okamura

Proc. 10th International Conference on Physical Modelling in Geotechnics 2022.09 [Refereed]
Centrifuge tests on the scale effect on hydraulic gradient of backward erosion piping

Mitsu Okamura, Yusuke Tsuyuguchi, Kohei Ono

Proc. 10th International Conference on Physical Modelling in Geotechnics 2022.09

Authorship：Lead author, Corresponding author
Insight into excess pore pressure generation leading to liquefaction of sand with stress history under saturated and unsaturated conditions

Mitsu Okamura

Soils and Foundations 62 ( 4 ) 101187 2022.08 [Refereed]

Authorship：Lead author, Corresponding author

DOI

Scopus

6

Citation

(Scopus)
Dynamic Behavior of Pipe Bend Subjected to Thrust Force Buried in Liquefiable Sand

Kohei Ono, Mitsu Okamura

Proc. International Conference on Performance Based Design in Earthquake Geotechnical Engineering 2022.07
Factors affecting liquefaction resistance and assessment by pore pressure model

Mitsu Okamura

Proc. International Conference on Performance Based Design in Earthquake Geotechnical Engineering 2022.07 [Refereed] [Invited]

Authorship：Lead author, Corresponding author
LEAP-ASIA-2019: Validation of centrifuge experiments and the generalized scaling law on liquefaction-induced lateral spreading

Tobita, Tetsuo, Ueda, Kyohei, Vargas, Ruben R, Ichii, Koji, Okamura, Mitsu, Sjafruddin, Asri Nurani, Takemura, Jiro, Hang, Lyu, Uzuoka, Ryosuke, Iai, Susumu, Boksmati, Jad, Fusco, Alessandro, Torres-Garcia, Samy, Haigh, Stuart, Madabhushi, Gopal, Manzari, Majid, Escoffier, Sandra, Li, Zheng, Kim, Dong Soo, Manandhar, Satish, Hung, Wen-Yi, Huang, Jun-Xue, Pham, Truong-Nhat-Phuong, Zeghal, Mourad, Abdoun, Tarek, Korre, Evangelia, Kutter, Bruce L, Carey, Trevor J, Stone, Nicholasm, Zhou, Yan-Guo, Liu, Kai, Ma, Qiang

Soil Dynamics and Earthquake Engineering 157 107237 2022.04 [Refereed]
Valiadtion and limitation of the generalized scaling law through multi-institutional collaboration

Tetsuo Tobita, Kyohei Ueda, Ruben Vargas, Ryosuke Uzuoka, Koji Ichii, Mitsu Okamura, Asri Sjafruddin, Jiro Takemura, Lyu Hang, Susumu Iai, Boksmati Jad. Fusco Alessandro, Torres-Garcia Samy, Haigh Stuart, Madabhushi, Manzari Majid, Escoffier Sandra, Zheng Li, Kim Dong Soo, Manandhar Satish, Hung Wen-Yi, Huang Jun-Xue, Pham Truong-Nhat-Phuong, Zeghal Mourad, Abdoun Tarek, Korre Evangelia, Kutter Bruce, Carey Trevor, Stone Nicholas, Zhou Yan-Guo, Liu Kai, Ma Qiang

Proc Asian Conf. on Physical Modelling in Geotechnics (Asiafuge 2021) 1 2021.11 [Refereed]
Verification of effectiveness and design procedure of gravel drains for liquefaction remediation

Utari S. Minaka, Mitsu Okamura, Kohei Ono

SOILS AND FOUNDATIONS 61 ( 5 ) 1191 - 1206 2021.10 [Refereed]

Authorship：Corresponding author

DOI
Resonance effect on shaking of tall buildings in Kathmandu Valley during the 2015 Gorkha earthquake in Nepal

Netra Prakash Bhandary, Youb Raj Paudyal, Mitsu Okamura

Environmental Earth Sciences 80 ( 13 ) 2021.07 [Refereed]

DOI

Scopus

5

Citation

(Scopus)
2018年7月高水で肱川堤防に生じたパイピングの進展度調査

岡村未対, 陣内尚子, 小野哲治, 大薮剛士

土木学会論文集C 76 ( 4 ) 363 - 373 2020.12 [Refereed]

Authorship：Lead author
SEEPAGE FLOW ANALYSIS OF DOUBLE LAYER FOUNDATION AROUND A RIVER LEVEE WITH THE USE OF A SIMPLE MATHEMATICAL MODEL

泉典洋, 前田健一, 岡村未対

土木学会論文集 B1(水工学)(Web) 76 ( 2 ) I_325 - I_330 2020.12 [Refereed]

Authorship：Last author

J-GLOBAL
Comparison of the Type-B Numerical Simulations with Centrifuge Test Results

Majid T. ManzariEmail authorMohamed El GhoraibyMourad ZeghalBruce L. KutterPedro ArduinoAndres R. BarreroEmilio BilottaLong ChenRenren ChenAnna ChiaradonnaAhmed ElgamalGianluca FasanoKiyoshi FukutakeWilliam FuentesAlborz GhofraniStuart, K. HaighWen-Yi HungKoji IchiiDong Soo KimTakatoshi KiriyamaCarlos LascarroGopal S, P. MadabhushiVicente MercadoJack MontgomeryMitsu OkamuraOsamu OzutsumiZhijian, QiuMahdi TaiebatTetsuo TobitaThaleia TravasarouDimitra, TsiaousiKyohei UedaJose UgaldeToma, WadaRui WangMing, YangJian-Min ZhangYan-Guo ZhouKaterina Ziotopoulou

Model Tests and Numerical Simulations of Liquefaction and Lateral Spreading 187 - 218 2020.11

DOI

Scopus

19

Citation

(Scopus)
堤体表面形状に基づく河川堤防のパイピング進行度評価

岡村未対

AI・データサイエンス論文集 1 ( J1 ) 429 - 436 2020.11 [Refereed]

Authorship：Lead author, Corresponding author
Difference and Sensitivity Analyses of the LEAP-2017 Experiments

Nithyagopal GoswamiMourad, ZeghalEmail authorBruce L, KutterMajid, T. ManzariTarek AbdounTrevor CareyYun-Min ChenSandra EscoffierStuart, K. HaighWen-Yi HungDong-Soo KimSeong-Nam KimEvangelia KorreTing-Wei LiaoKai LiuGopal S, P. MadabhushiSrikanth, S. C. Madabhushi, Mitsu Okamura, Asri Nurani, SjafruddinTetsuo TobitaKyohei, UedaRuben VargasYan-Guo Zhou

Model Tests and Numerical Simulations of Liquefaction and Lateral Spreading 131 - 151 2020.10 [Refereed]

DOI

Scopus

3

Citation

(Scopus)
Investigation of damage mechanism of large-scale landslide in Sibalaya, Palu due to the 2018 Sulawesi Earthquake

K. Ono, M. Okamura, A. Maulana, A. Arysad, S. Nurdin

Proc. 17th World Conf. on Earthquake Engineering 2020.10 [Refereed]
Large-scale flowslide in Sibalaya caused by the 2018 Sulawesi earthquake

Mitsu Okamura, Kohei Ono, Ardy Arsyad, Utari S. Minaka, Sukiman Nurdin

Soils and Foundations 60 ( 4 ) 1050 - 1063 2020.08 [Refereed]

Authorship：Lead author, Corresponding author

DOI

Scopus

30

Citation

(Scopus)
Large flowslide mechanism in Sibalaya caused by the 2018 Sulawesi Earthquake

Mitsu Okamura, Kohei Ono, Ardy Arsyad

1st Int. Symposium on Construction Resources for Environmentally Sustainable Technologies (CREST 2021) 2020.03 [Refereed]

Authorship：Lead author, Corresponding author
LeAP-Asia-2019: Validation of centrifuge experiments and generalized scaling law onliquefaction-induced lateral spreading

Tetsuo Tobita, K. Ichii, M. Okamura, A. N. Sjafruddin, J. Takemura, L. Hang, K. Ueda, R. Uzuoka, R. R. Vargas, J. Boksmati, A. Fusco, S. Torres-Garcia, S. Haigh, G. Madabhushi, M. Manzari, S. Escoffier, Z. Li, D. S. Kim, S. Manandhar, W. Y. Hung, J. X. Huang, T. N.P. Pham, M. Zeghal, T. Abdoun, E. Korre, B. L. Kutter, T. J. Carey, N. Stone, Y. G. Zhou, K. Liu, Q. Ma

16th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2019 1 2020 [Refereed]

DOI

Scopus

14

Citation

(Scopus)
LEAP-UCD-2017 Comparison of Centrifuge Test Results

Bruce L. Kutter, Trevor J. Carey, Nicholas Stone, Bao Li Zheng, Andreas Gavras, Majid T. Manzari, Mourad Zeghal, Tarek Abdoun, Evangelia Korre, Sandra Escoffier, Stuart K. Haigh, Gopal S.P. Madabhushi, Srikanth S.C. Madabhushi, Wen Yi Hung, Ting Wei Liao, Dong Soo Kim, Seong Nam Kim, Jeong Gon Ha, Nam Ryong Kim, Mitsu Okamura, Asri Nurani Sjafruddin, Tetsuo Tobita, Kyohei Ueda, Ruben Vargas, Yan Guo Zhou, Kai Liu

Model Tests and Numerical Simulations of Liquefaction and Lateral Spreading - LEAP-UCD-2017 69 - 103 2020

DOI

Scopus

23

Citation

(Scopus)
LEAP-2017 Centrifuge Test at Ehime University

Mitsu Okamura, Asri Nurani Sjafruddin

Model Tests and Numerical Simulations of Liquefaction and Lateral Spreading - LEAP-UCD-2017 277 - 291 2020

DOI

Scopus

1

Citation

(Scopus)
LEAP-UCD-2017 V. 1.01 Model Specifications

Bruce L. Kutter, Trevor J. Carey, Nicholas Stone, Masoud Hajialilue Bonab, Majid T. Manzari, Mourad Zeghal, Sandra Escoffier, Stuart K. Haigh, Gopal S.P. Madabhushi, Wen Yi Hung, Dong Soo Kim, Nam Ryong Kim, Mitsu Okamura, Tetsuo Tobita, Kyohei Ueda, Yan Guo Zhou

Model Tests and Numerical Simulations of Liquefaction and Lateral Spreading - LEAP-UCD-2017 3 - 29 2020

DOI

Scopus

24

Citation

(Scopus)
A study on shaking of tall buildings in Kathmandu Valley during the 2015 Nepal Earthquake

Netra P Bhandary, Mitsu Okamura, Youb R. Paudyal

Proc. 16th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering 1 2019.10 [Refereed]
Influence of strain histories on liquefaction resistance of sand

Fred Nelson, Mitsu Okamura

Soils and Foundations 59 ( 5 ) 1481 - 1495 2019.10 [Refereed]

Authorship：Corresponding author

DOI

Scopus

19

Citation

(Scopus)
北川で繰返し発生した噴砂による堤内・裏法尻箇所のゆるみ調査

前田健一, 岡村未対, 石原雅規, 新清晃, 上野俊幸, 西村柾哉, 高辻理人, 品川俊介, 笹岡信吾

河川技術論文集 25 535 - 540 2019.06 [Refereed]

Authorship：Lead author
北川で繰返し発生した陥没を伴う噴砂の詳細メカニズム調査

岡村未対, 前田健一, 西村柾哉, 高辻理人, 石原雅規, 品川俊介, 今村衛

河川技術論文集 25 487 - 492 2019.06 [Refereed]

Authorship：Lead author
Centrifuge modeling on lateral force-displacement behavior of buried pipes in liquefied sand

K. Ono, M. Okamura

Proc. 7th Int. Conf. on Earthquake Geotechnical Engineering 1 418 - 425 2019.06 [Refereed]
Effectiveness of vertical drains to prevent occurrence of liquefaction and settlement

M. Okamura, U.S. Minaka, K. Ono

Proc. 7th Int. Conf. on Earthquake Geotechnical Engineering 1 477 - 490 2019.06 [Refereed] [Invited]

Authorship：Lead author
空気注入不飽和化工法(Air‐des工法)の技術的進展

藤井直, 浅田英幸, 矢部浩史, 山浦昌之, 岡村未対

地盤工学会誌 67 ( 1 ) 32‐33 2019.01

J-GLOBAL
Dynamic Centrifuge Tests on Dissipation Effects of Excess Pore Water Pressure by Gravel Drains

ONO Kohei, MINAKA Utari Sriwijaya, OKAMURA Mitsu

Journal of Japan Association for Earthquake Engineering 19 ( 6 ) 6_68 - 6_75 2019 [Refereed]

　View Summary

The installation of gravel drains is one of the liquefaction countermeasures that has been used extensively. However, there are not many experimental studies that verified its effectiveness in a realistic stress level, and uncertainties still remains that has not been studied sufficiently. In a present study, a series of centrifuge tests were conducted focusing on the influence of permeability of drains and liquefaction layer and the effective confining pressure on the dissipation effects of excess pore water pressure by gravel drains. The experimental results showed that the higher the permeability of the liquefaction layer, the higher the dissipation effect by gravel drains. In addition, gravel drains effectively prevented liquefaction at a greater depth as compared with at shallower depth. On the other hand, the duration of liquefaction was significantly shortened even when the permeability was low and drains could not suppress the occurrence of liquefaction.

DOI CiNii
Small-strain shear modulus and liquefaction resistance of sand with carbonate precipitation

Simatupang Minson, Okamura Mitsu, Hayashi Kazuyuki, Yasuhara Hideaki

SOIL DYNAMICS AND EARTHQUAKE ENGINEERING 115 710 - 718 2018.12 [Refereed]

DOI

Scopus

52

Citation

(Scopus)
液状化層の透水性がグラベルドレーンの間隙水圧消散効果に与える影響

小野耕平, UTARI Sriwijaya Minaka, 岡村未対

日本地震工学シンポジウム論文集(CD-ROM) 15th ROMBUNNO.GO12‐01‐09 2018.11 [Refereed]

J-GLOBAL
Internal erosion in a foundation soil under a sand levee and its manifestation on the levee surface

M. Okamura, M. Imamura, N. Jinnouchi

Scour and Erosion IX - Proceedings of the 9th International Conference on Scour and Erosion, ICSE 2018 471 - 476 2018.10

Authorship：Lead author, Corresponding author
Reduction in Liquefaction induced settlement of river levee by enhancing horizontal stress with sheet piles

Okamura, M, Inoue, T, Jin-nouchi, N, Ono, K

Proceedings of the 1st International Conference of Press-in Engineering 243 - 248 2018.09 [Refereed]
堤体表面沈下分布と貫入試験によるパイピング緩み領域の把握

岡村未対, 今村衛, 陣内尚子, 小野耕平, 山本卓夫, 鎌田卓

河川技術論文集 24 529 - 534 2018.06 [Refereed]

Authorship：Lead author
A new shared miniature cone penetrometer for centrifuge testing

T. Carey, A. Gavras, B. Kutter, S. K. Haigh, S. P.G. Madabhushi, M. Okamura, D. S. Kim, K. Ueda, W. Y. Hung, Y. G. Zhou, K. Liu, Y. M. Chen, M. Zeghal, T. Abdoun, S. Escoffier, M. Manzari

Physical Modelling in Geotechnics 1 293 - 298 2018 [Refereed]

DOI

Scopus

33

Citation

(Scopus)
LIQUEFACTION MITIGATION EFFICIENCY OF SAND IMPROVED WITH CALCIUM CARBONATE PRECIPITATED UNDER VARIOUS DEGREES OF SATURATION

HAYASHI Kazuyuki, OKAMURA Mitsu, YASUHARA Hideaki, SIMATUPANG Minson

Journal of Japan Society of Civil Engineers, Ser. C (Geosphere Engineering) 74 ( 2 ) 164 - 176 2018 [Refereed]

　View Summary

 It is pointed out that the shear strength of cemented soil improved with calcium carbonate (CaCO₃) crystal is enhanced by decrease in saturation degree during precipitation. In this study, improvement efficiency of liquefaction resistance enhanced through controlling saturation degree (from 20 to 100%) and CaCO₃ content (from 0 to 1%) was investigated by undrained cyclic triaxial tests for coarse and fine sand specimens. Enzymatically Mediated Calcite Precipitation (EMCP) technique was employed to precipitate CaCO₃. SEM-EDX was utilized to observe calcium carbonate crystal on the sand grain surface and to identify the crystal. It was found that, in EMCP with controlling saturation degree during precipitation, high efficiency in liquefaction mitigation was provided to finer sand including larger crystal.

DOI CiNii J-GLOBAL
Pre-shaking effects on volumetric strain and cyclic strength of sand and comparison to unsaturated soils

Mitsu Okamura, Fred Nelson, Shota Watanabe

Soil Dynamics and Earthquake Engineering 124 307 - 316 2018 [Refereed]

Authorship：Lead author, Corresponding author

DOI

Scopus

16

Citation

(Scopus)
Twenty-Four Centrifuge Tests to Quantify Sensitivity of Lateral Spreading to Dr and PGA

Bruce L. Kutter, Trevor J. Carey, Bao Li Zheng, Andreas Gavras, Nicholas Stone, Mourad Zeghal, Tarek Abdoun, Evangelia Korre, Majid Manzari, Gopal S.P. Madabhushi, Stuart Haigh, Srikanth S.C. Madabhushi, Mitsu Okamura, Asri Nurani Sjafuddin, Sandra Escoffier, Dong Soo Kim, Seong Nam Kim, Jeong Gon Ha, Tetsuo Tobita, Hikaru Yatsugi, Kyohei Ueda, Ruben R. Vargas, Wen Yi Hung, Ting Wei Liao, Yan Guo Zhou, Kai Liu

Geotechnical Special Publication 2018-June ( GSP 293 ) 383 - 393 2018 [Refereed]

DOI

Scopus

23

Citation

(Scopus)
Liquefaction resistance of sand remediated with carbonate precipitation at different degrees of saturation during curing

Minson Simatupang, Mitsu Okamura

SOILS AND FOUNDATIONS 57 ( 4 ) 619 - 631 2017.08 [Refereed]

DOI

Scopus

85

Citation

(Scopus)
パイピングにより堤体表面に現れる沈下分布の特徴

岡村未対, 平尾優太郎, 前田健一

河川技術論文集 23 399 - 404 2017.06 [Refereed]

J-GLOBAL
高水時の堤防裏法面の滑り領域と破堤危険度評価

岡村未対, 小阪佳平

河川技術論文集 23 393 - 398 2017.06 [Refereed]

J-GLOBAL
Full scale test on cost effective liquefaction countermeasure for a highway embankment

Mitsu Okamura

Journal of Seismological Research 40 ( 1 ) 45 - 51 2017 [Refereed]
Numerical simulation of centrifuge tests to evaluate the performance of desaturation by air injection on liquefiable foundation soil of light structures

Narayan Prasad Marasini, Mitsu Okamura

SOILS AND FOUNDATIONS 55 ( 6 ) 1388 - 1399 2015.12 [Refereed]

DOI J-GLOBAL

Scopus

28

Citation

(Scopus)
Report on a reconnaissance survey of damage in Kathmandu caused by the 2015 Gorkha Nepal earthquake

Mitsu Okamura, Netra P. Bhandary, Shinichiro Mori, Narayan Marasini, Hemanta Hazarika

SOILS AND FOUNDATIONS 55 ( 5 ) 1015 - 1029 2015.10 [Refereed]

DOI J-GLOBAL

Scopus

44

Citation

(Scopus)
Air injection to mitigate liquefaction under light structures

Narayan Prasad Marasini, Mitsu Okamura

INTERNATIONAL JOURNAL OF PHYSICAL MODELLING IN GEOTECHNICS 15 ( 3 ) 129 - 140 2015.09 [Refereed]

DOI J-GLOBAL

Scopus

25

Citation

(Scopus)
Numerical simulation of centrifuge tests on seismic behavior of residential building on liquefiable foundation soil

Narayan Marasini, Mitsu Okamura

Computer Methods and Recent Advances in Geomechanics 847 - 852 2015 [Refereed]

DOI

Scopus

2

Citation

(Scopus)
Damage to river levees by the 2011 Off the Pacific Coast Tohoku earthquake and prediction of liquefaction in levees

M. Okamura, S. Hayashi

Geotechnics for Catastrophic Flooding Events - Proceedings of the 4th International Conference on Geotechnical Engineering for Disaster Mitigation and Rehabilation, GEDMAR 2014 57 - 67 2015.01

DOI

Scopus

4

Citation

(Scopus)
薄い砂層の液状化判定法に関する研究

岡村未対, 林秀太郎

日本地震工学シンポジウム論文集(CD-ROM) 14 2014.11 [Refereed]

J-GLOBAL
小型遠心模型実験装置

岡村未対

地盤工学会誌 62 ( 9 ) 4 - 7 2014.09 [Refereed]

J-GLOBAL
Compact Geotechnical Centrifuge Facility

Okamura Mitsu

地盤工学会誌 62 ( 9 ) 4 - 7 2014.09

CiNii
Effects of desaturation as a liquefaction countermeasure for existing embankments

TOMIDA Yuichi, KAMIDA Naomitsu, UCHIDA Junji, OKAMOTO Tatsuya, OKAMURA Mitsu

Japanese Geotechnical Journal 9 ( 3 ) 375 - 386 2014

　View Summary

Highways in Japan have played important roles as emergency traffic routes after earthquakes. Although highway embankments often damaged due mostly to soil liquefaction or related phenomena, however, any liquefaction countermeasure is not implemented. This is largely due to the fact that damaged embankments had been fixed in relatively short time. But this may not be the case if huge earthquake such as the Nankai earthquake occur. In this study, an innovative liquefaction countermeasure technique, desaturation by air injection, is focused on which is inexpensive and applicable to foundation soil below existing structures. Effectiveness of the technique to embankments on liquefiable soils were studied through a series of centrifuge tests. Three models were tested including the benchmark model without desaturated zone and two models with partly saturated foundation soils. In the later models, fully saturated foundation soils were prepared first and air was injected in flight. The resultant degree of saturation in the desaturated zones after the air injection was halted was some 88%. All the models were horizontally shaken at 40g field and model responses were observed in detail. The foundation soil of the benchmark model was liquefied during shaking and embankment crest settled as much as about 20% of the embankment height. While for desaturated model, observed excess pore pressures in the desaturated zones were considerably low and significant reduction in crest settlement was observed. In this study an attempt was made to simulate the centrifuge models using a numerical code, ALID. In the simulation, liquefaction resistances of sand in the desaturated zone were estimated based on the formula proposed by Okamura and Soga (2006). In addition, influence of ridged boundary imposed by the rigid container side walls were taken into account. The simulations captured fairly well the overall figure of experimental observations that crest settlement and deformation of foundation soil decrease with increasing the width of desaturated zone.

DOI CiNii J-GLOBAL
Seismic stability of embankments subjected to pre-deformation due to foundation consolidation

Mitsu Okamura, Shuji Tamamura, Rikuto Yamamoto

Soils and Foundations 53 ( 1 ) 11 - 22 2013 [Refereed]

DOI J-GLOBAL

Scopus

31

Citation

(Scopus)
Experiments and predictions of physical properties of sand cemented by enzymatically-induced carbonate precipitation

Hideaki Yasuhara, Debendra Neupane, Kazuyuki Hayashi, Mitsu Okamura

SOILS AND FOUNDATIONS 52 ( 3 ) 539 - 549 2012.06 [Refereed]

DOI

Scopus

308

Citation

(Scopus)
新しい液状化対策技術―空気注入不飽和化工法(Air‐Des工法)―

岡村未対

地盤工学会誌 60 ( 5 ) 12 - 15 2012.05 [Refereed]

J-GLOBAL
Preparation of fully saturated models for liquefaction study

Mitsu Okamura, Toshiyuki Inoue

INTERNATIONAL JOURNAL OF PHYSICAL MODELLING IN GEOTECHNICS 12 ( 1 ) 39 - 46 2012 [Refereed]

DOI

Scopus

65

Citation

(Scopus)
Damages to River Dikes Due to Tsunami in South-central Coastal Area of Iwate Prefecture in 2011 off the Pacific Coast of Tohoku Earthquake

HARA Tadashi, OKAMURA Mitsu, UZUOKA Ryosuke, ISHIHARA Yukihiro, UENO Katsutoshi

Japanese Geotechnical Journal 7 ( 1 ) 253 - 264 2012 [Refereed]

　View Summary

Numbers of river dikes were damaged by the earthquake motion and tsunami in 2011 off the Pacific Coast of Tohoku Earthquake. This paper summarizes the damages on river dikes in middle and southern coastal part of Iwate Prefecture, with the intention of obtaining physical properties of embankment materials to mitigate the damage on river dikes due to tsunami. Damage configurations such as erosion and collapse were investigated along some rivers in the region of tsunami run up from the estuary. The spots, shapes, soil materials and the damage configurations of the river dikes are highlighted. Damages on embankments at the crossing with road bridges or railway bridges were also surveyed. These investigations have revealed that the river dikes protected with concrete facings will suffer less damage, and that even the three-face-armored banks will be subject to erosion in the upstream of the structures such as abutment or water gate.

DOI CiNii J-GLOBAL
Damages in South-central Coastal Area of Iwate Prefecture in 2011 off the Pacific Coast of Tohoku Earthquake

HARA Tadashi, OKAWARA Masafumi, OSUMI Tsuneo, YAMANAKA Minoru, ISHIHARA Yukihiro, TSUNEKAWA Yoshihiro, OKAMURA Mitsu, UZUOKA Ryosuke

Japanese Geotechnical Journal 7 ( 1 ) 25 - 36 2012

　View Summary

Widespread geotechnical damages were caused in eastern Japan by the earthquake motion and tsunami in 2011 off the Pacific Coast of Tohoku Earthquake. Large tsunami attacked the coastal area of eastern Japan and caused damages to buildings, breakwaters, tide embankments and river levees. The joint reconnaissance team of Tohoku and Shikoku branches of Japanese Geotechnical Society investigated the geotechnical damages in south-central coastal area of Iwate Prefecture at the beginning of April and June. This report summarizes the geotechnical hazards and the damages of port structures, roads, railways, river levees and buildings caused by the earthquake motion and tsunami in 2011 off the Pacific Coast of Tohoku Earthquake in south-central coastal area of Iwate Prefecture.

DOI CiNii J-GLOBAL
Comparison of Liquefaction Features Observed during the 2010 and 2011 Canterbury Earthquakes

R. P. Orense, T. Kiyota, S. Yamada, M. Cubrinovski, Y. Hosono, M. Okamura, S. Yasuda

SEISMOLOGICAL RESEARCH LETTERS 82 ( 6 ) 905 - 918 2011.11

DOI

Scopus

70

Citation

(Scopus)
Visit of ATC3 Committee to Slope Instability Sites in Bhutan

Towhata, I, Okamura, M, Toyota, H

ISSMGE News Bulletins 5 ( 5 ) 20 - 31 2011.10
In-Situ Desaturation Test by Air Injection and Its Evaluation through Field Monitoring and Multiphase Flow Simulation

Mitsu Okamura, Masaya Takebayashi, Katsuji Nishida, Nao Fujii, Motoharu Jinguji, Takehiko Imasato, Hideaki Yasuhara, Emiko Nakagawa

JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING 137 ( 7 ) 643 - 652 2011.07 [Refereed]

DOI

Scopus

131

Citation

(Scopus)
Evolution in mechanical and hydraulic properties of calcite-cemented sand mediated by biocatalyst

H. Yasuhara, K. Hayashi, M. Okamura

Geotechnical Special Publication ( 211 ) 3984 - 3992 2011

DOI

Scopus

59

Citation

(Scopus)
Seismic stability of embankment on soft soil deposit

Mitsu Okamura, Shuji Tamamura

INTERNATIONAL JOURNAL OF PHYSICAL MODELLING IN GEOTECHNICS 11 ( 2 ) 50 - 57 2011 [Refereed]

DOI

Scopus

17

Citation

(Scopus)
2010年チリMaule地震による地盤関連の被害

安田進, 小長井一男, 菅野高弘, 岡村未対, 飛田哲男

日本地震工学シンポジウム論文集(CD-ROM) 13th ROMBUNNO.OS7-FRI-AM(OS7)-3 2010.11

J-GLOBAL
Reconnaissance Report on the Damage Caused by the 2010 Maule, Chile Earthquake

安田進, 小長井一男, 菅野高弘, 岡村未対, 飛田哲男

地盤工学会誌 58 ( 8 ) 42 - 43 2010.08

CiNii
IN-SITU TEST ON DESATURATION BY AIR INJECTION AND ITS MONITORING

Mitsu Okamura, Masaya Takebayashi, Katsuji Nishida, Nao Fujii, Motoharu Jinguji, Takehiko Imasato, Hideaki Yasuhara, Emiko Nakagawa

GROUND IMPROVEMENT TECHNOLOGIES AND CASE HISTORIES ( 1 ) 151 - 158 2010 [Refereed]

DOI

Scopus

1

Citation

(Scopus)
Basic procedures for performance-based design of earth structures considering effects of soil liquefaction

International Conference on Performance-based design in earthquake geotechnical engineering ( 1 ) 1713 - 1718 2010
In-situ air injection as liquefaction countermeasure and its evaluation by multiphase flow simulation

Proceedings 7th International Conference on Urban Earthquake Engineering (7CUEE) & 5th International Conference on Earthquake Engineering (5ICEE) (CD-ROM) ( 1 ) 2010
Effects of calcite precipitation on liquefaction resistance of sand

Proceedings 7th International Conference on Urban Earthquake Engineering (7CUEE) & 5th International Conference on Earthquake Engineering (5ICEE) (CD-ROM) ( 1 ) 2010
Preparation of fully saturated model ground

M. Okamura, T. Inoue

PHYSICAL MODELLING IN GEOTECHNICS, VOLS. 1 AND 2 1 ( 1 ) 147 - 152 2010

DOI

Scopus

11

Citation

(Scopus)
Recent trends in geotechnical earthquake engineering experimentation

A. Elgamal, A. B. Huang, M. Okamura

PHYSICAL MODELLING IN GEOTECHNICS, VOLS. 1 AND 2 1 ( 1 ) 23 - 44 2010 [Refereed]

DOI

Scopus

1

Citation

(Scopus)
Geotechnical damage caused by the 2010 Chile Maule, Chile earthquake

ISSMGE Bulletin 4 ( 2 ) 15 - 26 2010 [Refereed]
CONTRIBUTIONS TO "SOILS AND FOUNDATIONS": GROUND IMPROVEMENT

KITAZUME MASAKI, OKAMURA MITSU

SOILS AND FOUNDATIONS 50 ( 6 ) 965 - 975 2010

DOI CiNii

Scopus

8

Citation

(Scopus)
IDENTIFICATION OF MECHANICAL PROPERTIES IN SAND IMPROVED BY CALCIUM CARBONATE PRECIPITATED

HAYASHI Kazuyuki, TADANOBU Sayaka, YASUHARA Hideaki, OKAMURA Mitsu

Journal of Japan Society of Civil Engineers, Ser. C (Geosphere Engineering) 66 ( 1 ) 31 - 42 2010 [Refereed]

　View Summary

A series of drained triaxial tests was performed to clarify the effects of calcium carbonate precipitation on mechanical properties of sand. SEM-EDX was also utilized to examine the quality and quantity of the precipitated, revealing that calcium carbonate is the only mineral precipitated onto grain surfaces. Well-controlled triaxial test results show us that calcium carbonate precipitated within grain aggregate clearly augments Young's modulus and shear strength, and those magnitudes increase with the amount of the precipitated. This augmentation is attributed to increase of surface roughness (i.e., friction), and of positive dilatancy. The test results also demonstrate that intergrain adhesion mediated by the precipitation exerts influence significantly on the elastic deformation, but little on the strength.

DOI CiNii
Identification of liquefaction resistances in sand improved by calcium carbonate precipitated

HAYASHI Kazuyuki, OKAMURA Mitsu, YASUHARA Hideaki

Japanese Geotechnical Journal 5 ( 2 ) 391 - 400 2010

　View Summary

A suite of undrained cyclic triaxial tests was performed to clarify the effects of calcium carbonate precipitation on liquefaction resistance of sand. For the tests Toyoura sand was utilized with relative density of ca.50%. Two kinds of soil samples were prepared by mixing 1-3 wt.% precipitated calcium carbonate into Toyoura sand, and the difference of liquefaction resistances evolved under the two different initial conditions was examined. Triaxial tests results and the corresponding examinations elucidate that 1) liquefaction resistances of calcium carbonated precipitated sand increase with increase of the amount of the mineral precipitated (at maximum threefold), 2) the augmentation may be attributed mainly to improvement of deformation characteristics due to intergranular cohesion evolved by the mineral precipitation, and 3) the liquefaction resistance can be evaluated via a simple relation between normalized shear modulus and liquefaction resistance of bare sand.

DOI CiNii
Preliminary report of reconnaissance of the 2010 Maule, Chile, (offshore) earthquake

飛田哲男, 安田進, 小長井一男, 岡村未対, 菅野高弘

Journal of Japan Society for Natural Disaster Science 29 ( 1 ) 105 - 122 2010

CiNii J-GLOBAL
IDENTIFICATION OF MECHANICAL PROPERTIES IN SAND IMPROVED BY CALCIUM CARBONATE PRECIPITATED

HAYASHI Kazuyuki, TADANOBU Sayaka, YASUHARA Hideaki, OKAMURA Mitsu

Doboku Gakkai Ronbunshuu C 66 ( 1 ) 31 - 42 2010

　View Summary

  A series of drained triaxial tests was performed to clarify the effects of calcium carbonate precipitation on mechanical properties of sand. SEM-EDX was also utilized to examine the quality and quantity of the precipitated, revealing that calcium carbonate is the only mineral precipitated onto grain surfaces. Well-controlled triaxial test results show us that calcium carbonate precipitated within grain aggregate clearly augments Young's modulus and shear strength, and those magnitudes increase with the amount of the precipitated. This augmentation is attributed to increase of surface roughness (i.e., friction), and of positive dilatancy. The test results also demonstrate that intergrain adhesion mediated by the precipitation exerts influence significantly on the elastic deformation, but little on the strength.

DOI CiNii J-GLOBAL
Identification of liquefaction resistances in sand improved by calcium carbonate precipitated

林和幸, 岡村未対, 安原英明

地盤工学ジャーナル(Web) 5 ( 2 ) 391 - 400 2010 [Refereed]

DOI CiNii J-GLOBAL
空気注入による液状化対策工に対するモニタリング―三次元比抵抗トモグラフィによる空気注入範囲の可視化―

今里武彦, 武林昌哉, 西田克司, 藤井直, 岡村未対

地盤工学会誌 57 ( 5 ) 20-23,1(2) - 23 2009.05 [Refereed]

J-GLOBAL
Visualization of desaturated Area during Air Injection by 3-D Resistivity Tomography

IMASATO Takehiko, TAKEBAYASHI Masaya, NISHIDA Katsuji, FUJII Nao, OKAMURA Mitsu

地盤工学会誌 57 ( 5 ) 20 - 23 2009.05

　View Summary

In recent years, desaturation of loose sand deposits as a countermeasure against liquefaction attracts great attention of engineers. Methods of desaturation such as the air injection technique were developed and the relationship between degree of saturation and liquefaction resistance has already been established. In this study, an attempt was made to identify the area at a site by using the threedimensional resistivity tomography, where in-situ air injection test were conducted. It is confirmed that the area where resistivity of soil changed by air injection coincides with desaturated area. Distribution of degree of saturation in the area can be also estimated using the Archie's formulas and the resistivity change.

CiNii
LIQUEFACTION RESISTANCES OF UNSATURATED NON-PLASTIC SILT

Mitsu Okamura, Kohei Noguchi

SOILS AND FOUNDATIONS 49 ( 2 ) 221 - 229 2009.04 [Refereed]

DOI CiNii

Scopus

50

Citation

(Scopus)
Centrifuge model tests on soil desaturation as a liquefaction countermeasure

J. Takemura, R. Igarashi, J. Izawa, M. Okamura, M. Masuda

Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering: The Academia and Practice of Geotechnical Engineering 1 502 - 505 2009

DOI

Scopus

10

Citation

(Scopus)
Significance of settlement on seismic stability of Footing on Slope

Japanese Geotechnical SocietyInternational Conference on Performance-based design in earthquake geotechnical engineering ( 1 ) 603 - 606 2009
Centrifuge model tests on soil desaturation as a liquefaction countermeasure

J. Takemura, R. Igarashi, J. Izawa, M. Okamura, M. Masuda

Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering: The Academia and Practice of Geotechnical Engineering 1 ( 1 ) 502 - 505 2009 [Refereed]

DOI

Scopus

10

Citation

(Scopus)
IN-SITU TEST ON DESATURATION BY AIR INJECTION AND ITS MONITORING

OKAMURA Mitsu, TAKEBAYASHI Masaya, NISHIDA Katsuji, FUJII Nao, JINGUJI Motoharu, IMASATO Takehiko, YASUHARA Hideaki, NAKAGAWA Emiko

Journal of Japan Society of Civil Engineers, Ser. C (Geosphere Engineering) 65 ( 3 ) 756 - 766 2009 [Refereed]

　View Summary

Desaturation of ground by air injection attracts considerable attention in resent years as an innovative technique for liquefaction countermeasure. This technical report describes an in-situ air injection test which aims to confirm an effectiveness of the air injection to desaturate ground and validity of observation techniques to monitor the evaluation of unsaturated area. In the test, air was injected from an air injector set at a depth of 6m. Air flow rate increased linearly with increasing air injection pressure and desaturated area was formed within 4m from the injector. 3D resisitevity tomography and FDR probes were found to be effective to detect evolution of the desaturated area.

DOI CiNii
IN-SITU TEST ON DESATURATION BY AIR INJECTION AND ITS MONITORING

OKAMURA Mitsu, TAKEBAYASHI Masaya, NISHIDA Katsuji, FUJII Nao, JINGUJI Motoharu, IMASATO Takehiko, YASUHARA Hideaki, NAKAGAWA Emiko

Doboku Gakkai Ronbunshuu C 65 ( 3 ) 756 - 766 2009

　View Summary

  Desaturation of ground by air injection attracts considerable attention in resent years as an innovative technique for liquefaction countermeasure. This technical report describes an in-situ air injection test which aims to confirm an effectiveness of the air injection to desaturate ground and validity of observation techniques to monitor the evaluation of unsaturated area. In the test, air was injected from an air injector set at a depth of 6m. Air flow rate increased linearly with increasing air injection pressure and desaturated area was formed within 4m from the injector. 3D resisitevity tomography and FDR probes were found to be effective to detect evolution of the desaturated area.

DOI CiNii J-GLOBAL
EXPERIMENTS AND PREDICTIONS OF SOIL DESATURATION BY AIR-INJECTION TECHNIQUE AND THE IMPLICATIONS MEDIATED BY MULTIPHASE FLOW SIMULATION

Hideaki Yasuhara, Mitsu Okamura, Yoshinori Kochi

SOILS AND FOUNDATIONS 48 ( 6 ) 791 - 804 2008.12 [Refereed]

DOI CiNii

Scopus

29

Citation

(Scopus)
EXPERIMENTS AND PREDICTIONS OF SOIL DESATURATION BY AIR-INJECTION TECHNIQUE AND THE IMPLICATIONS MEDIATED BY MULTIPHASE FLOW SIMULATION

Hideaki Yasuhara, Mitsu Okamura, Yoshinori Kochi

SOILS AND FOUNDATIONS 48 ( 6 ) 791 - 804 2008.12 [Refereed]

DOI CiNii

Scopus

29

Citation

(Scopus)
明日の基礎工空気注入による液状化対策の実用化に向けて

岡村未対

基礎工 36 ( 1 ) 066 - 069 2008.01

J-GLOBAL
空気注入による液状化対策の実用化に向けて (特集明日の基礎工)

岡村未対

基礎工 36 ( 1 ) 66 - 69 2008.01

CiNii
A SIMPLE METHOD TO ASSESS SEISMIC STABILITY OF MASONRY WALLS RETAINING ROAD EMBANKMENT IN MOUNTANEOUS AREA

OKAMURA Mitsu, SHIGEMATSU Shinya

Doboku Gakkai Ronbunshuu C 64 ( 4 ) 770 - 775 2008

　View Summary

Bearing capacity failure of road retaining walls, of which foundation soil condition is not taken into account in the design practice, often results in the severe damage to road embankment during an earthquake. This paper proposes a simple method to assess seismic stability of existing masonry retaining walls. The seismic coefficient invoked in the method is derived based on case histories of damaged and non-damaged walls. It is shown that bearing capacity estimated based on blow count of the in-situ portable dynamic cone is an effective index to sort out seismically unstable walls from existing walls.

DOI CiNii J-GLOBAL
PREPERATION OF FULLY SATURATED MODEL GROUND IN CENTRIFUGE AND HIGH ACCURACY MEASUREMENT OF DEGREE OF SATURATION

OKAMURA Mitsu, KITAYAMA Hiroaki

Doboku Gakkai Ronbunshuu C 64 ( 3 ) 662 - 671 2008

　View Summary

Liquefaction resistance of soil dramatically increases with decreasing degree of saturation (S_r). This paper proposed a technique for preparing fully saturated model ground used for centrifuge tests. The technique was verified through a series of test on sands with different grain size. It was found that the air entrapped in the funicular saturation zone during the saturation process degrades degree of saturation. The high degree of saturation can be achieved by applying centrifugal acceralation during the process. The saturation process in centrifuge with an aid of vaccume pressure achieved S_r of 99.3% for sand with considerable amount of fines. A technique of high accuracy measurement of S_r is also developed.

DOI CiNii J-GLOBAL
State of Geo-hazard Mitigation in Shikoku Region against the Nankai Earthquake

YATABE Ryuichi, HASEGAWA Shuichi, OKAMURA Mitsu, BHANDARY Netra

Soil mechanics and foundation engineering 55 ( 5 ) 11 - 13 2007.05

　View Summary

This paper summarizes the efforts made towards mitigating geo-hazard in Shikoku Region due to the Nankai Earthquake within a few decades. At first, it introduces the characteristic features of alluvial deposits in Tokushima and Kochi plains. Being deposited in thick layers, these alluvial plains have greater potential for extensive damage during the Nankai Earthquake. Secondly, it introduces plans of Shikoku Regional Development Bureau and Shikoku Branch of West Nippon Expressway Company towards mitigating the earthquake hazard. Finally, the state of development of countermeasures towards mitigating potential hazard during the Nankai Earthquake under combined efforts of government agencies, private firms, and academic institutions is discussed.

CiNii
Geotechnical Perspectives of Landslide Mechanism in Serpentine Zone

YATABE Ryuichi, BHANDARY Netra, OKAMURA Mitsu

Nendo Kagaku 46 ( 1 ) 16 - 23 2007.02

　View Summary

This paper discusses landslide mechanism in serpentine dominated areas from geotechnical and mineralogical points of view. It first introduces typical features of landslide distribution in the serpentine zone, which is then supported by the discussion encompassing shear strength and mineralogical properties of the clay material involved in inducing serpentine zone landslides. The angles of shear resistance for the weathered serpentine clay samples were found to be comparatively high, which often does not lead to land sliding in gentle slopes, so the chances of smectite or expansive chlorite originated from other rock types being the cause of land sliding were found to be higher. For this reason, comparatively gentle serpentine slopes usually slide through the planes of boundary with other rock types. The dissolution tests on fine powder samples of serpentine revealed the influence of brucite, and the angles of shear resistance decrease notably with the release of ions. Finally, the shear strength and elemental analysis tests on the collected landslide clay samples revealed the influence of chemical weathering on decreased shear strength of clays.

DOI CiNii J-GLOBAL
Geotechnical Perspectives of Landslide Mechanism in Serpentine Zone

YATABE Ryuichi, BHANDARY Netra, OKAMURA Mitsu

Journal of the Clay Science Society of Japan (in Japanese) 46 ( 1 ) 16 - 23 2007

　View Summary

This paper discusses landslide mechanism in serpentine dominated areas from geotechnical and mineralogical points of view. It first introduces typical features of landslide distribution in the serpentine zone, which is then supported by the discussion encompassing shear strength and mineralogical properties of the clay material involved in inducing serpentine zone landslides. The angles of shear resistance for the weathered serpentine clay samples were found to be comparatively high, which often does not lead to land sliding in gentle slopes, so the chances of smectite or expansive chlorite originated from other rock types being the cause of land sliding were found to be higher. For this reason, comparatively gentle serpentine slopes usually slide through the planes of boundary with other rock types. The dissolution tests on fine powder samples of serpentine revealed the influence of brucite, and the angles of shear resistance decrease notably with the release of ions. Finally, the shear strength and elemental analysis tests on the collected landslide clay samples revealed the influence of chemical weathering on decreased shear strength of clays.

DOI CiNii
A simple method for evaluating seismic failure potential of retaining walls on slopes

Mitsu OKAMURA

土木学会Journal of Structural Engineering/Earthquake Engineering 24 ( 1 ) 31S - 37S 2007 [Refereed]

DOI CiNii

Scopus
A SIMPLE METHOD FOR EVALUATING SEISMIC FAILURE POTENTIAL OF RETAINING WALLS ON SLOPES

OKAMURA Mitsu

STRUCTURAL ENGINEERING / EARTHQUAKE ENGINEERING 24 ( 1 ) 31S - 37S 2007

　View Summary

In the design practice of retaining walls which support road embankments, stability under the action of strong earthquake ground motion is usually not examined. However, collapse of road embankments in mountainous area often results in cutting off road traffic and complete isolation of people in the neighborhood for a long time. The author surveyed a number of damaged and undamaged road embankments in the mountainous area where strong ground motions were recorded during the 2004 Niigataken-Chuetsu Earthquake. It was revealed that catas trophic failure of embankments constructed on sloping foundation soils were in many cases triggered by damage of retaining walls and most of such damaged retaining walls failed in the mechanism of the bearing capacity failure of the foundation soil. In this study a simple method to examine the seismic stability of existing retaining walls is developed, which evaluates a factor of safety for the bearing capacity failure of foundation on slope under combined loading in conjunction with soil strength parameters obtained by dynamic cone penetration tests using a portable testing device. A good correlation was found between the factor of safety of the surveyed walls derived from the method and the observed deformation of the walls, confirming the effectiveness of the method to identify seismically unstable walls out of existing walls.

DOI CiNii

Scopus
Present Scenario of Application of Soil Strength Tests in Natural Slope Stability Issues and the Challenges Ahead

Yatabe Ryuichi, Inagaki Hideki, Okamura Mitsu, Netra Bhandary

Soil mechanics and foundation engineering 54 ( 10 ) 12 - 14 2006.10

　View Summary

The use of shear-test-based strength parameters in stability analysis of natural slopes is in rare practice. The reasons can be divided into cases of surface slope failures and landslides. In case of surface slopes, decomposed inhomogeneous slope soil, difficulties involved in tests with accuracy under low normal stresses, and evaluation of the effect of plant roots on the strength are some of the factors, while in case of landslides, the influence of sample disturbance on the strength reduces reliability of the shear tests. With these problems on focus, this paper discusses present scenario and challenges in relation with the application of test-based strength parameters in slope stability issues.

CiNii
Effects of pore fluid compressibility on liquefaction resistance of partially saturated sand

Mitsu Okamura, Yasumasa Soga

SOILS AND FOUNDATIONS 46 ( 5 ) 695 - 700 2006.10 [Refereed]

DOI CiNii

Scopus

226

Citation

(Scopus)
Present Scenario of Application of Soil Strength Tests in Natural Slope Stability Issues and the Challenges Ahead

矢田部龍一, 稲垣秀輝, 岡村未対, BHANDARY Netra

土と基礎 54 ( 10 ) 12 - 14 2006.10 [Refereed]

J-GLOBAL
Inexpensive Liquefaction Countermeasure-Soil Desaturation by Air Injection

OKAMURA Mitsu

土と基礎 54 ( 7 ) 28 - 30 2006.07

CiNii J-GLOBAL
Degree of saturation and liquefaction resistances of sand improved with sand compaction pile

M Okamura, M Ishihara, K Tamura

JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING 132 ( 2 ) 258 - 264 2006.02 [Refereed]

DOI CiNii

Scopus

121

Citation

(Scopus)
Liquefied soil pressures on vertical walls with adjacent embankments

M Okamura, M Ishihara, K Tamura

SOIL DYNAMICS AND EARTHQUAKE ENGINEERING 26 ( 2-4 ) 265 - 274 2006.02 [Refereed]

DOI

Scopus

6

Citation

(Scopus)
Shaking table tests to investigate soil desaturation as a liquefaction countermeasure

Mitsu Okamura, Taiji Tetraoka

Geotechnical Special Publication 282 - 293 2006.01
Seismic performance of desaturated soil as a liquefaction countermeasure

M. Okamura, T. Teraoka

PHYSICAL MODELLING IN GEOTECHNICS - 6TH ICPMG '06, VOL 1 1-2 469 - + 2006
Effect on liquefaction resistance of volumetric strain of pore fluid

OKAMURA M.

Japanese Geotechnical SocietySoils and Foundations 46 ( 4 ) 703 - 708 2006 [Refereed]

CiNii
6. 地盤と構造物, 7. 地盤防災

岡村未対

土と基礎 = Soil mechanics and foundation engineering 53 ( 12 ) 74 - 75 2005.12

CiNii
地盤災害に関する国際シンポジウム(カザフスタン)開催報告

岡村未対

土と基礎 53 ( 8 ) 2005.08

CiNii
Comparative Study on Seismic Behavior of a Retaining Wall by Several FEM Programs(Theme: Application of Finite Element Analyses to Design of Geotechnical Constructions)

Koushige Norihiro, Okamura Mitsu, Wakai Akihiko, Shiomi Kazutoshi

Soil mechanics and foundation engineering 53 ( 8 ) 22 - 24 2005.08

　View Summary

This paper discusses results of finite element analysis (FEA) done by several researchers using different FE codes. Two researchers simulated centrifuge models of a gravity type retaining wall which was founded in dry sand and subjected to moderate to strong base shakings. Although the FE codes employed different constitutive models and the researcher chose considerably different quantity of strength parameter of the soil, results from both analysis including translation and rotation of the retaining wall and deformation of soil compared reasonably well with the test results.

CiNii
Comparative Study on Seismic Behavior of a Retaining Wall by Several FEM Programs

KOUSHIGE Norihiro, OKAMURA Mitsu, WAKAI Akihiko, SHIOMI Kazutoshi

土と基礎 53 ( 8 ) 22 - 24 2005.08

　View Summary

This paper discusses results of finite element analysis (FEA) done by several researchers using different FE codes. Two researchers simulated centrifuge models of a gravity type retaining wall which was founded in dry sand and subjected to moderate to strong base shakings. Although the FE codes employed different constitutive models and the researcher chose considerably different quantity of strength parameter of the soil, results from both analysis including translation and rotation of the retaining wall and deformation of soil compared reasonably well with the test results.

CiNii J-GLOBAL
平成16年豪雨による土砂災害平成16年の四国の台風災害の概要と特性

矢田部龍一, 長谷川修一, バンダリーネトラ, 岡村未対

自然災害科学 24 ( 2 ) 139 - 149 2005.08 [Refereed]

J-GLOBAL
Shaking table tests to investigate soil desaturation as a liquefaction countermeasure

Geotechnical Special Publication, ASCE 145 282 - 293 2005
山岳盛土擁壁の簡易な耐震性点検法に関する研究

土木学会地震工学論文集 28 Paper No. 003 2005
平成16年の四国の台風災害の概要と特性 (特集記事平成16年豪雨による土砂災害)

矢田部龍一, 長谷川修一, バンダリーネトラ, 岡村未対

自然災害科学 24 ( 2 ) 139 - 149 2005

CiNii
異なる地下水位下での液状化時杭基礎挙動に関する遠心模型実験

林和幸, 杉田秀樹, 高橋章浩, 谷本俊輔, 田村敬一, 岡村未対, 三上卓

液状化地盤中の杭の挙動の設計法に関するシンポジウム発表論文集 211 - 216 2004.12 [Refereed]
遠心模型実験-実験技術と実務への適用 : 3. 予測手段, 予測対象としての遠心模型実験

岡村未対, 萩原敏行, 松田隆

土と基礎 = Soil mechanics and foundation engineering 52 ( 11 ) 51 - 58 2004.11

CiNii
遠心模型実験―実験技術と実務への適用 3.予測手段,予測対象としての遠心模型実験

岡村未対, 萩原敏行, 松田隆

土と基礎 52 ( 11 ) 51-58,1(4) 2004.11 [Refereed]

J-GLOBAL
地震時変形を考慮した河川堤防の液状化対策工設計法 (特集:土木構造物の耐震補強技術)

石原雅規, 岡村未対, 田村敬一

土木技術資料 46 ( 10 ) 48 - 53 2004.10

CiNii
遠心模型実験-実験技術と実務への適用- : 2. 遠心模型の相似則, 実験技術-利点と限界

岡村未対, 竹村次朗, 上野勝利

土と基礎 = Soil mechanics and foundation engineering 52 ( 10 ) 37 - 44 2004.10

CiNii
遠心模型実験―実験技術と実務への適用―2.遠心模型の相似則,実験技術―利点と限界

岡村未対, 竹村次朗, 上野勝利

土と基礎 52 ( 10 ) 37-44,1(5)-1(6) 2004.10 [Refereed]

J-GLOBAL
土木構造物の耐震補強技術地震時変形を考慮した河川堤防の液状化対策工設計法

石原雅規, 岡村未対, 田村敬一, 杉田秀樹

土木技術資料 46 ( 10 ) 48 - 53 2004.10 [Refereed]

J-GLOBAL
PREDICTION METHOD FOR LIQUEFACTION-INDUCED SETTLEMENT OF EMBANKMENT WITH REMEDIAL MEASURE BY DEEP MIXING METHOD

OKAMURA MITSU, TAMURA KEIICHI

Journal of the Japanese Geotechnical Society 44 ( 4 ) 53 - 65 2004.08

　View Summary

In order to mitigate liquefaction-induced embankment settlement, remedial measures are often implemented for existing embankments. This paper describes a practical prediction method for embankment settlement due to foundation liquefaction, which are remedied with the deep mixing method. Based on a number of centrifuge shaking tests of embankment, an empirical relation between crest settlement and displacement of the remedied zone is established. Then, a calculation method for displacement of the remedied zone is developed. In the method, a macroscopic failure envelope and a plastic displacement potential in the general load space are considered to evaluate the subgrade reaction forces on the base of the remedied zone. The method is capable of calculating not only horizontal, vertical or rotational displacement alone, but their combined effect. The method is validated through comparisons of calculated results with centrifuge test observations. The calculated displacement components compare quite well with those measured. This method can be a useful tool for design of countermeasures based on a specified limit settlement.

DOI CiNii

Scopus

7

Citation

(Scopus)
Prediction method for liquefaction-induced settlement of embankment with remedial measure by deep mixing method

M Okamura, K Tamura

SOILS AND FOUNDATIONS 44 ( 4 ) 53 - 65 2004.08 [Refereed]
STUDY ON EARTHQUAKE-PROOF PROPERTY OF ROAD EMBANKMENT ON SOFT CLAY GROUND INCLUDING LOOSE SANDY LAYER

INOUE Yasutake, OCHIAI Hidetoshi, MATSUO Osamu, OKAMURA Mitsu, MORI Masahumi

( 757 ) 139 - 154 2004.03 [Refereed]

DOI CiNii
Ground Improvement (2)

岡村未対

Soil mechanics and foundation engineering 52 ( 3 ) 23 - 23 2004.03

CiNii
上下部構造の連成を考慮した耐震性能の実験的検証法に関する研究

田村敬一, 岡村未対, 谷本俊輔

土木研究所成果報告書 2003 89 - 94 2004.03

J-GLOBAL
On degree of saturation of ground improved with SCP

Okamura Mitsu, Ishihara Masanori, Tamura Keiichi

Proceedings of the Japan National Conference on Geotechnical Engineering 39 ( 0 ) 1001 - 1002 2004

　View Summary

サンドコンパクションパイル(SCP)工法で改良した地盤の飽和度を調査した報告によると、SCP施工直後の改良地盤の飽和度はおよそ70%~90%とかなりの程度低下している。地盤の飽和度が低下すると液状化抵抗は急激に大きくなるが、実務設計において低下した飽和度を考慮した液状化強度を用いるためには、飽和度の経時変化を調べることが必要である。SCP改良地盤の飽和度に関しては、改良直後の二,三の調査結果がこれまでに報告されているだけであり、長期的な飽和度の変化についてはほとんど知られていない。そこで、数年前にSCPで改良された地盤において原位置試験を行うとともに凍結サンプリング試料を採取し、試料の飽和度を測定したのでその結果を報告する。

DOI CiNii
PREDICTION METHOD FOR LIQUEFACTION-INDUCED SETTLEMENT OF EMBANKMENT WITH REMEDIAL MEASURE BY DEEP MIXING METHOD

OKAMURA MITSU, TAMURA KEIICHI

SOILS AND FOUNDATIONS 44 ( 4 ) 53 - 65 2004

　View Summary

In order to mitigate liquefaction-induced embankment settlement, remedial measures are often implemented for existing embankments. This paper describes a practical prediction method for embankment settlement due to foundation liquefaction, which are remedied with the deep mixing method. Based on a number of centrifuge shaking tests of embankment, an empirical relation between crest settlement and displacement of the remedied zone is established. Then, a calculation method for displacement of the remedied zone is developed. In the method, a macroscopic failure envelope and a plastic displacement potential in the general load space are considered to evaluate the subgrade reaction forces on the base of the remedied zone. The method is capable of calculating not only horizontal, vertical or rotational displacement alone, but their combined effect. The method is validated through comparisons of calculated results with centrifuge test observations. The calculated displacement components compare quite well with those measured. This method can be a useful tool for design of countermeasures based on a specified limit settlement.

DOI CiNii

Scopus

7

Citation

(Scopus)
DEVELOPMENT OF HYBRID VIBRATION EXPERIMENT TECHNIQUE FOR ASSESSING SEISMIC PERFORMANCE OF PILE FOUNDATIONS WITH SUPERSTRUCTURE

田村敬一, 岡村未対, 谷本俊輔

土木研究所重点プロジェクト研究報告書平成15年度 366 - 372 2004

J-GLOBAL
STUDY ON EARTHQUAKE-PROOF PROPERTY OF ROAD EMBANKMENT ON SOFT CLAY GROUND INCLUDING LOOSE SANDY LAYER

INOUE Yasutake, OCHIAI Hidetoshi, MATSUO Osamu, OKAMURA Mitsu, MORI Masahumi

Doboku Gakkai Ronbunshu 2004 ( 757 ) 139 - 154 2004

　View Summary

In the earthquake-proof design of the road embankment by performance-based design, it is necessary to recognize quantitatively the amount of settlement due to the earthquake, since the earthquake-proof ability is estimated on the settlement at the top of embankment as an index. The seismic motion and the rank of the road are also considered in the design. In this research, in order to investigate the seismic behavior of road embankment on the soft ground which is improved by Deep Mixing Method and Sand Compaction Pile method, dynamic centrifuge model test and dynamic FEM analysis were performed.

DOI CiNii J-GLOBAL
河川堤防耐震対策工の性能設計

岡村未対, 石原雅規, 田村敬一

日本地震工学会大会梗概集 2nd 108 - 109 2003.11

J-GLOBAL
LIQUEFACTION RESISTANCE OF SAND DEPOSIT IMPROVED WITH SAND COMPACTION PILES

OKAMURA MITSU, ISHIHARA MASANORI, OSHITA TAKESHI

Journal of the Japanese Geotechnical Society 43 ( 5 ) 175 - 187 2003.10

　View Summary

This paper reports results of in-situ tests and undrained cyclic shear tests on high-quality undisturbed samples obtained by the in-situ freezing method at three sites where foundation soils had been improved with sand compaction piles. Triaxial specimens obtained from the frozen samples were fully saturated in the triaxial cell and then subjected to cyclic loadings. In the current design practice of ground improvement with the sand compaction piles, the SPT N-value at a mid point of a rectangular area surrounded by four adjacent sand piles, at which the N-value, and thus the liquefaction resistance is considered to be the smallest, is set as a target for the degree of compaction. It was found, however, that distributions of N-values and N_d-values in a horizontal plane at a certain depth appeared to be rather random. This suggests that the V-Value at the center of a rectangular area does not always provide a conservative evaluation. The relationship between liquefaction resistances and the N-value, which was developed based mainly on field evidences of earthquake-induced liquefaction of natural soil deposits and reclaimed lands, compared quite well with that obtained from tests on fully saturated high quality specimens and mean values of N_d at several locations in the improved sands. Degree of saturation of the frozen sample was revealed to be considerably low, in the range between about 70 and 90%. This fact indicates that the liquefaction resistances of improved sands are significantly higher than those obtained from the relationship which is available only for fully saturated soils.

DOI CiNii

Scopus

46

Citation

(Scopus)
Liquefaction resistance of sand deposit improved with sand compaction piles

M Okamura, M Ishihara, T Oshita

SOILS AND FOUNDATIONS 43 ( 5 ) 175 - 187 2003.10 [Refereed]
許容沈下量に基づいた河川堤防の液状化対策工法設計マニュアル

田村敬一, 岡村未対, 石原雅規, 松尾修

土木研究所資料 ( 3889 ) 100P 2003.09

J-GLOBAL
Seismic displacement of spread foundations on soft rock beds

岡村未対, 松尾修, 田村敬一

構造工学論文集 A 49A ( 3 ) 1229 - 1236 2003.03 [Refereed]

J-GLOBAL
Prediction method of liquefaction-induced settlement of remedied embankment with deep mixing method

M Okamura, M Ishihara, K Tamura

SOFT GROUND ENGINEERING IN COASTAL AREAS 305 - 310 2003 [Refereed]
LIQUEFACTION RESISTANCE OF SAND DEPOSIT IMPROVED WITH SAND COMPACTION PILES

OKAMURA MITSU, ISHIHARA MASANORI, OSHITA TAKESHI

SOILS AND FOUNDATIONS 43 ( 5 ) 175 - 187 2003

　View Summary

This paper reports results of in-situ tests and undrained cyclic shear tests on high-quality undisturbed samples obtained by the in-situ freezing method at three sites where foundation soils had been improved with sand compaction piles. Triaxial specimens obtained from the frozen samples were fully saturated in the triaxial cell and then subjected to cyclic loadings. In the current design practice of ground improvement with the sand compaction piles, the SPT N-value at a mid point of a rectangular area surrounded by four adjacent sand piles, at which the N-value, and thus the liquefaction resistance is considered to be the smallest, is set as a target for the degree of compaction. It was found, however, that distributions of N-values and N_d-values in a horizontal plane at a certain depth appeared to be rather random. This suggests that the V-Value at the center of a rectangular area does not always provide a conservative evaluation. The relationship between liquefaction resistances and the N-value, which was developed based mainly on field evidences of earthquake-induced liquefaction of natural soil deposits and reclaimed lands, compared quite well with that obtained from tests on fully saturated high quality specimens and mean values of N_d at several locations in the improved sands. Degree of saturation of the frozen sample was revealed to be considerably low, in the range between about 70 and 90%. This fact indicates that the liquefaction resistances of improved sands are significantly higher than those obtained from the relationship which is available only for fully saturated soils.

DOI CiNii

Scopus

46

Citation

(Scopus)
10. Researches of durability improvement and performance evaluation method of structures. 10.5. Researches of experimental verification method of earthquake resistant performance taking the coupling of superstructures and substructures into consideration.

田村敬一, 岡村未対, 谷本俊輔

土木研究所重点プロジェクト研究報告書平成14年度 331 - 335 2003

J-GLOBAL
10. Researches of durability improvement and performance evaluation method of structures. 10.4. Test and investigation of seismic resistant design method for bridge foundation based on the deformation of liquefied ground.

田村敬一, 岡村未対, 星隈順一, 谷本俊輔

土木研究所重点プロジェクト研究報告書平成14年度 326 - 330 2003

J-GLOBAL
14. Researches of construction cost reduction technology of super long highway structures. 14.2. Test and investigation of rationalizing the seismic resistant design method of long span bridges on the assumption of large-scale earthquake. ( 1 ).

田村敬一, 岡村未対, 谷本俊輔

土木研究所重点プロジェクト研究報告書平成14年度 518 - 520 2003

J-GLOBAL
土工構造物・地中構造物の動的遠心模型実験

佐々木哲也, 田村敬一, 岡村未対

土木技術資料 45 ( 1 ) 38 - 41 2003.01

CiNii J-GLOBAL
液状化地盤上の橋梁構造物の振動台実験

小野和行, 鈴木貴喜, 田村敬一, 岡村未対, 近藤益央, 谷本俊輔

土木技術資料 45 ( 1 ) 26 - 29 2003.01

CiNii J-GLOBAL
上下部構造の連成を考慮した橋梁のハイブリッド振動実験

谷本俊輔, 田村敬一, 岡村未対, 小林寛

土木技術資料 45 ( 1 ) 22 - 25 2003.01

CiNii J-GLOBAL
On liquefaction resistance and degree of saturation of sand improved with SCP

Okamura Mitsu, Ishihara Masanori, Tamura Keiichi

Proceedings of the Japan National Conference on Geotechnical Engineering 38 ( 0 ) 2025 - 2026 2003

　View Summary

This paper reports results of in-situ tests and undrained cyclic shear tests on high-quality undisturbed samples obtained by in-situ freezing method at three sites where foundation soils had been improved with the sand compaction pile. The relationship between liquefaction resistances and N-value, which was developed based mainly on the field evidences of earthquake-induced liquefaction of natural soil deposits and reclaimed lands, compared quite well with that obtained from tests on fully saturated high quality specimens and mean value of Nd at several locations in the improved sands. Degree of saturation of the frozen sample was revealed to be considerably low, in the range between about 70 and 90 %.

DOI CiNii J-GLOBAL
EFFECTS OF FOOTING SIZE AND ASPECT RATIO ON THE BEARING CAPACITY OF SAND SUBJECTED TO ECCENTRIC LOADING

OKAMURA Mitsu, MIHARA Atsunori, TAKEMURA Jiro, KUWANO Jiro

Journal of the Japanese Geotechnical Society 42 ( 4 ) 43 - 56 2002.08

　View Summary

The current practice of estimating bearing capacity usually employs the conventional bearing capacity formula originally developed for strip footings under vertical central loading. In order to account for the effect of footing shape and eccentricity and inclination of loads, correction factors are introduced in the formula, which are derived based on a number of small-scale model test observations. This paper describes research on the bearing capacity of rectangular footings on sand subjected to vertical eccentric loading. Two aspects, namely the effects of footing size and of footing shape on the bearing capacity and deformation characteristics, are focused on. A series of loading tests was conducted in a centrifuge on rectangular footings with aspect ratios from 1 to 5, at two different centrifugal accelerations. In addition, finite element analyses were performed in which factors influencing the angle of shear resistance including stress level dependency, anisotropy and coefficient of intermediate principal stress, were taken into account. It was found that the shape factor of footing apparently increased with increasing footing width. This indicates that the shape factor used in the current practice underestimates bearing capacity of footings. This was also the case for failure locus in the M/B-V (moment-vertical) load plane. Normalized failure locus for wider footings with a smaller aspect ratio is considerably larger than that reported in the literature. The stress level dependency of the angle of shear resistance appeared to be responsible for the scale effects of footings on the failure locus.

DOI CiNii

Scopus

34

Citation

(Scopus)
Effects of footing size and aspect ratio on the bearing capacity of sand subjected to eccentric loading

M Okamura, A Mihara, J Takemura, J Kuwano

SOILS AND FOUNDATIONS 42 ( 4 ) 43 - 56 2002.08 [Refereed]
A DISPLACEMENT PREDICTION METHOD FOR RETAINING WALLS UNDER SEISMIC LOADING

OKAMURA Mitsu, MATSUO Osamu

Journal of the Japanese Geotechnical Society 42 ( 1 ) 131 - 138 2002.02

DOI CiNii

Scopus

17

Citation

(Scopus)
A displacement prediction method for retaining walls under seismic loading

M Okamura, O Matsuo

SOILS AND FOUNDATIONS 42 ( 1 ) 131 - 138 2002.02 [Refereed]
A Displacement Prediction Method for Retaining Walls under Seismic Loading.

OKAMURA MITSU, MATSUO OSAMU

SOILS AND FOUNDATIONS 42 ( 1 ) 131 - 138 2002

　View Summary

This paper describes a new calculation method for seismic displacement of retaining walls. A macroscopic failure surface and a plastic displacement potential in the general load space are considered in the method to evaluate the subgrade reaction force from foundation ground. The method is capable of calculating not only horizontal, vertical or rotational displacement alone, but also their combined effect. The method is validated through comparison with centrifuge test results of a gravity retaining wall with dense backfill sand subjected to strong base shaking. The calculated displacement components, that is vertical, horizontal and rotational displacement at the end of shaking, compared well with those measured. It also appeared that previously proposed conventional displacement calculation methods based on Newmark's sliding block analogy might underestimate the displacement. The assumption of the constant frictional coefficient may be responsible for this. The proposed method is limited to retaining walls resting on soils where dramatic degradation of soil strength due to the generation of excess pore pressure does not occur.

DOI CiNii

Scopus

17

Citation

(Scopus)
Effects of Footing Size and Aspect Ratio on the Bearing Capacity of Sand Subjected to Eccentric Loading.

OKAMURA MITSU, MIHARA ATSUNORI, TAKEMURA JIRO, KUWANO JIRO

SOILS AND FOUNDATIONS 42 ( 4 ) 43 - 56 2002

DOI CiNii

Scopus

34

Citation

(Scopus)
A DISPLACEMENT PREDICTION METHOD FOR RETAINING WALLS UNDER SEISMIC LOADING :

OKAMURA MITSU, MATSUO OSAMU

42 ( 1 ) 131 - 138 2002

　View Summary

This paper describes a new calculation method for seismic displacement of retaining walls. A macroscopic failure surface and a plastic displacement potential in the general load space are considered in the method to evaluate the subgrade reaction force from foundation ground. The method is capable of calculating not only horizontal, vertical or rotational displacement alone, but also their combined effect. The method is validated through comparison with centrifuge test results of a gravity retaining wall with dense backfill sand subjected to strong base shaking. The calculated displacement components, that is vertical, horizontal and rotational displacement at the end of shaking, compared well with those measured. It also appeared that previously proposed conventional displacement calculation methods based on Newmark's sliding block analogy might underestimate the displacement. The assumption of the constant frictional coefficient may be responsible for this. The proposed method is limited to retaining walls resting on soils where dramatic degradation of soil strength due to the generation of excess pore pressure does not occur.

DOI CiNii

Scopus

17

Citation

(Scopus)
EFFECTS OF SAND PERMEABILITY AND WEAK AFTERSHOCKS ON EARTHQUAKE-INDUCED LATERAL SPREADING

OKAMURA Mitsu, ABDOUN Tarek H., DOBRY Ricardo, SHARP Michael K., TABOADA Victor M.

SOILS AND FOUNDATIONS 41 ( 6 ) 63 - 77 2001.12

　View Summary

Centrifuge research conducted at Rensselaer Polytechnic Institute (RPI) is summarized focusing on the effect of sand permeability and of weak aftershocks on earthquake-induced lateral spreading. One-dimensional shaking tests were conducted in a laminar box at a centrifugal acceleration of 50 g, simulating a 10 m thick homogeneous layer of clean Nevada sand of relative density 40-45% inclined a few degrees to the horizontal. Seven centrifuge experiments were done using either water or a viscous pore fluid fifty times more viscous than water, thus varying the soil permeability by a factor of fifty and simulating either a coarse prototype sand or a fine sand in the field. These seven tests were subjected to the same shape of base input excitation but with peak input accelerations ranging from 0.18 g to 0.46 g between tests. An additional special centrifuge test of a similar model with viscous pore fluid was subjected to a strong base "main shock", followed after a few seconds by two "weak aftershocks". Excess pore pressures, accelerations, settlements and lateral ground deformations were measured. The results are discussed in detail and several correlations are presented between testing and measured parameters such as thickness of liquefied soil, ground surface settlement, lateral ground displacement and input peak acceleration. The results of the special test, together with other evidence, provide strong support to the hypothesis that reported continued ground deformations from lateral spreads in the field are often caused by continued weak vibration or aftershocks occurring after the main shock.

DOI CiNii

Scopus

41

Citation

(Scopus)
鋼矢板二重仮締切の地震時安定性に関する実験的検討 (液状化特集)

岡村未対, 松尾修

土木技術資料 43 ( 2 ) 64 - 69 2001.02

CiNii
鋼矢板二重仮締切の地震時安定性に関する実験的検討

岡村未対, 松尾修

土木技術資料 43 ( 2 ) 64 - 69 2001.02

J-GLOBAL
Effects of sand permeability and weak aftershocks on earthquake-induced lateral spreading

Mitsu Okamura, Tarek H. Abdoun, Ricardo Dobry, Michael K. Sharp, Victor M. Taboada

Soils and Foundations 41 ( 6 ) 63 - 77 2001 [Refereed]

DOI

Scopus

41

Citation

(Scopus)
固化改良により液状化対策を行った盛土の地震時沈下量評価法

岡村未対, 松尾修

地震工学研究発表会講演論文集 26 ( 26 ) 829 - 832 2001

　View Summary

本研究では, 法尻直下液状化層を固化改良した盛土の地震時変形特性を一連の遠心模型実験によって調べた。また改良体の変位量について, 支持地盤の組合せ荷重下での支持力特性を考慮した地盤反力の極限値を設定し, 変位増分方向に関する制約を与えた簡易動的解析法を考案し, 遠心模型実験を対象とした計算を行うことによってその適用性を確認した。盛土直下地盤の体積圧縮による盛土沈下量を別途評価し, この解析から求まる側方流動面積と盛土法尻の水平変位量から得られる天端沈下量を足し合わせることにより, 法先地盤を固化改良した盛土の地震時沈下量がある程度の精度で評価できる。

DOI CiNii
擁壁に作用する地震時主働土圧に関する考察および比較計算

松尾修, 斉藤由紀子, 岡村未対

地震工学研究発表会講演論文集 26 ( 26 ) 729 - 732 2001

　View Summary

擁壁・背面土の2体剛体モデルにより、擁壁に作用する地震時主働土圧を簡易的に評価した。また、多自由度地震時変位計算法を用い、遠心模型実験の実測土圧および本論文で提案している簡易式から求めた土圧を外力として擁壁の変位を試算した。その結果、変位計算法は実測土圧を用いることにより実験で得られた変位をある程度再現できること、簡易土圧式を外力とした場合も定性的には実験結果を表現できることがわかった。

DOI CiNii
複合構造物・他(動的問題1,2,補強土1,2)(6.地盤と構造物)

岡村未対

土と基礎 49 ( 12 ) 49 - 50 2001

CiNii
偏心荷重を受ける砂地盤の支持力・変形特性に及ぼす基礎の形状と寸法の影響

岡村未対, 三原淳慎, 竹村次朗, 桑野二郎

地盤工学シンポジウム論文集 45th 61 - 64 2000.10 [Refereed]

J-GLOBAL
軟岩に支持される直接基礎の地震時残留沈下量の評価手法 (長大橋特集)

松尾修, 岡村未対

土木技術資料 42 ( 8 ) 56 - 61 2000.08

CiNii
軟岩に支持される直接基礎の自信時残留沈下量の評価手法

松尾修, 岡村未対

土木技術資料 42 ( 8 ) 56 - 61 2000.08

J-GLOBAL
軟岩上直接基礎の地震時沈下量に関する簡易評価手法の適用性

岡村未対, 松尾修, 白井太郎

地盤工学研究発表会発表講演集 35th 1889 - 1890 2000.05

J-GLOBAL
軟岩上直接基礎の地震時沈下量に関する遠心模型実験

岡村未対, 松尾修, 田本修一

地盤工学研究発表会発表講演集 35th 1887 - 1888 2000.05

J-GLOBAL
地盤の液状化が想定される地盤上の盛土の地震時安定性

岡村未対

土と基礎 = Soil mechanics and foundation engineering 48 ( 4 ) 36 - 37 2000.04

CiNii
International Workshop on Geotechnology for Natural Hazards

Okamura Mitsu

Soil mechanics and foundation engineering 48 ( 3 ) 26 - 26 2000.03

CiNii
有効応力に基づいた弾塑性FEMによる河川堤防の地震時変形量に関する解析 (建設省土木研究所S)

松尾修, 岡村未対, 島津多賀夫

土木研究所資料 ( 3700 ) 344P 2000.03

J-GLOBAL
法先固化改良による盛土の耐震対策効果に関する動的遠心模型実験報告書 (建設省土木研究所S)

松尾修, 岡村未対, 田本修一

土木研究所資料 3688 ( 3688 ) 286P - 310 2000.03

CiNii J-GLOBAL
Numerical analyses of the damaged dikes in the 1995 Hyogo-ken Nanbu earthquake

Matsuo, O, Okamura, M, Uzuoka, R, Mihara, M

Proc. of 12th World Conference on Earthquake Engineering 2000.01

CiNii
Bearing Capacity of Sand layer Overlying Deep Clay Deposit.

岡村未対, 竹村次郎, 木村孟

地盤工学シンポジウム論文集 44th 207 - 216 1999.11 [Refereed]

J-GLOBAL
地盤工学会研究奨励賞を受賞して

岡村未対

土と基礎 = Soil mechanics and foundation engineering 47 ( 8 ) 70 - 70 1999.08

CiNii
遠心模型実験に関する国際会議(IS-TOKYO '98)開催報告

岡村末対, 堀越研一, 片桐雅明, 玉手聡

土と基礎 = Soil mechanics and foundation engineering 47 ( 3 ) 64 - 66 1999.03

CiNii
Effect of sheet piling as a measure against liquefaction-induced embankment failure

M Okamura, O Matsuo, Y Koga

EARTHQUAKE GEOTECHNICAL ENGINEERING, VOLS 1-3 731 - 736 1999
河川堤防の地震時安定性評価に対する円弧すべり計算法の適用性について

田本修一, 岡村未対, 松尾修

土木学会地震工学研究発表会講演論文集 25th ( 25 ) 385 - 388 1999

DOI CiNii J-GLOBAL
地盤液状化問題における弾塑性有限要素解析法の適用 (数値シミュレ-ション特集)

松尾修, 岡村未対, 島津多賀夫

土木技術資料 40 ( 8 ) 50 - 55 1998.08

CiNii
Application of Finite Element Method to Liquefaction Problem.

松尾修, 岡村未対, 島津多賀夫, 西邦夫

土木技術資料 40 ( 8 ) 50 - 55 1998.08

J-GLOBAL
下部に粘土層を有する砂層の極限平衡法による支持力計算

岡村未対, 竹村次朗, 木村孟

土と基礎 = Soil mechanics and foundation engineering 46 ( 4 ) 74 - 74 1998.04

CiNii
BEARING CAPACITY PREDICTIONS OF SAND OVERLYING CLAY BASED ON LIMIT EQUILIBRIUM METHODS

OKAMURA Mitsu, TAKEMURA Jiro, KIMURA Tsutomu

Journal of the Japanese Geotechnical Society 38 ( 1 ) 181 - 194 1998.03

　View Summary

A dense sand layer is usually assumed to be a bearing stratum in foundation design. It is, however, difficult for engineers to judge if a sand layer with limited thickness can be used as a bearing stratum when it is underlain by a thick soft clay deposit. Many important parameters must be considered in this problem, for example, the thickness of the sand, strength of clay and width, shape and embedment of footing. Several methods have been proposed to calculate the bearing capacities of the sand overlying clay, in which limit equilibrium of forces acting on an imaginary sand block between the base of the footing and the sand/clay interface was considered. The bearing capacities calculated based on existing methods are not the same for different assumptions adopted in each method. The shape of the sand block and the forces acting on the surface of the block are the determining factors in the bearing capacity calculation. In this paper, these factors as well as calculated bearing capacities are compared with the results of well-conditioned centrifuge tests (Okamura et al., 1997) to verify the validity of the methods. It has been confirmed that reasonable assumptions in which the variation of the shape of the sand block and the forces related to the parameters are taken into consideration are important to obtain a reasonable prediction. An alternative method is proposed and the bearing capacity charts are presented for easy reference.

DOI CiNii

Scopus

87

Citation

(Scopus)
Shaking table test report on sheet pile closing method as a bank liquefaction countermeasure. (Public Works Res. Inst., Ministry of Construction S).

松尾修, 岡村未対, 堤達也, 斉藤由紀子

土木研究所資料 ( 3539 ) 398P 1998.03

J-GLOBAL
Bearing capacity predictions of sand overlying clay based on limit equilibrium methods

Mitsu Okamura, Jiro Takemura, Tsutomu Kimura

Soils and Foundations 38 ( 1 ) 181 - 194 1998 [Refereed]

DOI

Scopus

87

Citation

(Scopus)
Load-settlement behavior of shallow footings on compressible sand deposits

M Okamura, F Sahara, J Takemura, O Kusakabe

CENTRIFUGE 98, VOL 1 435 - 440 1998 [Refereed]
Bearing Capacity Predictions of Sand Overlying Clay Based on Limit Equilibrium Methods.

OKAMURA MITSU, TAKEMURA JIRO, KIMURA TSUTOMU

SOILS AND FOUNDATIONS 38 ( 1 ) 181 - 194 1998

　View Summary

A dense sand layer is usually assumed to be a bearing stratum in foundation design. It is, however, difficult for engineers to judge if a sand layer with limited thickness can be used as a bearing stratum when it is underlain by a thick soft clay deposit. Many important parameters must be considered in this problem, for example, the thickness of the sand, strength of clay and width, shape and embedment of footing. Several methods have been proposed to calculate the bearing capacities of the sand overlying clay, in which limit equilibrium of forces acting on an imaginary sand block between the base of the footing and the sand/clay interface was considered. The bearing capacities calculated based on existing methods are not the same for different assumptions adopted in each method. The shape of the sand block and the forces acting on the surface of the block are the determining factors in the bearing capacity calculation. In this paper, these factors as well as calculated bearing capacities are compared with the results of well-conditioned centrifuge tests (Okamura et al., 1997) to verify the validity of the methods. It has been confirmed that reasonable assumptions in which the variation of the shape of the sand block and the forces related to the parameters are taken into consideration are important to obtain a reasonable prediction. An alternative method is proposed and the bearing capacity charts are presented for easy reference.

DOI CiNii

Scopus

87

Citation

(Scopus)
CENTRIFUGE MODEL TESTS ON BEARING CAPACITY AND DEFORMATION OF SAND LAYER OVERLYING CLAY

OKAMURA Mitsu, TAKEMURA Jiro, KIMURA Tsutomu

Journal of the Japanese Geotechnical Society 37 ( 1 ) 73 - 88 1997.03

　View Summary

A series of centrifuge model loading tests on dense sand overlying soft clay was carried out to investigate its bearing capacity and associated deformation including the failure mechanism. The effects of the thickness of sand, the strength of underlying clay and the width, shape and embedment of footings on the bearing behavior of the sand were studied. It was found that the bearing capacity increases with increasing sand thickness-footing width ratio until it reaches that of uniform sand, which can be considered as the upper limit of the bearing capacity of the layered soil. The bearing capacity also increases linearly with both the strength of the clay and the overburden pressure at the footing base. For cases with bearing capacity smaller than that for uniform sand, punching shear takes place, where a truncated cone shaped sand block between the footing base and the clay surface penetrates into the clay. The side angle of the sand block to the vertical increases with increasing sand thickness-footing width ratio and overburden pressure, and decreasing clay strength. It was confirmed that this variation of the angle should be taken into account in the bearing capacity calculation.

DOI CiNii
矢板工による盛土周辺地盤の沈下抑制効果に関する遠心模型実験

竹村次朗, 石井裕泰, 岡村未対

研究報告 ( 55 ) 61 - 78 1997.03

CiNii
Centrifuge Model Tests on Bearing Capacity and Deformation of Sand Layer Overlying Clay.

OKAMURA MITSU, TAKEMURA JIRO, KIMURA TSUTOMU

SOILS AND FOUNDATIONS 37 ( 1 ) 73 - 88 1997

　View Summary

A series of centrifuge model loading tests on dense sand overlying soft clay was carried out to investigate its bearing capacity and associated deformation including the failure mechanism. The effects of the thickness of sand, the strength of underlying clay and the width, shape and embedment of footings on the bearing behavior of the sand were studied. It was found that the bearing capacity increases with increasing sand thickness-footing width ratio until it reaches that of uniform sand, which can be considered as the upper limit of the bearing capacity of the layered soil. The bearing capacity also increases linearly with both the strength of the clay and the overburden pressure at the footing base. For cases with bearing capacity smaller than that for uniform sand, punching shear takes place, where a truncated cone shaped sand block between the footing base and the clay surface penetrates into the clay. The side angle of the sand block to the vertical increases with increasing sand thickness-footing width ratio and overburden pressure, and decreasing clay strength. It was confirmed that this variation of the angle should be taken into account in the bearing capacity calculation.

DOI CiNii
下部に粘土質を有する砂層の遠心模型支持力実験

岡村未対, 竹村次朗, 木村孟

土と基礎 45 ( 4 ) 69 - 69 1997

CiNii
Effects of shape and size of footings on the bearing capacity of sand.

岡村未対, 杢谷真一, 竹村次朗, 木村孟

土質工学会シンポジウム発表論文集 ( Jiban Hakai no Sanjigenteki Hyoka ni ... ) 141 - 148 1995.03 [Refereed]

J-GLOBAL
Dynamic behaviors of compacted sands surrounded by liquefied loose sands

A Hirooka, M Okamura, J Takemura, T Kimura

EARTHQUAKE GEOTECHNICAL ENGINEERING, VOLS 1 AND 2 681 - 686 1995 [Refereed]
Consolidation behaviour of soft clay overlain by sand under circular loading

J TAKEMURA, M OKAMURA, A HIROOKA, T KIMURA, M KAWASAKI

COMPRESSION AND CONSOLIDATION OF CLAYEY SOILS, VOL 1 205 - 210 1995 [Refereed]
Laboratory Tests for Effects of Repeated Stress on Soil Behavior at Cast-in-Place Pile Toe.

奥村文直, 岡村未対, 竹村次朗

東京工業大学土木工学科研究報告 ( 49 ) 34 - 45 1994.06

CiNii J-GLOBAL
EXCAVATION IN SOFT CLAY USING AN IN-FLIGHT EXCAVATOR

T KIMURA, J TAKEMURA, A HIROOKA, M OKAMURA, J PARK

CENTRIFUGE 94 649 - 654 1994 [Refereed]
MECHANICAL BEHAVIOUR OF INTERMEDIATE SOILS

T KIMURA, J TAKEMURA, A HIROOKA, M OKAMURA

CENTRIFUGE 94 13 - 24 1994 [Refereed]
EFFECTS OF REPEATED STRESS ON TOE RESISTANCE OF CAST-IN-PLANE CONCRETE PILES

F OKUMURA, S MOKUTANI, M OKAMURA, J TAKEMURA, T KIMURA

CENTRIFUGE 94 425 - 430 1994 [Refereed]
Study on bearing capacities of shallow footings on sand

Mitsu Okamura, Jiro Takemura, Tsutomu Kimura

Doboku Gakkai Rombun-Hokokushu/Proceedings of the Japan Society of Civil Engineers 85 - 94 1993.03

DOI

Scopus

17

Citation

(Scopus)
A study on bearing capacities of shallow footings on sand.

OKAMURA Mitsu, TAKEMURA Jiro, KIMURA Tsutomu

Doboku Gakkai Ronbunshu 1993 ( 463 ) 85 - 94 1993

　View Summary

A series of centrifuge model tests were conducted to investigate the influence of the size, shape and the depth of embedment of footings, and the ratio of grain size to footing breadth on the bearing capacity of dense sand. Strip and circular model footings were used in the tests. Bearing capacity analyses were also carried out by solving the Kötter's equations in which the stress dependency and anisotropy of the internal friction angle φ′ were taken into account. It is found that the effect of the ratio of grain size is negligible for circular footings, while for strip footings the ratio has a substantial effect. The calculated bearing capacities are in reasonable agreement with the tests results. It is confirmed that the scale effect of shallow footings on the bearing capacities are mainly caused by stress dependency of φ′.

DOI CiNii J-GLOBAL

Scopus

17

Citation

(Scopus)
The relation between dimension of a foundation and bearing capacity of a circular foundation or that of a strip foundation in sandy ground.

岡村未対, 竹村次朗, 木村たけし

土木学会年次学術講演会講演概要集第3部 47th 524 - 525 1992.09

J-GLOBAL
BEARING CAPACITIES AND DEFORMATIONS OF SAND REINFORCED WITH GEOGRIDS

J TAKEMURA, M OKAMURA, N SUEMASA, T KIMURA

EARTH REINFORCEMENT PRACTICE, VOL 1 695 - 700 1992 [Refereed]
DYNAMIC STABILITY OF A BRIDGE FOUNDATION IN A HIGH EMBANKMENT

J TAKEMURA, T KIMURA, A HIROOKA, M OKAMURA

CENTRIFUGE 91 449 - 456 1991 [Refereed]
Liquefaction resistance of sand with pre-shaking history

OKAMURA Mitsu

Int. Conf. Performance based design in earthquake geotechnical engineering 1 [Refereed] [Invited]

▼display all

Books and Other Publications

River Levee - from design to maintenance-

( Part： Joint author)

Japanese Geotechnical Society 2020.04
Model Tests and Numerical Simulations of Liquefaction and Lateral Spreading

Mitsu Okamura(Difference and Sensitivity Analyses of the LEAP-2017 Experiments)

2019
Model Tests and Numerical Simulations of Liquefaction and Lateral Spreading

Mitsu Okamura( Part： Joint author, LEAP-2017 Centrifuge Test at Ehime University)

Springer 2019
⑦ 実務に役立つ地盤工学Ｑ＆Ａ（第二巻）

地盤工学会 2009

Presentations

遠心実験による堤体直下のパイピングの観察とその発達条件の考察

露口祐輔, 岡村未対

第8回河川堤防技術シンポジウム

Presentation date： 2020.12
遠心模型実験と浸透流解析を用いた堤防直下のパイピング現象の研究

露口祐輔, 岡村未対

令和2年度地盤工学会四国支部技術研究発表会

Presentation date： 2020.11
堤防直下のパイピング進展メカニズムに関する実験と考察

露口祐輔, 岡村未対

第55回地盤工学研究発表会

Presentation date： 2020.07
干渉SARを用いた河川堤防の陥没発生以前の沈下挙動の解析

大畠慧介, 岡村未対

第55回地盤工学研究発表会

Presentation date： 2020.07
高水時に生じるパイピングとそれによる堤体表面沈下性状

今村衛, 岡村未対, 露口祐輔

第55回地盤工学研究発表会

Presentation date： 2020.07
河川堤防における排水機能付き矢板による地震時水圧低減効果に関する研究

井上直大, 岡村未対, 小野耕平

第55回地盤工学研究発表会

Presentation date： 2020.07
液状化による緩傾斜面の流動現象に関する遠心模型実験

新藤衣佐希, 岡村未対, 小野耕平

令和２年度土木学会四国支部技術研究発表会

Presentation date： 2020.05
干渉SAR経年変化解析による河川堤防の陥没発生以前の沈下挙動

大畠慧介, 岡村未対, 小野耕平

令和２年度土木学会四国支部技術研究発表会

Presentation date： 2020.05
斜面表層崩壊に影響する降雨特性に関する遠心模型実験

松原遥樹, 小野耕平, 岡村未対

令和２年度土木学会四国支部技術研究発表会

Presentation date： 2020.05
Effects of depth on the performance of gravel drains in preventing liquefaction

Presentation date： 2019.07
砕石を用いた埋設管路のスラスト防護対策効果に関する遠心模型実験

馬場口哲也, 小野耕平, 岡村未対

第54回地盤工学研究発表会

Presentation date： 2019.07
2018年西日本豪雨で被災した肱川堤防の調査

陣内尚子, 岡村未対

第54回地盤工学研究発表会

Presentation date： 2019.07
河川堤防の高水時パイピングの進展の及ぼす粒径の影響

田村元希, 岡村未対, 金子奨一郎

第54回地盤工学研究発表会

Presentation date： 2019.07
高水による堤防パイピングの遠心模型実験におけるスケール効果

露口祐輔, 田村元希, 岡村未対

第54回地盤工学研究発表会

Presentation date： 2019.07
衛星SARによる重信川陥没周辺の堤体表面の動態観測

今村衛, 山中大智, 岡村未対

第54回地盤工学研究発表会

Presentation date： 2019.07
土層強度検査棒による地盤硬さ判定と簡易動的コーン貫入試験結果との比較

山本定男, 岡村未対

第54回地盤工学研究発表会

Presentation date： 2019.07
XRAINレーダー雨量を用いた平成30年７月豪雨による愛媛県南予の斜面災害の分析

小野耕平, 森伸一郎, 岡村未対

令和元年度土木学会四国支部技術研究発表会

Presentation date： 2019.06
Influence of drain diameter on gravel drains performance as liquefaction countermeasures

Utari Minaka, Kohei Ono, Mitsu Okamura

Presentation date： 2019.06
グラベルドレーンで液状化対策下異なる地下水位の地盤の遠心模型実験

井奈波裕司, Utari Minaka, 小野耕平, 岡村未対

令和元年度土木学会四国支部技術研究発表会

Presentation date： 2019.06
液状化時における埋設パイプラインの水平変位メカニズムの検証

星川拓哉, 小野耕平, 岡村未対

令和元年度土木学会四国支部技術研究発表会

Presentation date： 2019.06
重信川堤防の陥没個所の衛星SARによる動態観察

今村衛, 山中大智, 岡村未対

令和元年度土木学会四国支部技術研究発表会

Presentation date： 2019.06
P波速度検層による不飽和状態の持続性確認(その2)

藤井直, 山田直之, 山根信幸, 矢部浩史, 小泉勝彦, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2017.08
高水の浸透による河川堤防裏法面の破壊領域

小阪佳平, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2017
矢板により水平土圧を増加させる盛土液状化対策工の数値解析

陣内尚子, 岡村未対, 高木翔平

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2017
河川堤防の高水時パイピング破壊を模擬した遠心模型実験

田村元希, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2017
加振履歴と砂地盤の液状化強度との関係と体積ひずみによる定量的評価

渡邉翔太, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2017
矢板式岸壁に対する空気注入不飽和化工法の適用

曽根照人, 小泉勝彦, 山根信幸, 深田久, 藤井直, 山浦昌之, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2016.08
高水作用を受ける均質な砂質土堤防の裏法崩壊メカニズム

笠谷亮太, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2016
堤体パイピングを模擬した遠心模型実験での表面沈下分布特性

平尾優太郎, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2016
加振履歴が液状化強度に及ぼす影響

松木園隆晟, 渡邉翔太, NELSON Fled, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2016
高速道路盛土基礎地盤への空気注入不飽和化工法適用性検討(その5)―現場実験結果と気液二相流解析の比較―

矢部浩史, 藤原斉郁, 山根信幸, 大石雅彦, 中園康平, 紙田直充, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2015.08
高速道路基礎地盤への空気注入不飽和化工法適用性検討(その6)事後調査と適用性検討のまとめ

内田純二, 藤井直, 藤原斉郁, 居場博之, 矢部浩史, 橋本欣也, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2015.08
Numerical analysis to evaluate the change in degree of saturation at different seepage pressure on partially saturated soil.

MARASINI Narayan, OKAMURA Mitsu, KASATANI Ryota

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2015
Numerical Simulation to Validate the Effectiveness of Countermeasure to Prevent Damage due to Liquefaction inside the River Dike

TRIANDINI Tamia, OKAMURA Mitsu

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2015
Increase in apparent liquefaction resistance due to drainage for a thin saturated layer

NELSON Fred, OKAMURA Mitsu

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2015
空気注入不飽和化工法の高速道路盛土への適用性検討(その5)空気注入実験の比較

山根信幸, 藤原斉郁, 矢部浩史, 大内正敏, 中園康平, 紙田直充, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2015
空気注入不飽和化工法の高速道路盛土への適用性検討(その7)事後調査と適用性検討のまとめ

内田純二, 藤井直, 藤原斉郁, 居場博之, 矢部浩史, 橋本欣也, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2015
炭酸カルシウム析出時の飽和度の違いが液状化強度特性に及ぼす影響

小阪佳平, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2015
空気注入不飽和化工法の高速道路盛土への適用性検討(その6)事後解析

大石雅彦, 藤原斉郁, 居場博之, 矢部浩史, 曽根照人, 内田純二, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2015
地盤の不飽和化による地中構造物の浮き上がり対策効果

渡邉翔太, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2015
液状化地盤の変形挙動に関する拡張型相似則の適用性に関する一斉試験

BAI Ke, 飛田哲男, 岡村未対, 竹村次朗, 井合進

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2015
外水の浸透による微小な堤体表面変位と内部状態の関係に関する実験

伊藤公孝, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2015
2011東北地方太平洋沖地震による霞ケ浦周辺堤防の液状化沈下解析

藤原憲, 陣内尚子, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2014.08
高速道路盛土基礎地盤への空気注入不飽和化工法適用性検討(その2)地盤調査と予備実験計画

藤井直, 小林真貴子, 居場博之, 深田久, 中園康平, 冨田雄一, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2014.08
高速道路盛土基礎地盤への空気注入不飽和化工法適用性検討(その3)―ダブルパッカー式注入管による注入実験―

矢部浩史, 大石雅彦, 居場博之, 高畑陽, 橋本欣也, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2014.08
高速道路盛土基礎地盤への空気注入不飽和化工法適用性検討(その4)―打込み式注入管による注入実験―

藤原斉郁, 御手洗義夫, 矢部浩史, 藤井直, 中園康平, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2014.08
高速道路盛土基礎地盤への空気注入不飽和化工法の適用性検討(その1)概要

内田純二, 紙田直充, 青木智幸, 山根信幸, 深田久, 大内正敏, 橋本欣也, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2014.08
Committee Report : The Committee on Education, JSCE

岡村未対, 原隆史

土木学会誌

Presentation date： 2014.02
Numerical simulation of centrifuge tests to evaluate the desaturation by air injection technique as a liquefaction countermeasure for existing structures.

MARASINI Narayan, OKAMURA Mitsu

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2014
Effectiveness of Sheet Pile to Reduce Crest Settlement due to Embankment Liquefaction

TRIANDINI Tamia, OKAMURA Mitsu

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2014
土中空気の溶解現象による不飽和砂地盤の飽和度経時変化に関する一次元カラム実験

笠谷亮太, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2014
空気注入不飽和化工法の高速道路盛土への適用性検討(その2)予備実験

藤井直, 小林真貴子, 居場博之, 深田久, 中園康平, 江川元幾, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2014
厚い飽和砂層の液状化発生に及ぼす加振中の排水の影響

川神英彰, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2014
空気注入不飽和化工法の高速道路盛土への適用性検討(その3)本実験計画と準備

居場博之, 高畑陽, 矢部浩史, 大石雅彦, 橋本欣也, 紙田直充, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2014
空気注入不飽和化工法の高速道路盛土への適用性検討(その4)本実験結果

藤原斉郁, 冨田雄一, 岡村未対, 御手洗義夫, 矢部浩史, 藤井直, 中園康平

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2014
空気注入不飽和化工法の高速道路盛土への適用性検討(その1)概要

内田純二, 青木智幸, 山根信幸, 深田久, 大内正敏, 橋本欣也, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2014
薄い飽和層を有する堤体内液状化判定法

林秀太朗, 井上洋, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2014
空気注入不飽和化工法の注入順序に関する現場実験

藤井直, 居場博之, 深田久, 山浦昌之, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2013.08
P波速度検層による不飽和状態の持続性確認

山田直之, 御手洗義夫, 大石雅彦, 深田久, 小泉勝彦, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2013.08
比抵抗変化率による空気注入中の飽和度の推定

居場博之, 山根信幸, 新川直利, 大内正敏, 山田直之, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2013.08
雨水浸透による盛土内飽和域形成に関する研究

岡本辰也, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2013
空気注入不飽和化工法における品質管理方法の検討

山根信幸, 磯谷修二, 藤井直, 高野仁, 岡田克寛, 岡村未対, 上田正人

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2013
盛土におけるコーン貫入抵抗比と液状化強度比の関係

林秀太朗, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2013
空気注入不飽和化工法の開発その2(事後解析)

大石雅彦, 御手洗義夫, 深田久, 山浦昌之, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2013
空気注入不飽和化工法の開発その1(現場実験)

居場博之, 新川直利, 大内正敏, 山田直之, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2013
道路盛土直下への空気注入による液状化対策効果の実験的検討

冨田雄一, 紙田直充, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2013
薄い砂層の液状化発生に及ぼす排水の影響

井上洋, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2013
遠心模型実験による鳴瀬川堤防の地震被害の再現と破壊メカニズムの検討

藤原憲, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2013
Effectiveness of Desaturation by Air Injection Technique as a Liquefaction Countermeasure for Existing Structures

MARASINI Narayan, OKAMURA Mitsu

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2013
地盤の不飽和化による液状化対策技術 : 空気注入不飽和化工法(Air-des 工法)の開発

三枝弘幸, 三好朗弘, 藤井直, 山田直之, 岡田克寛, 岡村未対

建設の施工企画

Presentation date： 2012.09
防災,安全を確保する社会基盤整備地盤の不飽和化による液状化対策技術空気注入不飽和化工法(Air‐des工法)の開発

三枝弘幸, 三好朗弘, 藤井直, 山田直之, 岡田克寛, 岡村未対

建設の施工企画

Presentation date： 2012.09
地盤工学会論文賞(和文部門)を受賞して(2)(学会の動き)

林和幸, 岡村未対, 安原英明

地盤工学会誌

Presentation date： 2012.08
空気注入不飽和化工法の開発その3:注入口配置に関する解析検討

山浦昌之, 藤井直, 浅田英幸, 岡田克寛, 新川直利, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2012.08
空気注入不飽和化工法の開発その2:注入孔間隔設定実験

藤井直, 三枝弘幸, 三好朗弘, 山田直之, 岡田克寛, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2012.08
空気注入不飽和化工法の開発その7:千葉県袖ケ浦市での現場実験(品質確認)

三枝弘幸, 三好朗弘, 藤井直, 山田直之, 岡田克寛, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2012.08
空気注入不飽和化工法の開発その5:事後調査結果

浅田英幸, 三好朗弘, 藤井直, 山浦昌之, 岡田克寛, 岡村未対, 吉田正

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2012.08
空気注入不飽和化工法の開発その1:現地実験(徳島県鳴門市)の概要

岡田克寛, 太田正規, 磯谷修二, 大内正敏, 高野仁, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2012.08
水平慣性力が硬化則・塑性ポテンシャル曲面に与える影響

田村直登, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2012.08
地盤の不飽和化が地震時の過剰間隙水圧の発生と地盤の変形に及ぼす影響

岡本辰也, 冨田雄一, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2012.08
空気注入不飽和化工法の開発その9:レベル2地震動に対する照査の一例

曽根照人, 小泉勝彦, 浅田英幸, 新川直利, 藤井直, 山浦昌之, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2012.08
道路盛土直下への空気注入による液状化対策効果の実験的検討

冨田雄一, 岡本辰也, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2012.08
空気注入不飽和化工法の開発その8:設計法の概要

小泉勝彦, 青木宏彦, 磯谷修二, 藤井直, 山浦昌之, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2012.08
空気注入不飽和化工法の開発その6:千葉県袖ケ浦市での現場実験(実験概要)

太田正規, 磯谷修二, 大内正敏, 高野仁, 岡田克寛, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2012.08
空気注入不飽和化工法の開発その4:空気注入とそのモニタリング

新川直利, 三枝弘幸, 藤井直, 山田直之, 岡田克寛, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2012.08
空気注入不飽和化工法の現地実証実験その4:事後調査

藤井直, 浅田英幸, 三好朗弘, 山浦昌之, 岡田克寛, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2012
空気注入不飽和化工法の現地実証実験その1:徳島県鳴門市での実験概要

岡田克寛, 青木宏彦, 磯谷修二, 大石雅彦, 高野仁, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2012
空気注入不飽和化工法の現地実証実験その6:千葉県袖ケ浦市での実験結果

三枝弘幸, 三好朗弘, 藤井直, 山田直之, 岡田克寛, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2012
空気注入不飽和化工法の現地実証実験その3:注入空気のモニタリング

新川直利, 三枝弘幸, 藤井直, 山田直之, 岡田克寛, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2012
空気注入不飽和化工法開発の現地実証実験その2:注入孔間隔の検討

山浦昌之, 浅田英幸, 新川直利, 藤井直, 岡田克寛, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2012
空気注入不飽和化工法を適用した場合の耐震補強工法

曽根照人, 小泉勝彦, 浅田英幸, 新川直利, 大石雅彦, 山浦昌之, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2012
堤体内の飽和領域の厚さが盛土内液状化に及ぼす影響

前田貴史, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2012
空気注入不飽和化工法の現地実証実験その5:千葉県袖ケ浦市での実験概要

太田正規, 磯谷修二, 大内正敏, 高野仁, 岡田克寛, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2012
道路盛土直下への空気注入による液状化対策効果の実験的検討

冨田雄一, 岡本辰也, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2012
ダム・堤防(2)(6.地盤と構造物,総括,<特集>第46回地盤工学研究発表会)

岡村未対

地盤工学会誌

Presentation date： 2011.12
無線加速度センサによる構造物の多点同時計測と振動の3次元可視化

中畑和之, 高本龍直, 岡村未対, 大賀水田生

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2011.08
盛土の剛性に着目した鋼材を用いた液状化対策法に関する研究

森川祐貴, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2011
地震により液状化した鉱さいダムの安定性評価

石川啓考, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2011
塑性のある細粒分を含む不飽和砂質土の液状化強度特性

竹上和希, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2011
地盤の不飽和化が液状化地盤上の盛土の沈下量に及ぼす影響

岡本辰也, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2011
地盤の液状化被害に及ぼす余震の影響

岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2011
盛土斜面の安定性評価と盛土材料の経年変化に関する研究

塚田匡史, 岡村未対, 安原英明

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2011
空気注入によって液状化対策された地盤の未改良部における水圧低下

相原聡, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2011
基礎地盤の圧密による盛土の変形が地震時の安定性に及ぼす影響

山本陸登, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM)

Presentation date： 2011
市民向け親子見学会・講演会・パネル展示(一般開放特別セッション,<特集>第45回地盤工学研究発表会)

岡村未対

地盤工学会誌

Presentation date： 2010.12
既存戸建て住宅地の耐震対策を想定した空気注入工法による液状化免震地盤の可能性

末政直晃, 明石達生, 岡村未対, 渦岡良介, 二木幹夫, 服部和徳, 永尾浩一

地盤工学研究発表会発表講演集

Presentation date： 2010.07
生体触媒を活用したカルサイト析出によるゆるい砂の力学特性の改良効果

林和幸, 安原英明, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2010.07
地盤に作用する水平慣性力が基礎の組合せ荷重の支持力に及ぼす影響

田村直登, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2010.07
大地震動に対する地盤内不飽和化による液状化抑制効果確認遠心載荷試験

永尾浩一, 明石達生, 末政直晃, 岡村未対, 渦岡良介, 二木幹夫, 服部和徳

地盤工学研究発表会発表講演集

Presentation date： 2010.07
内部応力分布の変化が地震時の盛土の安定性に与える影響

玉邑修二, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2010.07
荷重の繰返しを考慮した浅い基礎のマクロエレメントモデル

沖俊貴, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2010.07
遠心力場における飽和砂地盤への空気注入による地盤不飽和化挙動

五十嵐ひろ子, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2010.07
生体触媒を利用した炭酸カルシウム析出砂における透水・物質輸送解析

杉本知弘, 林和幸, 木下尚樹, 安原英明, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2010.07
ダム・堤防(2)((2)ダム・堤防,6.地盤と構造物,<特集>第44回地盤工学研究発表会)

岡村未対

地盤工学会誌

Presentation date： 2009.12
炭酸カルシウムの結晶析出実験による透水特性の評価

杉本知弘, 林和幸, 木下尚樹, 安原英明, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2009.07
炭酸カルシウム結晶の析出が砂の力学特性に及ぼす影響

林和幸, 只信紗也佳, 安原英明, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2009.07
遠心模型実験による土槽壁面の影響範囲に関する研究

石川啓考, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2009.07
水平加速度が組合せ荷重を受ける砂地盤の支持力に及ぼす影響

岩本一誠, 沖俊貴, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2009.07
水平加速度が砂地盤の鉛直支持力特性に与える影響

沖俊貴, 岩本一誠, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2009.07
飽和地盤への空気注入により生じる地盤のゆるみ領域に関する実験的研究

森田薫, 岡村未対, 五十嵐ひろ子

地盤工学研究発表会発表講演集

Presentation date： 2009.07
部分的に飽和した砂質盛土の動的遠心模型実験

玉邑修二, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2009.07
不飽和化による護岸の液状化対策の遠心模型実験

相原聡, 岡村未対, 井上寿幸

地盤工学研究発表会発表講演集

Presentation date： 2009.07
遠心力場における飽和砂地盤への空気注入実験と気液二相流解析

五十嵐ひろ子, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2009.07
動的性質(1)((2)動的性質,3.地盤材料-砂質土,<特集>第43回地盤工学研究発表会)

岡村未対

地盤工学会誌

Presentation date： 2008.12
土中微生物の代謝を利用した土の力学・透水特性の改良効果に関する基礎実験

林和幸, 安原英明, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2008.08
凍結サンプリング試料への小型コーン貫入抵抗とSPT‐N値の比較

桑田光章, 森重裕亮, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2008.08
河川に近接する盛土の地盤の液状化による変位量予測

玉邑修二, 林和幸, 岡村未対, 森春樹, 冨田雄一

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2008.08
重力場と遠心力場における飽和砂地盤への空気注入実験

五十嵐ひろ子, 河内義範, 岡村未対, 石丸恭平

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2008.08
空気注入による地盤の不飽和化実験

武林昌哉, 藤井直, 西田克司, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2008.08
砂斜面上帯基礎の動的支持力の実験的研究

菅田伯忠, 岡村未対, 二神治, 芳ノ内信也

地盤工学研究発表会発表講演集

Presentation date： 2008.06
空気注入による地盤不飽和化の遠心模型実験

竹村次朗, 五十嵐玲奈, 関栄, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2008.06
山岳道路盛土擁壁の支持力破壊に対する簡易な耐震点検法の検討

重松慎哉, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2008.06
構造物を有する不飽和履歴を受けた砂地盤の遠心模型振動実験

五十嵐玲奈, 井澤淳, 竹村次朗, 増田雅士, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2008.06
非塑性不飽和シルトの液状化強度特性に及ぼす空気の圧縮性とサクションの影響

野口康平, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2008.06
空気注入による地盤不飽和化の現場実験(その4)気液二相流解析によるシミュレーション

河内義範, 安原英明, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2008.06
微生物代謝を利用した地盤改良工法に関する基礎的検討

林和幸, 安原英明, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2008.06
空気注入による地盤不飽和化の現場実験(その3)比抵抗トモグラフィによる不飽和領域の計測

神宮司元治, 今里武彦, 岡村未対, 武林昌哉, 西田克司, 藤井直

地盤工学研究発表会発表講演集

Presentation date： 2008.06
組合せ荷重を受ける帯基礎のマクロエレメントモデル

古川直樹, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2008.06
空気注入による地盤不飽和化の現場実験(その2)空気の注入

藤井直, 西田克司, 武林昌哉, 岡村未対, 小松満, 森川佳太

地盤工学研究発表会発表講演集

Presentation date： 2008.06
空気注入による地盤不飽和化の現場実験(その1)全体概要

西田克司, 武林昌哉, 藤井直, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2008.06
空気注入による液状化対策の実用化に向けて

基礎工

Presentation date： 2008
空気注入による液状化対策の実用化に向けて (特集明日の基礎工)

岡村未対

基礎工

Presentation date： 2008.01
明日の基礎工空気注入による液状化対策の実用化に向けて

岡村未対

基礎工

Presentation date： 2008.01
高知県の3地点における地盤液状化強度特性

森重裕亮, 岡村未対, 河内義範, 野田巌

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2007.09
液状化対策としての空気注入による地盤不飽和化に関する基礎的実験

細川晃一, 増田雅士, 岡村未対, 五十嵐怜奈, 竹村次朗

地盤工学研究発表会発表講演集

Presentation date： 2007.06
気液二相流解析による空気注入時の地盤飽和度変化予測

森藤隆元, 安原英明, 岡村未対, 河内義範

地盤工学研究発表会発表講演集

Presentation date： 2007.06
不飽和履歴を受けた砂地盤の遠心模型液状化実験

五十嵐玲奈, 関栄, 井澤淳, 竹村次朗, 増田雅士, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2007.06
斜面上帯基礎の支持力・変形特性と地震時変位量予測法の開発

菅野靖幸, 岡村未対, 古川直樹

地盤工学研究発表会発表講演集

Presentation date： 2007.06
2006年ジョグジャ地震における地震被害と地盤特性の関係

片山雅夫, 森伸一郎, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2007.06
State of Geo-hazard Mitigation in Shikoku Region against the Nankai Earthquake

矢田部龍一, 長谷川修一, 岡村未対, BHANDARY Netra

土と基礎

Presentation date： 2007.05
空気注入によるシルト地盤の不飽和化

岡村未対, ELGAMAL Ahmed

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2006.09
サンプリング試料の動的特性について

河内義範, 岡村未対, 藤原身江子

地盤工学研究発表会発表講演集

Presentation date： 2006.06
組み合わせ荷重を受ける砂地盤上の帯基礎の荷重―変位モデル

古川直樹, 岡村未対, 二神治, 和田俊彦

地盤工学研究発表会発表講演集

Presentation date： 2006.06
6. 地盤と構造物, 7. 地盤防災(<小特集テーマ>第40回地盤工学研究発表会)

岡村未対

土と基礎

Presentation date： 2005.12
地盤災害に関する国際シンポジウム(カザフスタン)開催報告

岡村未対

土と基礎

Presentation date： 2005.08
不飽和土の液状化強度に及ぼす空気圧縮性の影響

曽我恭匡, 岡村未対, 矢田部龍一

地盤工学研究発表会発表講演集

Presentation date： 2005.06
組合せ荷重を受ける砂地盤の支持力・変形特性

堀政理, 岡村未対, 菅野泰幸

地盤工学研究発表会発表講演集

Presentation date： 2005.06
組合せ荷重を受ける斜面上帯基礎の支持力実験的研究

菅野靖幸, 岡村未対, 二神治, 堀政理

地盤工学研究発表会発表講演集

Presentation date： 2005.06
崩壊土砂の衝突に対する待受け式擁壁の変位推定手法の検討

内田太郎, 曽我部匡敏, 小山内信智, 岡村未対, 吉田望

砂防学会研究発表会概要集

Presentation date： 2005.05
液状化地盤の表層不飽和層が杭基礎に与える影響について―その1:不飽和層の地盤反力係数―

井上由美子, 田村敬一, 岡村未対, 谷本俊輔, 林和幸

地盤工学研究発表会発表講演集

Presentation date： 2004.06

　View Summary

液状化地盤における杭基礎の損傷には、表層の非液状化層の影響が大きいことが指摘されている。これは、液状化地盤の変形に伴って不飽和層の地盤も変形し、大きな土圧が杭に作用するためと考えられる。本研究では下層が飽和層、上層が不飽和層の2層地盤を作成し、杭基礎に作用する不飽和層の土圧を測定する遠心力模型実験を行い、土圧と地盤加速度を2階積分して算出した地盤変位の関係から地盤反力係数を求めた。地盤反力係数に影響する要因について検討し、不飽和層の地盤バネを深さ、相対密度、相対変位の関数として定式化した。
締固め改良地盤の不飽和液状化強度

石原雅規, 岡村未対, 田村敬一

地盤工学研究発表会発表講演集

Presentation date： 2004.06

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サンドコンパクションパイルの施工においては、砂を地盤中に押出すために高圧空気を用いる。このため、少なくとも施工直後には、改良地盤の飽和度が最大70%程度まで低下することがわかっている。本研究では、施工直後の改良地盤から採取した凍結試料を用いて非排水繰返しせん断中空ねじり試験を行い、現地盤の不飽和状態における液状化強度を求めた。本試験結果と近傍の試料を用いて実施した完全飽和状態の三軸試験および中空ねじり試験結果とを比較したところ、液状化強度が増加していることが確認できた。しかし、N値の高い地盤ほど、不飽和による液状化強度の増加の割合は小さかった。
液状化地盤の表層不飽和層が杭基礎に与える影響について(その3 応答変位法の適用性)

谷本俊輔, 田村敬一, 岡村未対, 林和幸, 井上由美子

地盤工学研究発表会発表講演集

Presentation date： 2004.06
液状化地盤の表層不飽和層が杭基礎に与える影響について(その2.互層地盤の実験)

林和幸, 田村敬一, 岡村未対, 谷本俊輔, 井上由美子

地盤工学研究発表会発表講演集

Presentation date： 2004.06

　View Summary

液状化地盤における杭基礎の損傷には、表層の非液状化層の影響が大きいことが指摘されている。これは、液状化地盤の変形に伴って不飽和層の地盤も変形し、大きな土圧が杭に作用するためと考えられる。そこで、地震時に液状化層の上にある表層不飽和層が杭基礎に与える影響を確認する実験を遠心力載荷試験装置を用いて行った。地盤は支持層、液状化層および不飽和層の3層からなる互層地盤とし、層厚を変えて3ケース作成し、地盤内には杭頭部に上部工を付けた杭模型を設置した。その結果、不飽和層厚が大きいほど杭に与える土圧が大きくなることが確認できた。
SCP改良地盤の飽和度の調査

岡村未対, 石原雅規, 田村敬一

地盤工学研究発表会発表講演集

Presentation date： 2004.06

　View Summary

サンドコンパクションパイル(SCP)工法で改良した地盤の飽和度を調査した報告によると、SCP施工直後の改良地盤の飽和度はおよそ70%~90%とかなりの程度低下している。地盤の飽和度が低下すると液状化抵抗は急激に大きくなるが、実務設計において低下した飽和度を考慮した液状化強度を用いるためには、飽和度の経時変化を調べることが必要である。SCP改良地盤の飽和度に関しては、改良直後の二,三の調査結果がこれまでに報告されているだけであり、長期的な飽和度の変化についてはほとんど知られていない。そこで、数年前にSCPで改良された地盤において原位置試験を行うとともに凍結サンプリング試料を採取し、試料の飽和度を測定したのでその結果を報告する。
G15. Ground Improvement (2)

岡村未対

Soil mechanics and foundation engineering

Presentation date： 2004.03
Effects of unsaturated sand overlying liquefied sand on a pile foundation during strong base shaking (Part 3, Analysis of piles on Winkler-spring connected to horizontally displaced ground)

Tanimoto Shunsuke, Tamura Keiichi, Okamura Mitu, Hayashi Kazuyuki, Inoue Yumiko

Proceedings of the Japan National Conference on Geotechnical Engineering

Presentation date： 2004

　View Summary

現行の道路橋示方書では液状化地盤中の橋脚杭基礎の設計に地盤変形の影響は考慮されておらず、杭に発生する応力が必ずしも適切に評価されていない可能性がある。そこで本研究では、液状化地盤中における橋梁の橋脚杭基礎の設計に、地盤変形の影響を考慮できる簡易な設計法として考えられる、静的な応答変位法の適用性の検証を行った。特に表層の非液状化層が杭に生じる応力に及ぼす影響に着目し、別報(その2)で行った実験を対象として応答変位法による計算を行った。地盤バネ定数は、別報(その1)の結果を用いた。適切な地盤変位および上部工慣性力を与えることで計算結果と実験結果はよい対応を示すことが分かった。
IMPROVEMENT OF SEISMIC REMEDIATION TECHNIQUE FOR RIVER DIKE FOUNDED ON LIQUEFIABLE SOIL

田村敬一, 岡村未対, 石原雅規, 谷本俊輔

土木研究所重点プロジェクト研究報告書平成15年度

Presentation date： 2004
A STUDY ON PRACTICAL DESIGN METHOD OF PILE FOUNDATION IN LIQUEFIED FOUNDATION SOIL CONSIDERING GROUND DEFORMATION

田村敬一, 岡村未対, 三上卓, 谷本俊輔

土木研究所重点プロジェクト研究報告書平成15年度

Presentation date： 2004
液状化地盤中の杭基礎に作用する地盤変形の影響に関する遠心力模型実験(その4 杭加速度に比例する土圧評価法の提案)

小野和行, 田村敬一, 岡村未対, 谷本俊輔, 尾山康弘

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2003.09
盛土法尻の液状化対策工に作用する地震時土圧(その2 土圧振動成分)

谷本俊輔, 岡村未対, 石原雅規, 田村敬一

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2003.09
盛土法尻の液状化対策工に作用する地震時土圧(その3 締固め工法への適用)

石原雅規, 岡村未対, 大下武志

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2003.09
液状化地盤中の杭基礎に作用する地盤変形の影響に関する遠心力模型実験(その3 群杭基礎に作用する土圧)

尾山康弘, 田村敬一, 岡村未対, 谷本俊輔, 小野和行

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2003.09
盛土法尻の液状化対策工に作用する地震時土圧(その1 土圧漸増成分)

岡村未対, 石原雅規, 田村敬一

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2003.09
地盤の流動が杭基礎に及ぼす影響に関する実験的研究(速報)

田村敬一, 岡村未対, 谷本俊輔

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2003.09
SCPで改良された砂質土地盤の26年後の飽和度

岡村未対, 石原雅規, 田村敬一

地盤工学研究発表会発表講演集

Presentation date： 2003.06

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SCPで改良された地盤の飽和度はおよそ90%以下とかなり小さく、締固の効果だけでなく飽和度が低下したことによる液状化強度の増加が期待される。しかしながら、施工直後に地盤中に含まれる空気量が長期的に低下し、飽和度が増加してゆくことも考えられる。そこで、約20年前にSCPで液状化対策を行った地盤から、凍結サンプリング法により試料を採取し、飽和度を調べた。その結果、飽和度はおよそ90%程度であり、永久ではないにしろかなりの程度長期にわたって地盤中の空気が存続することがわかった。
液状化地盤中の杭基礎に作用する地盤変形の影響に関する遠心力模型実験(その2 杭に作用する土圧の評価)

小野和行, 田村敬一, 岡村未対, 谷本俊輔

地盤工学研究発表会発表講演集

Presentation date： 2003.06

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液状化地盤中の杭基礎の被害は、上部構造物の慣性力以外に、液状化した地盤の変形により発生する土圧の影響に関連付けられると考えられている。そのため、液状化に伴う地盤変形の影響に関する研究は種々行われているが、その影響のメカニズムについては未解明な点が多く残されている。そこで本研究では、液状化地盤中の杭基礎を模擬し、地盤変形に着目した遠心力模型実験を行い、杭基礎に作用する土圧の発生メカニズムと、地盤と杭基礎との間に生じる相対運動、すなわち相対速度および相対変位、さらに杭加速度との関係について検討を行った。その結果、杭基礎に作用する土圧は、杭加速度に依存するものと、さらに相対速度および相対変位に依存するものとに区分できることを明らかにし、その評価を行った。
擁壁の地震時残留変位に基づいた耐震設計手法に関する研究

近藤益央, 田村敬一, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2003.06

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擁壁の耐震設計は、静的照査法により求めた安全率が許容安全率を満足するような断面設定で行っている。しかし、国際的基準や我が国の他の設計基準においては、仕様規程から性能規程への移行が進められているところである。本報告では、性能規程に基づく耐震設計法の1つの考え方として、根入れ効果を考慮した擁壁の変位推定法により算出した地震時残留変位量と許容残留変位量とを照査する手法を紹介する。さらに、現行設計法により設計した擁壁と本手法により設計した擁壁の断面比較や今後の課題について紹介するものである。
飽和シルト混じり砂の液状化後の変形特性

石原雅規, 岡村未対, 大下武志

地盤工学研究発表会発表講演集

Presentation date： 2003.06

　View Summary

豊浦砂および豊浦砂に非塑性シルト分(DLクレイ)を10%、20%、また塑性シルト分(藤森粘土)を10%混入した3種類の合成砂を用いて、非排水中空ねじり試験を行った。その結果、液状化強度は、非塑性シルト分10%、豊浦砂、非塑性シルト分20%、塑性シルト分10%の順となった。非塑性シルト分10%の場合には、豊浦砂の間隙にシルト粒子がつまり不のダイレイタンシーの発生が抑制される効果が、シルト分により砂粒子が分散する負の効果を上回ったために高くなったものと考えられる。しかし、液状化後の剛性回復傾向に関して言えば、豊浦砂、非塑性シルト10%、非塑性シルト20%、塑性シルト10%の順に小さくなり、砂粒子同士の接点がシルト粒子との接点に置き換わることで低下するものと推察された。
液状化地盤中の杭基礎に作用する地盤変形の影響に関する遠心力模型実験(その1 液状化地盤の挙動と土圧に関して)

谷本俊輔, 田村敬一, 岡村未対, 小野和行

地盤工学研究発表会発表講演集

Presentation date： 2003.06
護岸背後の液状化により杭基礎に作用する流動圧に関する振動台実験

谷本俊輔, 田村敬一, 岡村未対

地震工学研究発表会梗概集

Presentation date： 2003
Centrifuge Model Tests on Effects of Liquefied Soil Deformation on Pile Foundations-Part1, Behavior of Liquefied Soil and Earth Pressure Acting on a Pile

Tanimoto Shunsuke, Tamura Keiichi, Okamura Mitu, Ono Kazuyuki

Proceedings of the Japan National Conference on Geotechnical Engineering

Presentation date： 2003

　View Summary

1995年1月の兵庫県南部地震では、液状化地盤中の杭基礎の被害として、杭頭付近のみならず液状化層内部でも被害が報告されている。この液状化層内部での被害は、液状化した地盤の変形に伴う土圧の影響であることが種々の研究で報告されている。この現象を定量的に評価するためには、杭基礎および液状化地盤の運動と杭基礎に作用する土圧の関係を明らかにする必要がある。そこで本研究では、液状化地盤および杭基礎を模擬した遠心力模型実験を行った。その結果より、地盤の相対密度と透水係数による液状化地盤の挙動の違い、および杭基礎に作用する土圧の違いについて検討を行った。
重力式擁壁の地震時変位量基礎地盤の支持力特性

岡村未対, 斉藤由紀子, 田村敬一, 坪川洋友

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2002.09
盛土法尻部締固め改良地盤の地震時変形量簡易予測法

石原雅規, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2002.09
地盤の非線形性を考慮した基礎の回転変位の評価方法に関する研究

田村敬一, 岡村未対, 小林寛

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2002.09
重力式擁壁の地震時変位量擁壁の根入れ深さを考慮した地震時変位計算法の検証

斎藤由紀子, 岡村未対, 田村敬一

土木学会年次学術講演会講演概要集(CD-ROM)

Presentation date： 2002.09
砂の液状化時せん断特性の簡易モデル

石原雅規, 岡村未対

地盤工学研究発表会発表講演集

Presentation date： 2002.06
静的締固め工法により改良された地盤の液状化強度分布

岡村未対, 石原雅規

地盤工学研究発表会発表講演集

Presentation date： 2002.06
複合構造物・他(動的問題1,2,補強土1,2)(6.地盤と構造物)

岡村未対

土と基礎

Presentation date： 2001.12
重力式擁壁の地震時変位予測法の開発

斉藤由紀子, 岡村未対, 松尾修

日本道路会議論文集

Presentation date： 2001.10
重力式擁壁の地震時挙動とその予測法について擁壁の滑動・沈下・回転を考慮した地震時変位計算法の検証

斉藤由紀子, 松尾修, 岡村未対, 中村伸也

土木学会年次学術講演会講演概要集第3部

Presentation date： 2001.09
盛土構造物の耐震対策効果に関する遠心模型実験のシミュレーション

高野令男, 岡村未対, 松尾修

土木学会年次学術講演会講演概要集第3部

Presentation date： 2001.09
重力式擁壁の地震挙動とその予測法について擁壁の水平・鉛直・回転変位予測法

岡村未対, 松尾修

土木学会年次学術講演会講演概要集第3部

Presentation date： 2001.09
液状化性地盤上の鋼矢板二重仮締切の動的遠心模型実験

岡村未対, 松尾修

地盤工学研究発表会発表講演集

Presentation date： 2001.05
地盤の液状化による盛土沈下対策工(締固め工法)の効果

岡村未対, 田本修一, 松尾修

地盤工学研究発表会発表講演集

Presentation date： 2001.05
弾塑性FEMの結果に及ぼす入力パラメータのバラツキの影響と結果の信頼性

高野令男, 岡村未対, 松尾修

地震工学研究発表会講演論文集

Presentation date： 2001

　View Summary

近年、動的有限要素解析法が実務にも取り入れられてきた。このような解析法を実務設計に用いる場合、結果の信頼性評価を行って適切な安全率あるいは部分係数を決める必要がある。結果の信頼性に影響を及ぼす要因として、解析手法自体の不確実さ、入力パラメータ (土質定数等) の不確実さが上げられる。そこで本研究では、動的有限要素解析コード (LIQCA) を用い、液状化地盤上の盛土の地震時変形解析を行い、入力パラメータのバラツキが沈下量に及ぼす影響を調べ為また、解析結果に対して信頼性の評価を試みた。
International Workshop on Geotechnology for Natural Hazards

Okamura Mitsu

Soil mechanics and foundation engineering

Presentation date： 2000.03
地盤工学会研究奨励賞を受賞して[1]

岡村未対

土と基礎

Presentation date： 1999.08
Simulation of centrifugal and dynamic model experiment of banking by effective stress analysis method.

岡村未対, 松尾修

土木学会年次学術講演会講演概要集第3部

Presentation date： 1999.08
Centrifuge modeling of embankments resting on liquefiable subsoil.

岡村未対, 田本修一, 松尾修

地盤工学研究発表会発表講演集

Presentation date： 1999.06
遠心模型実験に関する国際会議 (IS-TOKYO'98) 開催報告

岡村未対, 堀越研一, 片桐雅明, 玉手聡

土と基礎

Presentation date： 1999.03
A study on p-y curves of pile in a sandy slope.

岡本道孝, 神田政幸, 岡村未対, 竹村次朗

土木学会年次学術講演会講演概要集第3部

Presentation date： 1997.09
Effects of Initial Void Ratio and Stress History on Mechanical Characteristics of Low Plastic Intermediate Soils.

岡村未対, 竹村次朗, 桑野二郎, LU Y D

地盤工学研究発表会発表講演集

Presentation date： 1997.05
Prediction of load-settlement behavior of circular footings on compressive sandy soil.

佐原史浩, 岡村未対, 日下部治

地盤工学研究発表会発表講演集

Presentation date： 1997.05
Effects of embedment length and ground condition on performance of soft clay with sheet pile subject to fill loading.

石井裕泰, 岡村未対, 竹村次朗, 日下部治

地盤工学研究発表会発表講演集

Presentation date： 1997.05
Microscopic observation of particle behavior in shear zone of densed sand.

米今智信, 高橋章浩, 岡村未対, 日下部治

地盤工学研究発表会発表講演集

Presentation date： 1997.05
Stability of landing pier with steel piles subjected to lateral flow of ground caused by liquefaction during earthquake.

川口喜孝, 岡村未対, 高橋章浩, 竹村次朗

地盤工学研究発表会発表講演集

Presentation date： 1997.05
Centrifuge modelling on test embankment on soft clay with sheet pile.

石井裕泰, 小沢一喜, 岡村未対, 竹村次朗, 日下部治

地盤工学研究発表会発表講演集

Presentation date： 1997.05
Centrifuge tests of lateral bearing capacity of single piles in unconsolidated cohesive soil.

NGUYEN T N, 安元健二, 岡村未対, 日下部治

地盤工学研究発表会発表講演集

Presentation date： 1997.05
Centrifuge Model Tests of Embankment on Soft Clay with Sheet Pile Wall Reinforcement against Settlement of Adjacent Ground.

竹村次朗, 石井裕泰, 岡村未対, 高橋章浩, 日下部治

東京工業大学土木工学科研究報告

Presentation date： 1997.03
The effect of sheet pile construction as a settlement countermeasure for the soft clay ground subjected to embankment loading.

石井裕泰, 岡村未対, 木村孟, 竹村次朗

土木学会年次学術講演会講演概要集第3部

Presentation date： 1996.09
Horizontal bearing force characteristic of foundation based on cement improved ground of low strength column.

安元健二, 佐原史浩, 岡村未対, 桑野二郎

土木学会年次学術講演会講演概要集第3部

Presentation date： 1996.09
An Experimental Study on p-y Curves of Piles in Sand.

金縄知樹, 岡村未対, 神田政幸, 竹村次朗, 桑野二郎

地盤工学研究発表会発表講演集

Presentation date： 1996.05
Lateral loading tests of a single pile in sand using geotechnical centrifuge.

金縄知樹, 神田政幸, 岡村未対, 竹村次朗, 桑野二郎

地盤工学研究発表会発表講演集

Presentation date： 1996.05
Evaluation of bearing capacities of footing on sand subjected eccentric load.

三原淳慎, 岡村未対, 竹村次朗, 桑野二郎, 木村孟

地盤工学研究発表会発表講演集

Presentation date： 1996.05
Effects of Consolidation Stress on Drained Shear Characteristics of Low Plastic Soils.

久田成昭, 桑野二郎, 竹村次朗, 岡村未対, RIKU U

地盤工学研究発表会発表講演集

Presentation date： 1996.05
Centrifuge model tests on vertical cuts with sheet pile wall in overconsolidated clay.

SOU S, 秋畑純一, 岡村未対, 竹村次朗, 木村孟

地盤工学研究発表会発表講演集

Presentation date： 1996.05
An experimental study on the bearing capacities of footings on sand under eccentric loading.

岡村未対, 三原淳慎, 竹村次朗, 桑野二郎

地盤工学研究発表会発表講演集

Presentation date： 1996.05
軟弱地盤における土留め掘削時の安定性に及ぼす根入れの影響

秋畑純一, 曹志浜, 岡村未対, 竹村次朗

土木学会年次学術講演会講演概要集第3部

Presentation date： 1995.09
Effects of shape of footings on bearing capacitites of sand.

杢谷真一, 岡村未対, 竹村次朗, 木村孟

土質工学研究発表会発表講演集

Presentation date： 1995.05
A study on settlement of clay layer which is applied cyclic loading.

石井裕泰, 三原淳慎, 岡村未対, 桑野二郎, 竹村次朗

土質工学研究発表会発表講演集

Presentation date： 1995.05
Deformation of intermediate soils during loading.

渡部要一, 桑野二郎, 岡村未対, 竹村次朗

土質工学研究発表会発表講演集

Presentation date： 1995.05
Centrifuge model tests on excavation in a stacked drift tunnel in saturated soils.

清藤幹雄, 野城一栄, 岡村未対, 桑野二郎, 尾上篤生

土質工学研究発表会発表講演集

Presentation date： 1995.05
Stability on vertical excavations with sheet pile wall in soft clay.

安部勝也, SOU S, 岡村未対, 竹村次朗, 木村孟

土質工学研究発表会発表講演集

Presentation date： 1995.05
Effects of repeated loading on bearing capacities and settlement of piles.

杢谷信一, 岡村未対, 竹村次朗, 奥村文直

土質工学研究発表会発表講演集

Presentation date： 1994.05
Stability of underground structure in sand subjected to uplift force.

野城一栄, 塩梅崇, 岡村未対, 竹村次朗, 木村孟

土質工学研究発表会発表講演集

Presentation date： 1994.05
On the Behavior of Stacked-drift type Tunnels during Core Excavation.

酒井貴之, 岡村未対, 竹村次朗, 木村孟, 尾上篤生

土質工学研究発表会発表講演集

Presentation date： 1994.05
Consolidation of Two Layered Soil under Circular Loading.

川崎将生, 三原淳慎, 岡村未対, 竹村次朗, 木村孟

土質工学研究発表会発表講演集

Presentation date： 1994.05
A study on bearing capacities and deformations of sand reinforced with geogrid, overlying weak sand.

三原淳慎, 岡村未対, 竹村次朗

土質工学研究発表会発表講演集

Presentation date： 1994.05
Loading rate effects on bearing capacities and deformations of intermidiate soils.

PARK J, 岡村未対, 竹村次朗, 木村孟

土質工学研究発表会発表講演集

Presentation date： 1994.05
繰り返し載荷を受ける砂地盤中の杭の支持力・変形特性

川崎将生, 岡村未対, 竹村次朗, 奥村文直

土木学会年次学術講演会講演概要集第3部

Presentation date： 1993.09
A study on bearing capacity of circular footings on sand overlying clay.

岡村未対, 川崎将生, 竹村次朗, 木村孟, 末政直晃

土質工学研究発表会発表講演集

Presentation date： 1993.05
A failure mechanism of sand layers reinforced with geogrid due to strip loading.

岡村未対, 末政直晃, 竹村次朗, 木村孟

土質工学研究発表会発表講演集

Presentation date： 1992.05
Bearing capacity of sand layer overlying clay.

川崎将生, 岡村未対, 竹村次朗, 木村孟

土質工学研究発表会発表講演集

Presentation date： 1992.05
Bearing characteristics of a sand layer lying between soft clay layers.

岡村未対, 竹村次朗, 神田政幸, 木村孟

土木学会年次学術講演会講演概要集第3部

Presentation date： 1991.09
Bearing capacities and deformations of low plastic soils.

PARK J, 岡村未対, 木村孟, 竹村次朗

土質工学研究発表会発表講演集

Presentation date： 1991.06
Bearing capacities of a sand layer sandwiched by clay.

神田政幸, 岡村未対, 末政直晃, 木村孟

土質工学研究発表会発表講演集

Presentation date： 1991.06
An investigation on the bearing capacity of sand layers reinforced with geogrid.

岡村未対, 末政直晃, 竹村次朗, 木村孟

土質工学研究発表会発表講演集

Presentation date： 1991.06
Influence of strain velocity on shear property of low plasticity cohesive soil.

中薗裕, 岡村未対, 竹村次朗, 中瀬明男

土木学会年次学術講演会講演概要集第3部

Presentation date： 1990.09
A study of bearing capacities and deformations for sand overlying clay ground.

岡村未対, 竹村次朗, 木村孟

土質工学研究発表会発表講演集

Presentation date： 1990.05
Failure mechanism and bearing capacities of sand under a cylindrical footing.

岡村未対, 木村孟, 斉藤邦夫, 竹村次朗

土質工学研究発表会発表講演集

Presentation date： 1988.05
2018年スラウェシ島地震での大規模地盤流動域から採取した砂の単調及び繰返しせん断特性

田中涼太郎, 岡村未対, 小野耕平

第55回地盤工学研究発表会

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Research Projects

Remedial measures for river levees against piping-induced breach

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2023.04

-

2027.03
土の膠着物質サイズ制御システムの構築と土の力学特性・地下水質改善効果向上への応用

日本学術振興会科学研究費助成事業

Project Year :

2023.04

-

2027.03

林和幸, 角田範義, 岡村未対, 岸本昇, 安原英明
砂の年代効果の実験時間5000倍圧縮の実現～結晶のオストワルド熟成の利用～

日本学術振興会科学研究費助成事業

Project Year :

2022.06

-

2025.03

林和幸, 岡村未対
Cause Investigation and Mitigation Method for Long Distance Fluidized Flow in Gently Sloped Soils during Inland Earthquake

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Project Year :

2020.04

-

2023.03
炭酸カルシウム法地盤改良技術を使った地下水中の金属資源捕捉回収システムの開発

日本学術振興会科学研究費助成事業基盤研究(B)

Project Year :

2020.04

-

2023.03

林和幸, 角田範義, 岡村未対, 安原英明

　View Summary

地中に炭酸カルシウムを沈殿させて築く透過性地中壁の「地下水中の金属固定集積機能」を明らかにするため，間隙の状態をフラスコ内で再現し，金属イオン濃度の経時変化を調べるバッチ試験を行った．対象とする金属は，事前に行った化学平衡計算で良好な結果が得られたマンガン，ニッケル，コバルト，亜鉛，および鉛の5種類とし，それぞれの塩化物を溶質とする水溶液に炭酸カルシウム粉末を投入し，試験期間中連続的に攪拌した．その結果，砂質量に対する炭酸カルシウム含有率0.5～2.0%の範囲を想定したバッチ試験において，いずれの炭酸カルシウム含有率においても95%以上の重金属が沈殿物として補足され，同時に炭酸カルシウム中のカルシウムイオンが放出されその濃度が上昇する結果が得られた．重金属およびカルシウムのイオン濃度と時間の関係を表す曲線には，ほとんどのケースで2つの凸(または凹)が現れたことから，重金属が2つの異なるメカニズムで捕捉されていると推察された．また，溶出したカルシウムイオンの濃度は，捕捉された重金属イオン濃度の1.20～2.8倍の範囲にあることから，想定された1:1のイオン交換とは異なるメカニズムが作用して沈殿物が生成されたと推察された．
次に，重金属水溶液が透過性地中壁に滞留する時間と地中壁の重金属補足性能の関係を明らかにするため，炭酸カルシウムを1%含有する砂のカラム(Φ50mm，H100mm)を作成し，マンガン，ニッケル，コバルトのそれぞれの水溶液を段階的に通水するカラム通水試験を実施した．その結果，間隙での滞留時間が1日程度と短い場合には，重金属捕捉が炭酸カルシウム結晶表面のみにとどまり，高い捕捉率を得るには重金属イオンが炭酸カルシウム結晶内部に侵入するために数日の時間が必要となることが分かった．
河川堤防のパイピングメカニズム解明と維持管理法のパラダイムシフトに向けた研究

日本学術振興会科学研究費助成事業基盤研究(A)

Project Year :

2019.04

-

2023.03

岡村未対, 泉典洋, 前田健一, 全邦釘

　View Summary

2019年度の研究で，以下のことを実施し，ほぼ期待通りの成果を上げた。
■パイプ内の水の流れとそれによるパイプ孔壁の侵食とパイプ内土砂運搬の現象を解明するため，高速度カメラでパイプ内を観測し，さらに3次元浸透流解析を行った。実験は40gの遠心加速度場及び重力場で行い，粒径や模型サイズを変えた実験を組み合わせ，来年度の相似則の検討に向けたデータも蓄積した。
■堤体表面形状からパイピング部を高速自動探査する方法の開発：高水により噴砂が発生した堤防の堤体表面形状をUAVからの写真撮影とSfMで構築したDEMにより詳細に測定する。地表面変位分布からパイピングの位置，規模を推定し，現場での噴砂状況（位置，噴砂ボリューム）と比較することを近年噴砂が発生した那賀川，肱川，重信川堤防について行い，地表面の変位分布からパイピング部の推定をする方法の構築に資する成果を得た。
において実施する
■パイピング部を特定するための原位置地盤調査法の開発：実地盤におけるパイピング部やそれによる地盤のゆるみ領域の厚さは1cm～10cm程度と薄く，面的にも幅は数十cm程度と狭く，そこでの土の強度はほぼゼロである。このような箇所を直接的に検出するために，貫入装置の直径が約2cmと小さく，貫入ロッド周面摩擦の影響を排除するため，先端に高感度ロードセルを取り付け，さらにレキ当たりなどで簡単に壊れない強靭性を有する試験機を開発した。多数の貫入を行うため，バイブロ貫入機を用い２～３人作業で40箇所/日の試験法を開発し，２カ所のパイピング発生現場にて試験を実施し適用性を確認した。
河川堤防のパイピングメカニズムと維持管理法

JSPS 科学研究費補助金

Project Year :

2019.04

-

2023.03

岡村未対
令和元年台風19号及び台風21号による広域災害に関する総合研究

日本学術振興会科学研究費助成事業特別研究促進費

Project Year :

2019.12

-

2020.03

二瓶泰雄, 中北英一, 竹見哲也, 山田朋人, 三隅良平, 飯塚聡, 鈴木真一, 仲江川敏之, 柳瀬亘, 立川康人, 田中茂信, 佐山敬洋, 田中智大, 朝位孝二, 前野詩朗, 田中仁, 吉谷純一, 田中規夫, 泉典洋, 矢野真一郎, 森脇亮, 赤松良久, 内田龍彦, 重枝未玲, 岩崎理樹, 清水義彦, 小山毅, 長谷川兼一, 西嶋一欽, 藤本郷史, 毛利栄征, 前田健一, 岡村未対, 卜部厚志, 森口周二, 蝦名裕一, 松四雄騎, 王功輝, 竹林洋史, 鈴木素之, 田島芳満, 佐々木淳, 信岡尚道, 森信人, 有川太郎, 鈴木崇之, 下園武範, 松井正宏, 小林文明, 畑山満則, 牛山素行, 佐藤健, 梶谷義雄

　View Summary

令和元年台風19号及び台風21号（低気圧）による広域災害の被害状況・メカニズムの全容を明らかにすることを目的とした調査研究を進めた．ここでは，①台風・低気圧による豪雨・流出現象の気象学的解明，②広域にわたる洪水氾濫災害を引き起こしたメカニズムの解明，③多発した土砂災害・土構造物破壊におけるメカニズムの解明，④強風や高潮による被害実態の解明，⑤住民の避難行動の実態と防災情報の伝達状況の把握，の5つのテーマに焦点を絞って研究を行った．その結果，①気象レーダーなど様々な降水・気象観測データを用いて，台風・低気圧の構造や極端豪雨の発生メカニズムの一端を明らかにした．また，今次台風による降雨・流量の水文発生頻度を明らかにした．②洪水氾濫被害に対して，河川工学の見地から氾濫の発生メカニズムや被害拡大の要因の一端を調べた．洪水による建築物の被害を，防災，河川工学，構造，材料，環境の観点から分析した．③現地踏査や原位置試験，UAV調査により，斜面崩壊・土石流などの発生状況，河川堤防や道路等の土構造物の被災状況や発生メカニズムを把握した．④駿河湾，相模湾，東京湾，外房の沿岸部における台風19号に伴う高潮・高波による浸水や海岸構造物や家屋の直接的な被災状況を調べると共に，河口部における水位上昇に伴う影響評価を行った．また，同年の台風15号や2018年台風21号，24号などの過去の台風に伴う高潮・高波災害との比較を通じ，本災害の特徴を明らかにした．台風19号による強風被害の実態を調査し，今後の気象災害低減に資する情報をまとめた．⑤今次台風における大規模な人的被害の発生要因や避難者の行動，避難所での対応に関する実態を明らかにした．
Collaborative research: Validation of centrifuge and numerical modeling for dynamic behavior of civil infrastructure under earthquakes

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

Project Year :

2017.04

-

2020.03

Tobita Tetsuo

　View Summary

The purpose of this study was to evaluate the disaster prediction accuracy of both centrifugal experiments and numerical methods by simultaneously conducting experiments and analyses by multiple research institutes in Japan and overseas for, and to further improve accuracy. The target of the experiment and numerical analysis was the saturated sand ground under dynamic excitations. The correlation between the relative density of the ground and the input acceleration level was investigated for response acceleration, excess pore water pressure, and ground deformation. As a result of joint simultaneous experiments conducted by 11 international experimental institutions, it was found that the experimental results such as the amount of ground deformation for each institute are in harmony with the overall tendency in a wider range of relative density and input acceleration level. The validity of the model experiment was confirmed.
Internal Erosion in a Foundation Soil under a Sand Levee and its Manifestation on the Levee Surface

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Challenging Research (Exploratory)

Project Year :

2017.06

-

2019.03

Mitsu Okamura

　View Summary

River levees occasionally fail during flooding because of the mechanics of internal erosion or piping within or below the levees. Current inspection methods cannot detect the pipes until it manifests itself at the exterior sur-face. There is a strong need for non-destructive techniques that can identify internal damage. In this study it was found that specific deformation pattern appears on the surface of levees just above pipes. A method was established for estimating the size and location of the pipes based on the characteristic shape of the de-formed slope. The method was applied to levees, where significant sand boils occurred at the levee toe during recent flooding events. In addition, a number of mini-ram soundings were conducted at small intervals to identify the pipe locations in a more direct manner. It was confirmed that the penetration tests were effective in detecting the pipe locations. The detected locations compared well with those estimated from the surface topography.
Aging effects on liquefaction resistance of sands and relevant index parameters

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Project Year :

2016.04

-

2019.03

Mitsu Okamura

　View Summary

Repeated small shaking events due to earthquakes significantly enhance liquefaction resistance of soils. This study investigates the pre-shearing effects on the liquefaction resistance (RL) through laboratory tests and centrifuge tests. An attempt was made to explain the effects quantitatively with a single index parameter of the volumetric strain caused by pre-shearing. It was confirmed from triaxial tests that the RL of pre-sheared sand uniquely increased with increasing volumetric strain during the pre-shearing. To examine the pre-shaking effects on the RL of sand under a level ground condition, centrifuge tests were conducted. Sand models were subjected to small shaking events repeatedly, which were weak enough not to cause liquefaction. At the end of the test, the sand was subjected to a strong shaking event. The relationship between RL ratio of the ground and volumetric strain that occurred in the pre-shaking events coincides with that obtained from the triaxial tests.
堤防のパイピング

文部科学省科学研究費補助金

Project Year :

2017.04

-

2019.03

岡村未対
液状化年代効果

文科省科学研究費助成金

Project Year :

2016.04

-

2019.03

岡村未対
Real time levee inspection to detect progress of piping holes during flooding based on settlement of levee surface

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research

Project Year :

2015.04

-

2017.03

Okamura Mitsu, Shinsei Akira, Yasunaga Kazuo, Tamaoka Ryoichi

　View Summary

This study, a series of centrifuge tests was conducted first to investigate settlement profile of river levee slope due to loss of soil from the piping inside the levee. Relationship between settlement profile and size and location of piping holes is established, which makes it possible to identify the piping based only on settlement of slope surface. The possible piping holes of Kinugawa river levee, in which sand was ejected from levee toe during the flooding event in 2015, are estimated using the relation. At the same site, penetration tests are conducted to identify the locations where the soil loosened possibly by piping during the flooding. It was found that the location estimated by the relation coincided with that detected by the penetration tests, confirming the validity of the relationship.
Multiple centrifuge tests and numerical analyses for geotechnical hazard prediction based on generalized scaling law

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Project Year :

2014.04

-

2017.03

Iai Susumu, OZUTSUMI Osamu, UEDA Kyohei, SAWADA Shunichi, UEMURA Kazuaki, MANZARI Majid, ZEGHAL Mourad, KUTTER Bruce, MADABUSHI Gopal

　View Summary

Geo-hazards induced by strong earthquakes, including liquefaction, have been evaluated by centrifuge model tests by scaling spacial and time factors into smaller model scales. The objective of this research is to achieve a high precision in geo-hazards evaluation by applying the generalized scaling law, which expands the limitation of scaling factor (1:50) in the conventional centrifuge model tests into the scaling factors ranging from 1:100 to 1:1000. By performing parallel centrifuge tests by three research groups and also running parallel numerical analyses by four research groups, including overseas institutions, referring to the same prototype geo-hazards, this research project has achieved the high precision in geo-hazards evaluation.
研究プロジェクトを通じた国際技術者養成プログラム

JASSO ① 海外留学支援制度

Project Year :

2016.06

-

2017.03

岡村未対
河川堤防の安全性評価技術の向上

河川財団河川整備基金

Project Year :

2016.04

-

2017.03

岡村未対
堤防表面変位

文科省科学研究費補助金

Project Year :

2015.04

-

2017.03

岡村未対
カトマンズ盆地における地盤液状化の実態解明と液状化強度特性および揺れや

JST J-RAPID

Project Year :

2015.08

-

2016.06

岡村未対
Seepage and overtopping performance of deformed levee after earthquake

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Project Year :

2013.04

-

2016.03

Uzuoka Ryosuke, HARA Tadashi, SENTO Noriaki, OKAMURA Mitsu, YAMANAKA Minoru, YAMAKAWA Yuki, SUZUKI Hisashi, UENO Katsutoshi, MUTO Yasunori, IKAMI Yasuhiro, RYU Jinseok, DAIKOKU Yuki, KAWASAKI Takamasa, ITO Kei

　View Summary

During the 2011 off the Pacific coast of Tohoku earthquake, coast and river levees caught the influence of external force by tsunami as well as earthquake. However there were few studies on seepage and overtopping performance of damaged levees after earthquake against tsunami and rainfall. In this study, we investigated seepage performance of deformed levees after shaking and evaluated durability of deformed levee under plural external forces such as earthquake and tsunami using centrifugal model tests and numerical simulations. We examined the effects of some experimental parameters such as input motions and water rising velocity on the seepage performance. The centrifugal model tests showed that seismic deformation changed the seepage performance of levees, and progressive failure during seepage might occur at the downstream side of levee slope. The numerical simulations showed that factors except for configuration change might affect the seepage performance of deformed levee.
Developing a extremely cost effective liquefaction countermeasure

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Project Year :

2013.04

-

2016.03

Okamura Mitsu, YASUHARA Hideaki, HAYASHI Kazuyuki

　View Summary

In order to obtain soil samples from the foundation soil just below a highway embankment where in-situ air injection had been conducted to desaturate the ground as a liquefaction countermeasure, a simple and cheap ground freezing method has been developed. Frozen samples will be taken from the ground wi the method in a near future to directly measure distribution of degree of saturation.
The durability of the desaturated soils, which is one of the concerns of the technique, depends on the sustainability of the injected air in the soil pore. To evaluate the evolution in degree of saturation (which ensures the longevity of injected air) numerical simulations were conducted considering advection and the molecular diffusion process of mass transfer by using the multiphase flow simulation model (TOUGH2) based on the finite difference method (FDM). It is confirmed that the unsaturated condition of the site will last more than 200 years.
Study on combined geotechnical hazards in wide coastal area around mega-cities

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Project Year :

2011.04

-

2014.03

IAI Susumu, TOBITA Tetsuo, SUGANO Takahiro, TOWHATA Ikuo, UZUOKA Ryosuke, OKAMURA Mitsu, ICHII Koji, OHTA Hideki

　View Summary

This study focuses on time factor in remediation of coastal areas in Osaka Bay area asu as (1) combined failure of geotechnical structures due to Tsunami: progressive failure due to repeated arrivals of Tsunami, (2) pore water flow and pressure dissipation: progress of failure due to excess pore water pressure generation due to Tsunami and reduction effect on failure due to dissipation of pore water pressure, (3) mitigation measures and life cycle costs: progressive implementation of remediation measures. The results of the study lead to a methodology for evaluation of vulnerability in wide area and implementation of mitigation measures.
Development of cost effective liquefaction countermeasure technique by air injection and evaluation of its impact to on geo-environment.

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Project Year :

2009

-

2012

OKAMURA Mitsu, YASUHARA Hideaki

　View Summary

Objective of this research is to develop a cost effective liquefaction countermeasure technique by air injection and to propose a design and execution manual. The following items are in particularly studied.
(1) Mechanism of instability of existing structures when foundation soil immediately below the structures is desaturated.
(2) Evaluation of effectiveness to reduce deformation and settlement during strong base shaking.
(3) Relationship between liquefaction strength ration and volumetric strain for silt and silt mixed sand.
(4) A design and execution manual is published.
An integrated study of rainfall-and earthquake-induced disasters in the Himalayan watershed for a strategic development of disaster education system in the region

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Project Year :

2009

-

2011

YATABE Ryuichi, OKAMURA Mitsu, NETRA Bhandary, HASEGAWA Shuichi, MORIWAKI Ryo

　View Summary

Two major research achievements through this project are : 1) a detailed study of ground response analysis in Kathmandu Valley of Nepal using microtremor survey and 2) landslide mapping and hazard assessment in Lesser Himalayan mountains of central Nepal. Additionally, in the three years of research period, initiatives have been taken towards adopting school disaster education in Primary and Secondary schools of Nepal along with organization of regular professional meetings to discuss various aspects of disaster management through school disaster education. Moreover, a network of disaster professionals and policy makers not only in Nepal but also in the South Asian nations through the SAARC(South Asian Association for Regional Cooperation) Disaster Management Center(SDMC) is in building process, which can be expected to integrate the disaster management issues, particularly in the field of rainfall-and earthquake-induced disasters in the whole Himalayan Region.
Transport Route Hazard Assessment for Post-Nankai Earthquake Reconstruction Support to Potential Areas of Isolation and Conservation of Cultural Heritage

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Project Year :

2008

-

2010

YATABE Ryuichi, OKAMURA Mitsu, MORI Shinichiro, HASEGAWA Suichi, BHANDARY Netra, HATO Eiji

　View Summary

Shikoku fears heavy damage during the Nankai Earthquake, which is due to hit this region in next 30-50 years. Although tsunami is particularly feared of, the potentials of geo-disasters are equally important. Not only liquefaction of coastal areas in Kochi and Tokushima plains and landslides in mountainous areas, but discontinued road network is also expected to affect people's life in the disaster-hit areas. If the Nankai Earthquake takes place right at present, the reconstruction of Route 32 is supposed take more than one month, that of Route 33 is estimated at a few weeks, and that for Route 56 and JR Yosan Line is yet to be estimated. This will cause isolation of Kochi Prefecture from terrestrial-route perspectives. At the same time, human settlements over the remote mountains will also be isolated, and the scattered cultural heritage sites of Shikoku will also be damaged. All this in background, hazard assessment of the road network in Shikoku during the Nankai Earthquake has been made and hazard maps have been prepared in this study. The ground dynamics of the cultural heritages sites, particularly, the Shikoku 88-Pilgrimage Temples, has also been investigated and elucidated with the help of microtremor survey.
Earthquake Disaster Mitigation and Conservation of World Cultural Heritages in Nepal-in case of an

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Project Year :

2006

-

2008

YATABE Ryuichi, OKAMURA Mitsu, NETRA Bhandary, MORI Shinichiro, HASEGAWA Shuichi, HATO Eiji, BHATTARAI DEEPAK, SHREST HAHARI KRISHNA, UPRETI BISHAL NATH
Development of novel ground improvement technique of soil desaturating by air injection

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Project Year :

2005

-

2007

OKAMURA Mitsu, MORI Shin-ichiro, TAKEMURA Jiro

　View Summary

Measures preventing earthquake-induced soil liquefaction are of significant importance to mitigate the liquefaction hazards. However, execution costs of currently available technique are generically expensive. An air-injection technique may be a simple, inexpensive alternative-this leads the saturated soils to the desaturated by injecting pressurized air bubbles, resulting in a higher liquefaction strength and the lower susceptibility This project aims at investigate Mowing items which are essential to develop a novel liquefaction countermeasure technique of soil desaturation by air injection.
(1)Influential factors of the liquefaction resistance of partially saturated sand are derived from theoretical consideration and effects of the factors are examined through a series of triaxial tests. It was confirmed that the degree of saturation has a significant effect on the liquefaction resistance. It also appeared that the liquefaction resistance depends on the initial confining pressure and the initial pore pressure; the higher the confining pressure and the lower the initial pore pressure, the higher the liquefaction resistance of partially saturated sand. A unique relationship between liquefaction resistance ratios and the potential volumetric strain was found, which enable to estimate the liquefaction resistance of partially saturated sand with the effects of the three factors taken into account.
(2)A series of centrifuge tests was conducted to investigate seismic behavior of desaturated soil-structure system and effects of desaturation as a liquefaction countermeasure technique. It was confirmed that settlements of the structure on partially saturated sand is much smaller than that of the saturated sand.
(3)A series of model tests that simulate air injection into saturated soils using air-injection probes, was conducted to investigate the desaturation mechanism during air injection It was found that the evolution of desaturation is strongly controlled by the vertical and horizontal permeabilities of the soil as well as the injection air pressure. The numerical analyses using a multiphase flow simulator is conducted to describe the evolution of the soil desaturation obtained from the measurements, and to examine the applicability of the model as a prediction tool enabling the evolution of desaturation in situ to be followed with time and space. Predictions show a good agreement with the measurements regarding the rates, magnitudes, distribution of degree of saturation, and airflow rates.
A Study on the Mechanism of Large-scale Sediment Disasters in Hindukush Himalayan Watershed and Their Preventive Measures

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Project Year :

2003

-

2005

YATABE Ryuichi, BHANDARY Netra, TAKAHASHI Jiro, OKAMURA Mitsu, HATO Eiji, KITAGAWA Ryuji

　View Summary

This investigative research is related to the mechanism of large-scale landslide and slope failure disasters in Himalayan watersheds and an integrated approach to their prevention. The fields for this study were selected to be disaster management system in Nepal and the landslide zones along major highways in central Nepal. The Himalayan watershed is the most active mountain building zone in the world, which has resulted in formation of steep mountains. For this reason, landslides and related disasters do occur very frequently. The results and findings of this study are supposed to enhance the efforts of landslide disaster mitigation in the Himalayan watersheds.
At first, this study attempted to propose an integrated approach to landslide disaster management in Nepal as a developing country and test-implemented it. This involved various activities from disaster education to awareness enhancement. For example, disaster education for school level students and teachers in the form of workshops and printed material, disaster seminars for engineers and technicians and networking, disaster related research efforts involving undergraduate and graduate students and networking, media-based disaster awareness raising programs. These programs involved a large number of people from primary school children to general public resulting in a nation-wide human network. School education and media-based (memorandum of understanding has been signed with Nepal's only national TV station Nepal Television to produce and air disaster related programs) disaster awareness raising programs have been highly appreciated by the Government of Nepal. Moreover, the major universities of Nepal have been involved in landslide disaster research for the purpose of establishing a research network, and the Government of Nepal has also been invited to jointly develop a disaster management manual for the use of ordinary people to engineers and technicians. This program is expected to develop further.
The main field of investigation was selected to be three major highways in Central Nepal that play the most important role in connecting Nepal and India. These highways pass through the most active trust zone of Nepal and suffer tremendous damage due to landslides and related disasters. So as to understand the mechanism of these failures, first of all hazard mapping of the landslide areas along these highways was done. As a result, a publication in the form of book entitled ‘Landslide Hazard Mapping along Major Highways of Nepal' has been made available. For this publication, the Government of Nepal through the Department of Roads has formally appreciated the efforts of Ehime University and the investigation team in November 2005. All this has highly rated the study results not only from academic but also applicability point of view.
Applicable one-dimensional frozen method for obtaining undisturbed natural sand material containing fine particles

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B).

Project Year :

1999

-

2000

YASHIMA Atsushi, MIMURA Mamoru, ZHANG Feng, OKA Fusao, OKAMURA Mitsu, TANAKA Hiroyuki

　View Summary

Laboratory tests on undisturbed natural sand samples are necessary to assess the liquefaction potential of the sandy ground and to design countermeasures against soil liquefaction. The ground freezing technique has been sometimes used before sand sampling at the field. This technique is, however, well known to be very expensive. On the other hand, the tube sampling technique is much cheaper then the ground freezing technique. The quality of the sample retrieved by the tube sampling technique has been, however, found to be lower than that by the ground freezing technique.
In this study, to improve the quality of the sand sample by the tube sampling technique, the coring tube was redesigned and antifreeze liquid was used to solidify the sand particles and ground water before retrieving the coring tube. The proposed sampling technique was tried at the reclaimed ground in Kishiwada city, Osaka.
Triaxial compression tests on undisturbed samples retrieved by the proposed technique were carried out using large diameter specimens. The experimental results were compared with those obtained from the reconstituted specimens. It is found that the undisturbed specimen has higher stiffness than the reconstituted specimen.
Sand and clay samplings were also conducted at Port Island and Rokko Island to compare the liquefaction potential of both reclaimed islands. Laboratory tests on undisturbed clayey samples were carried out to investigate cyclic strength of clay and consolidation history. PS loggings were also conducted at both islands. Based on laboratory and in situ investigations, the difference in the liquefaction disaster appeared on both islands during the 1995 Hyogoken-Nambu Earthquake was explained.
Anisotropic deformation characteristics of geomaterials in a wide strain range

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Project Year :

1998

-

2000

TAKEMURA Jiro, KODA Masayuki, KUWANO Jiro, KUSAKABE Osamu, MIYAKE Tatsuo, TAKAHASHI Akihiro

　View Summary

Since early 80's there have been a lot of developments for shakers in centrifuge modeling and now many types of shakers with various specification are available in many centrifuges all over the world. However, the shaking directions of these shakers are all horizontal and no shaker which can simulate the; vertical vibration has been developed. In Tokyo Institute of Technology, an attempt has been made to develop 2D shaker, which can make horizontal and vertical motions of shaking table independently in the TIT Mark III Centrifuge.
In order to create the motion with 2 degrees of freedom, at least two actuators are necessary for the shaker. In the newly developed 2D shakers, two inclined servo-hydraulic actuators with horizontal angle of 30 degrees are symmetrically mounted underneath the shaking table. Vertical and horizontal motions can be controlled by putting the same displacements to the cylinders of the two actuators with the same phase and opposite phase respectively. The main difference between normal ID horizontal shaker and 2D H-V shaker is that the shaking table cannot be directly supported by liner way system, which tightly fixed to the reaction frame. The linear way system has two main functions, i.e., supporting the static vertical weight of the shaking table and model under centrifugal acceleration and preventing the rocking motion of the shaking table. In the 2D shaker, the static weight is supported with four air springs so that the force from the actuators underneath the shaking table can entirely act for the dynamic motions. Furthermore two pairs of parallel links were introduced between the shaking table and liner way guides to prevent the rocking motion of the table. The maximum shaking mass is 200 kg and table size are 640x510 mm. Maximum input forces are 35kN and 30kN for the horizontal and vertical directions respectively.
Using the newly developed 2D shaker, preliminary tests were conducted to check its performance. It was confirmed that the horizontal and vertical motions could be independently controlled using the shaker, although there remain many things to improve the performance.
An investigation on interaction between liquefied soil and pile foundation during earthquake

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)

Project Year :

1996

-

1997

TAKEMURA Jiro, KOUDA Masayuki, TAKAHASHI Akihiro

　View Summary

There had been very few records on damages of steel pile type piers. in previous earthquakes. However, several piers located in front of gravity caissons were damaged during the 1995 Hyogoken-Nambu Earthquake. Damage of piles at the site suggested that the lateral flow of the ground might accelerate the failure of the pier. In this study, centrifuge tests were firstly carried out to simulate dynamic behavior and failure of a steel pile type pier damaged in 1995 Hyogoken-Nambu Earthquake. And also some tests with different ground conditions were conducted to discuss the effects of liquefaction of the sand layer under the rubble mound on the lateral flow of the ground and the effect of the approaching plate connecting gravity caisson to ther pier on the dynamic interaction between the two structures.
An investigation on effects of countermeasures against liquefaction of sand deposits with structures

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

Project Year :

1995

-

1996

TAKEMURA Jiro, MATSUDA Takashi, KOUDA Masayuki, OKAMUEA Mitsu

　View Summary

Centrifuge model tests are carried out to study the effect of various countermeasures against liquefaction of sand deposits with an undergrond structure and a structure on surface. Model tests are conduced on five types of models ; one without any countermeasures and four with countermeasures ; sheet pile walls with or without drainage capability, sheet pile walls of which tops are tied with rods and gravel drains.
Following conludsions are drawn from this study.
1.For foundation soil with an underground structure, upward movements of it take place when excess pore pressure beneath the structure reaches a threshold value. In countermeasures to prevent the upward movement, an attempt should be made to keep the excess pore pressure lower than this threshold.
2.Responses of acceleration of structures depend very much on the excess pore pressures generated in foundation soil. The acceleration responses at the very early stages of input motons are similar for all the cases, but the subsequcnt responsese differ for different types of countermeasure. For the cases without drainage, the acceliration of structure decreases with the generation of excess pore pressure. On the other hand, for the cases with drainage, the acceleration of structure increase.
3.Settlements of structures on a ground surface like oil tank and embankment arise from two reasons ; the compression of sand beneath due to consolidation and the other the lateral movement of hte sand. Increase of lateral movement gives rise to an increase in total settlements of the structure, suppression of lateral spreading is necessary.
局部載荷を受ける上部砂層と下部軟弱粘土層から成る二層地盤の圧密特性

日本学術振興会科学研究費助成事業奨励研究(A)

Project Year :

1995

　

　

岡村未対

　View Summary

本研究では、軟弱な正規圧密状態の下部粘土層と、比較的薄い上部粘土層から成る二層地盤の局部載荷時の沈下挙動を調べることを目的とし、遠心模型実験ならびに有限要素解析を行った。実験では、塑性指数が約30の川崎粘土を用いて下部粘土層を、豊浦砂を用いて密な上部砂層を作成し、遠心模型実験装置内で剛な円形基礎に一定の荷重を与え、その間の圧密挙動を調べた。用いた模型基礎の直径Bは実物に換算して5mであり、砂層厚Hを基礎幅Bの1、1.5、2.0倍とした3種類の地盤に対し、載荷重をそれぞれ3種類ずつ変えて実験を行った。また、有限要素法を用いて実験のシュミレートを行った。その結果以下のことが明らかとなった。粘土層表面の鉛直応力は、載荷直後には基礎直下に鉛直応力が集中するが、基礎直下の粘土の沈下速度が大きいことと砂層の剛性が大きいことにより、基礎直下では鉛直応力が時間と共に減少し、周辺領域で応力増加が生じる。この応力分散の結果、基礎の安定性は増し、沈下速度が減少するが、基礎周辺地盤の沈下は大きくなる。また、地盤内の過剰間隙水圧が消散した時点の基礎の最終沈下量は、載荷重強度と共に増加する。また最終沈下量と、載荷重強度と急速載荷条件下での極限支持力の比すなわち荷重比との関係は、砂層厚によらず一本のユニークな曲線となることがわかった。有限要素解析により、実験で観察された粘土層表面での応力の経時変化がうまくとらえることができた。
A fundamental Study on stability of under ground large structures subjecting buoyant forces

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Developmental Scientific Research (B)

Project Year :

1993

-

1994

TAKEMURA Jiro, KITAZUME Masaki, OKAMURA Mitsu, HIROOKA Akihiko

　View Summary

Because of shortage of land space, coastal areas in Japan have been developed and scale of structures become larger and larger in recent years. Large under ground structures in areas of high ground water table might be subjected to large buoyant forces. In this study a series of centrifuge tests were carried out to investigate the influences of depth, size, shape, and flexibility of under ground structures and loading rate on the stability of ground. Stability analyzes are also carried out by using the upper bound method and finite element method. Following conclusions were found ;
(1) The ultimate uplift capacity of structures in sand increases rapidly with increasing in a ratio of depth of cover to width of structures. Calculated ultimate capacity from limit equilibrium method using observed failure mechanism agree well with that measured.
(2) A flexibility of tunnel influences considerably on circumferential stress of tunnel lining ; relatively flexible tunnel could increase its width horizontally, which results in relatively uniform circumferential stress distribution while circumferential stress concentrates on around springline of rigid tunnel.
An Investigation on Horizontal Resistance of Piles and Sheet Piles during Earthquakes.

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for General Scientific Research (A)

Project Year :

1992

-

1993

KIMURA Tsutomu, OKAMURA Mitsu, HIROOKA Akihiko, TAKEMURA Jiro

　View Summary

Dynamic centrifuge tests were carried out using a laminar box in which model pile groups were embedded in a soil layr so as to study the dynamic response of piles and soil mass and their dynamic interaction. We used four different soils (low plasticity soil : Ip=2, Intermediate soil : Ip=10, Clay : Ip=30 and Toyoura Sand) to make soil layrs. A random wave simulating the El Centro record was applied to the soil mass. Comclusions derived from these are as follows.
1) In case of soils with extremely low plasticity, it was observed that the rigidity of ground was reduced during the early stage of earthquakes and as a result, the amplitude of the acceleration of model pile structures was much smaller.
2) The ratio of the observed acceleration spectrum of a model pile structure to the input acceleration spectrum is larger for the higher plasticity soil layr.
3)In case of lower plasticity soil layr, less bending moment was observed in model piles during earthquakes but more permanent displacement was measured.
Dynamic centrifuge model tests with sheet piles were also conducted applying sinusoidal wave as input motion to the model ground. The observed strains in sheet piles were smaller and observed horizontal irrecoverable displacement of sheet piles were larger for the ground with less resistance for liquefaction.
*

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for General Scientific Research (C)

Project Year :

1992

-

1993

TAKEMURA Jiro, OKAMURA Mitsu, HIROOKA Akihiko

　View Summary

Centrifuge model tests were carried out to investigate bearing capacities and deformations of two layred soil in whicha sand oelies a relatively soft clay. Non-dimensional parameters which might directy influence on these phenomena were derived from dimensional analysis. Centrifuge tests were divided into two series. One is bearing capacity tests which were conducted under constant loading rate by using strip and circular footing, and the other is consolidation tests in which model grounds were subjected to a constant load less than its bearing capacity through a circular footing. All test were conducted under 100g and constant thickness of clay laer varying with ratios of the thickness of sand to the footing width, H/B.Following conclusions are derived from this study.
(1) Normalized bearing capacity, 2qf/ gammaB, is found to be a function of H/B, and pO/ gammaB, where gamma is effective unit weight, cu the undrained shear strength f underlying clay, cu/ gamma B normalized bearing capacity of clay and pO/gB normalized overburden resssure. The 2qf/ gammaB increases linearly with cu/ gammaB and pO/ gammaB under constant H/B.
(2) The bearing capacity of the two layred soil increases with H/B until it becomes the bearing capacity of the uniform infinite sand layr. The value of H/B over which the bearing capacity is constant in that of the infinite sand, (H/B)**, is about 1.5 to 2 for circular footing and 4 for strip footing.
(3) Failure mechanisms of the two layred soil can be classified into two categories ; one is general faiure in sand layr which occurred for (H/B)** and the other is punching failure forming a block of sand beneath the footing for H/B smaller than (H/B)**.
(4) Consolidation of the two layred soil under constant load increases with its intensity. A single uique relationship was found between the ratios of applied load intensities to beaing capacities and consolidation settlements in the grounds with H/B of 1.0 to 2.0.

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LPで取得した堤体表面DEMデータ精度に与える植生の影響について

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プレストレスト矢板による堤防液状化対策効果の実験的検証

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加振履歴が液状化強度に及ぼす影響

松木園隆晟, 渡邉翔太, NELSON Fled, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 51st ROMBUNNO.0891 2016

J-GLOBAL
堤体パイピングを模擬した遠心模型実験での表面沈下分布特性

平尾優太郎, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 51st ROMBUNNO.0550 2016

J-GLOBAL
高水作用を受ける均質な砂質土堤防の裏法崩壊メカニズム

笠谷亮太, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 51st ROMBUNNO.0998 2016

J-GLOBAL
Seismic Performance Assessment of River Levees

Takahashi Akihiro, Okamura Mitsu

地盤工学会誌 63 ( 9 ) 6 - 9 2015.09

Rapid communication, short report, research note, etc. (scientific journal)

CiNii J-GLOBAL
Liquefaction Assessment of Thin Saturated Layers in River Levees

Okamura Mitsu

地盤工学会誌 63 ( 9 ) 18 - 21 2015.09

Rapid communication, short report, research note, etc. (scientific journal)

CiNii J-GLOBAL
高速道路基礎地盤への空気注入不飽和化工法適用性検討(その6)事後調査と適用性検討のまとめ

内田純二, 藤井直, 藤原斉郁, 居場博之, 矢部浩史, 橋本欣也, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 70th ROMBUNNO.III-036 2015.08

J-GLOBAL
高速道路盛土基礎地盤への空気注入不飽和化工法適用性検討(その5)―現場実験結果と気液二相流解析の比較―

矢部浩史, 藤原斉郁, 山根信幸, 大石雅彦, 中園康平, 紙田直充, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 70th ROMBUNNO.III-035 2015.08

J-GLOBAL
外水の浸透による微小な堤体表面変位と内部状態の関係に関する実験

伊藤公孝, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 50th ROMBUNNO.541 2015

J-GLOBAL
液状化地盤の変形挙動に関する拡張型相似則の適用性に関する一斉試験

BAI Ke, 飛田哲男, 岡村未対, 竹村次朗, 井合進

地盤工学研究発表会発表講演集(CD-ROM) 50th ROMBUNNO.938 2015

J-GLOBAL
地盤の不飽和化による地中構造物の浮き上がり対策効果

渡邉翔太, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 50th ROMBUNNO.810 2015

J-GLOBAL
空気注入不飽和化工法の高速道路盛土への適用性検討(その6)事後解析

大石雅彦, 藤原斉郁, 居場博之, 矢部浩史, 曽根照人, 内田純二, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 50th ROMBUNNO.546 2015

J-GLOBAL
炭酸カルシウム析出時の飽和度の違いが液状化強度特性に及ぼす影響

小阪佳平, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 50th ROMBUNNO.303 2015

J-GLOBAL
空気注入不飽和化工法の高速道路盛土への適用性検討(その7)事後調査と適用性検討のまとめ

内田純二, 藤井直, 藤原斉郁, 居場博之, 矢部浩史, 橋本欣也, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 50th ROMBUNNO.547 2015

J-GLOBAL
空気注入不飽和化工法の高速道路盛土への適用性検討(その5)空気注入実験の比較

山根信幸, 藤原斉郁, 矢部浩史, 大内正敏, 中園康平, 紙田直充, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 50th ROMBUNNO.545 2015

J-GLOBAL
高速道路盛土基礎地盤への空気注入不飽和化工法の適用性検討(その1)概要

内田純二, 紙田直充, 青木智幸, 山根信幸, 深田久, 大内正敏, 橋本欣也, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 69th ROMBUNNO.III-077 2014.08

J-GLOBAL
高速道路盛土基礎地盤への空気注入不飽和化工法適用性検討(その4)―打込み式注入管による注入実験―

藤原斉郁, 御手洗義夫, 矢部浩史, 藤井直, 中園康平, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 69th ROMBUNNO.III-080 2014.08

J-GLOBAL
高速道路盛土基礎地盤への空気注入不飽和化工法適用性検討(その3)―ダブルパッカー式注入管による注入実験―

矢部浩史, 大石雅彦, 居場博之, 高畑陽, 橋本欣也, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 69th ROMBUNNO.III-079 2014.08

J-GLOBAL
高速道路盛土基礎地盤への空気注入不飽和化工法適用性検討(その2)地盤調査と予備実験計画

藤井直, 小林真貴子, 居場博之, 深田久, 中園康平, 冨田雄一, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 69th ROMBUNNO.III-078 2014.08

J-GLOBAL
2011東北地方太平洋沖地震による霞ケ浦周辺堤防の液状化沈下解析

藤原憲, 陣内尚子, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 69th ROMBUNNO.I-392 2014.08

J-GLOBAL
河川堤防 6.地震に対する評価・対策

岡村未対, 高橋章浩

地盤工学会誌 62 ( 2 ) 34 - 41 2014.02

Rapid communication, short report, research note, etc. (scientific journal)

CiNii J-GLOBAL
Committee Report : The Committee on Education, JSCE

岡村未対, 原隆史

土木学会誌 99 ( 2 ) 58 - 61 2014.02

CiNii
薄い飽和層を有する堤体内液状化判定法

林秀太朗, 井上洋, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 49th ROMBUNNO.494 2014

J-GLOBAL
空気注入不飽和化工法の高速道路盛土への適用性検討(その1)概要

内田純二, 青木智幸, 山根信幸, 深田久, 大内正敏, 橋本欣也, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 49th ROMBUNNO.677 2014

J-GLOBAL
空気注入不飽和化工法の高速道路盛土への適用性検討(その3)本実験計画と準備

居場博之, 高畑陽, 矢部浩史, 大石雅彦, 橋本欣也, 紙田直充, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 49th ROMBUNNO.679 2014

J-GLOBAL
空気注入不飽和化工法の高速道路盛土への適用性検討(その4)本実験結果

藤原斉郁, 冨田雄一, 岡村未対, 御手洗義夫, 矢部浩史, 藤井直, 中園康平

地盤工学研究発表会発表講演集(CD-ROM) 49th ROMBUNNO.680 2014

J-GLOBAL
厚い飽和砂層の液状化発生に及ぼす加振中の排水の影響

川神英彰, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 49th ROMBUNNO.770 2014

J-GLOBAL
空気注入不飽和化工法の高速道路盛土への適用性検討(その2)予備実験

藤井直, 小林真貴子, 居場博之, 深田久, 中園康平, 江川元幾, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 49th ROMBUNNO.678 2014

J-GLOBAL
土中空気の溶解現象による不飽和砂地盤の飽和度経時変化に関する一次元カラム実験

笠谷亮太, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 49th ROMBUNNO.452 2014

J-GLOBAL
空気注入不飽和化工法の注入順序に関する現場実験

藤井直, 居場博之, 深田久, 山浦昌之, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 68th ROMBUNNO.III-080 2013.08

J-GLOBAL
比抵抗変化率による空気注入中の飽和度の推定

居場博之, 山根信幸, 新川直利, 大内正敏, 山田直之, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 68th ROMBUNNO.III-081 2013.08

J-GLOBAL
P波速度検層による不飽和状態の持続性確認

山田直之, 御手洗義夫, 大石雅彦, 深田久, 小泉勝彦, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 68th ROMBUNNO.III-082 2013.08

J-GLOBAL
Development of Liquefaction Countermeasure Technique : Desaturating Soil by Air Injection

山根信幸, 磯谷修二, 藤井直, 山浦昌之, 岡田克寛, 岡村未対

地盤工学会誌 61 ( 1 ) 34 - 35 2013.01

Rapid communication, short report, research note, etc. (scientific journal)

CiNii
空気注入不飽和化工法(Air‐des工法)の開発

山根信幸, 磯谷修二, 藤井直, 山浦昌之, 岡田克寛, 岡村未対

地盤工学会誌 61 ( 1 ) 34-35,1(6) 2013.01

J-GLOBAL
遠心模型実験による鳴瀬川堤防の地震被害の再現と破壊メカニズムの検討

藤原憲, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 48th ROMBUNNO.782 2013

J-GLOBAL
薄い砂層の液状化発生に及ぼす排水の影響

井上洋, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 48th ROMBUNNO.871 2013

J-GLOBAL
道路盛土直下への空気注入による液状化対策効果の実験的検討

冨田雄一, 紙田直充, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 48th ROMBUNNO.578 2013

J-GLOBAL
空気注入不飽和化工法の開発その1(現場実験)

居場博之, 新川直利, 大内正敏, 山田直之, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 48th ROMBUNNO.890 2013

J-GLOBAL
空気注入不飽和化工法の開発その2(事後解析)

大石雅彦, 御手洗義夫, 深田久, 山浦昌之, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 48th ROMBUNNO.892 2013

J-GLOBAL
盛土におけるコーン貫入抵抗比と液状化強度比の関係

林秀太朗, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 48th ROMBUNNO.568 2013

J-GLOBAL
空気注入不飽和化工法における品質管理方法の検討

山根信幸, 磯谷修二, 藤井直, 高野仁, 岡田克寛, 岡村未対, 上田正人

地盤工学研究発表会発表講演集(CD-ROM) 48th ROMBUNNO.891 2013

J-GLOBAL
雨水浸透による盛土内飽和域形成に関する研究

岡本辰也, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 48th ROMBUNNO.534 2013

J-GLOBAL
地盤の不飽和化による液状化対策技術 : 空気注入不飽和化工法(Air-des 工法)の開発

三枝弘幸, 三好朗弘, 藤井直, 山田直之, 岡田克寛, 岡村未対

建設の施工企画 ( 751 ) 25 - 29 2012.09

Article, review, commentary, editorial, etc. (other)

CiNii
防災,安全を確保する社会基盤整備地盤の不飽和化による液状化対策技術空気注入不飽和化工法(Air‐des工法)の開発

三枝弘幸, 三好朗弘, 藤井直, 山田直之, 岡田克寛, 岡村未対

建設の施工企画 ( 751 ) 25 - 29 2012.09

J-GLOBAL
空気注入不飽和化工法の開発その4:空気注入とそのモニタリング

新川直利, 三枝弘幸, 藤井直, 山田直之, 岡田克寛, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 67th ROMBUNNO.III-249 2012.08

J-GLOBAL
空気注入不飽和化工法の開発その6:千葉県袖ケ浦市での現場実験(実験概要)

太田正規, 磯谷修二, 大内正敏, 高野仁, 岡田克寛, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 67th ROMBUNNO.III-251 2012.08

J-GLOBAL
空気注入不飽和化工法の開発その8:設計法の概要

小泉勝彦, 青木宏彦, 磯谷修二, 藤井直, 山浦昌之, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 67th ROMBUNNO.III-253 - 506 2012.08

CiNii J-GLOBAL
道路盛土直下への空気注入による液状化対策効果の実験的検討

冨田雄一, 岡本辰也, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 67th ROMBUNNO.VI-310 - 972 2012.08

CiNii J-GLOBAL
空気注入不飽和化工法の開発その9:レベル2地震動に対する照査の一例

曽根照人, 小泉勝彦, 浅田英幸, 新川直利, 藤井直, 山浦昌之, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 67th ROMBUNNO.III-254 2012.08

J-GLOBAL
地盤の不飽和化が地震時の過剰間隙水圧の発生と地盤の変形に及ぼす影響

岡本辰也, 冨田雄一, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 67th ROMBUNNO.VI-311 2012.08

J-GLOBAL
水平慣性力が硬化則・塑性ポテンシャル曲面に与える影響

田村直登, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 67th ROMBUNNO.III-387 2012.08

J-GLOBAL
空気注入不飽和化工法の開発その1:現地実験(徳島県鳴門市)の概要

岡田克寛, 太田正規, 磯谷修二, 大内正敏, 高野仁, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 67th ROMBUNNO.III-246 2012.08

J-GLOBAL
空気注入不飽和化工法の開発その5:事後調査結果

浅田英幸, 三好朗弘, 藤井直, 山浦昌之, 岡田克寛, 岡村未対, 吉田正

土木学会年次学術講演会講演概要集(CD-ROM) 67th ROMBUNNO.III-250 2012.08

J-GLOBAL
空気注入不飽和化工法の開発その7:千葉県袖ケ浦市での現場実験(品質確認)

三枝弘幸, 三好朗弘, 藤井直, 山田直之, 岡田克寛, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 67th ROMBUNNO.III-252 2012.08

J-GLOBAL
空気注入不飽和化工法の開発その2:注入孔間隔設定実験

藤井直, 三枝弘幸, 三好朗弘, 山田直之, 岡田克寛, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 67th ROMBUNNO.III-247 2012.08

J-GLOBAL
空気注入不飽和化工法の開発その3:注入口配置に関する解析検討

山浦昌之, 藤井直, 浅田英幸, 岡田克寛, 新川直利, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 67th ROMBUNNO.III-248 2012.08

J-GLOBAL
地盤工学会論文賞(和文部門)を受賞して

林和幸, 岡村未対, 安原英明

地盤工学会誌 = / the Japanese Geotechnical Society 60 ( 8 ) 37 - 37 2012.08

CiNii
Innovative Liquefaction Countermeasure Technique : Desaturating Soil by Air Injection

OKAMURA Mitsu

地盤工学会誌 60 ( 5 ) 12 - 15 2012.05

Rapid communication, short report, research note, etc. (scientific journal)

CiNii
道路盛土直下への空気注入による液状化対策効果の実験的検討

冨田雄一, 岡本辰也, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 47th ROMBUNNO.488 2012

J-GLOBAL
空気注入不飽和化工法の現地実証実験その5:千葉県袖ケ浦市での実験概要

太田正規, 磯谷修二, 大内正敏, 高野仁, 岡田克寛, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 47th ROMBUNNO.769 2012

J-GLOBAL
堤体内の飽和領域の厚さが盛土内液状化に及ぼす影響

前田貴史, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 47th ROMBUNNO.679 2012

J-GLOBAL
空気注入不飽和化工法を適用した場合の耐震補強工法

曽根照人, 小泉勝彦, 浅田英幸, 新川直利, 大石雅彦, 山浦昌之, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 47th ROMBUNNO.771 2012

J-GLOBAL
空気注入不飽和化工法開発の現地実証実験その2:注入孔間隔の検討

山浦昌之, 浅田英幸, 新川直利, 藤井直, 岡田克寛, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 47th ROMBUNNO.766 2012

J-GLOBAL
空気注入不飽和化工法の現地実証実験その3:注入空気のモニタリング

新川直利, 三枝弘幸, 藤井直, 山田直之, 岡田克寛, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 47th ROMBUNNO.767 2012

J-GLOBAL
空気注入不飽和化工法の現地実証実験その6:千葉県袖ケ浦市での実験結果

三枝弘幸, 三好朗弘, 藤井直, 山田直之, 岡田克寛, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 47th ROMBUNNO.770 2012

J-GLOBAL
空気注入不飽和化工法の現地実証実験その1:徳島県鳴門市での実験概要

岡田克寛, 青木宏彦, 磯谷修二, 大石雅彦, 高野仁, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 47th ROMBUNNO.765 2012

J-GLOBAL
空気注入不飽和化工法の現地実証実験その4:事後調査

藤井直, 浅田英幸, 三好朗弘, 山浦昌之, 岡田克寛, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 47th ROMBUNNO.768 2012

J-GLOBAL
無線加速度センサによる構造物の多点同時計測と振動の3次元可視化

中畑和之, 高本龍直, 岡村未対, 大賀水田生

土木学会年次学術講演会講演概要集(CD-ROM) 66th ROMBUNNO.CS9-008 2011.08

J-GLOBAL
Liquefaction-induced damage in Christchurch city caused by the 2010 Darfield Earthquake, New Zealand

Kiyota, T, Okamura, M, Toyota, H, Cubrinovski, M, Orense, R. P

Proc. of 8th International Conference on Urban Earthquake Engineering 2011
ダム・堤防(2)(6.地盤と構造物,総括,<特集>第46回地盤工学研究発表会)

岡村未対

地盤工学会誌 59 ( 12 ) 29 - 29 2011

Meeting report

CiNii
地盤の不飽和化が液状化地盤上の盛土の沈下量に及ぼす影響

岡本辰也, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 46th ROMBUNNO.552 2011

J-GLOBAL
塑性のある細粒分を含む不飽和砂質土の液状化強度特性

竹上和希, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 46th ROMBUNNO.197 2011

J-GLOBAL
地震により液状化した鉱さいダムの安定性評価

石川啓考, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 46th ROMBUNNO.531 2011

J-GLOBAL
盛土の剛性に着目した鋼材を用いた液状化対策法に関する研究

森川祐貴, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 46th ROMBUNNO.532 2011

J-GLOBAL
基礎地盤の圧密による盛土の変形が地震時の安定性に及ぼす影響

山本陸登, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 46th ROMBUNNO.530 2011

J-GLOBAL
空気注入によって液状化対策された地盤の未改良部における水圧低下

相原聡, 岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 46th ROMBUNNO.347 2011

CiNii J-GLOBAL
盛土斜面の安定性評価と盛土材料の経年変化に関する研究

塚田匡史, 岡村未対, 安原英明

地盤工学研究発表会発表講演集(CD-ROM) 46th ROMBUNNO.807 2011

J-GLOBAL
地盤の液状化被害に及ぼす余震の影響

岡村未対

地盤工学研究発表会発表講演集(CD-ROM) 46th ROMBUNNO.1008 2011

J-GLOBAL
Reconnaissance Report on the Damage Caused by the 2010 Darfield Earthquake in New Zealand

CUBRINOVSKI Misko

地盤工学会誌 58 ( 12 ) 42 - 43 2010.12

Rapid communication, short report, research note, etc. (scientific journal)

CiNii J-GLOBAL
市民向け親子見学会・講演会・パネル展示

岡村未対

地盤工学会誌 = / the Japanese Geotechnical Society 58 ( 12 ) 14 - 15 2010.12

CiNii
2010年チリMaule地震による被害に対する災害緊急調査団報告

安田進, 小長井一男, 菅野高弘, 岡村未対, 飛田哲男

地盤工学会誌 58 ( 8 ) 42-43,1(6)-1(7) 2010.08

J-GLOBAL
生体触媒を利用した炭酸カルシウム析出砂における透水・物質輸送解析

杉本知弘, 林和幸, 木下尚樹, 安原英明, 岡村未対

地盤工学研究発表会発表講演集 45th ( 1 ) 655 - 656 2010.07

J-GLOBAL
遠心力場における飽和砂地盤への空気注入による地盤不飽和化挙動

五十嵐ひろ子, 岡村未対

地盤工学研究発表会発表講演集 45th ( 1 ) 681 - 682 2010.07

J-GLOBAL
荷重の繰返しを考慮した浅い基礎のマクロエレメントモデル

沖俊貴, 岡村未対

地盤工学研究発表会発表講演集 45th ( 2 ) 1081 - 1082 2010.07

J-GLOBAL
内部応力分布の変化が地震時の盛土の安定性に与える影響

玉邑修二, 岡村未対

地盤工学研究発表会発表講演集 45th ( 2 ) 1463 - 1464 2010.07

CiNii J-GLOBAL
大地震動に対する地盤内不飽和化による液状化抑制効果確認遠心載荷試験

永尾浩一, 明石達生, 末政直晃, 岡村未対, 渦岡良介, 二木幹夫, 服部和徳

地盤工学研究発表会発表講演集 45th ( 1 ) 691 - 692 2010.07

J-GLOBAL
地盤に作用する水平慣性力が基礎の組合せ荷重の支持力に及ぼす影響

田村直登, 岡村未対

地盤工学研究発表会発表講演集 45th ( 2 ) 1089 - 1090 2010.07

J-GLOBAL
生体触媒を活用したカルサイト析出によるゆるい砂の力学特性の改良効果

林和幸, 安原英明, 岡村未対

地盤工学研究発表会発表講演集 45th ( 1 ) 541 - 542 2010.07

J-GLOBAL
既存戸建て住宅地の耐震対策を想定した空気注入工法による液状化免震地盤の可能性

末政直晃, 明石達生, 岡村未対, 渦岡良介, 二木幹夫, 服部和徳, 永尾浩一

地盤工学研究発表会発表講演集 45th ( 1 ) 693 - 694 2010.07

J-GLOBAL
遠心模型実験による土槽壁面の影響範囲に関する研究

石川啓考, 岡村未対

地盤工学研究発表会発表講演集 44th 1363 - 1364 2009.07

J-GLOBAL
炭酸カルシウム結晶の析出が砂の力学特性に及ぼす影響

林和幸, 只信紗也佳, 安原英明, 岡村未対

地盤工学研究発表会発表講演集 44th 579 - 580 2009.07

J-GLOBAL
炭酸カルシウムの結晶析出実験による透水特性の評価

杉本知弘, 林和幸, 木下尚樹, 安原英明, 岡村未対

地盤工学研究発表会発表講演集 44th 781 - 782 2009.07

J-GLOBAL
遠心力場における飽和砂地盤への空気注入実験と気液二相流解析

五十嵐ひろ子, 岡村未対

地盤工学研究発表会発表講演集 44th 951 - 952 2009.07

J-GLOBAL
不飽和化による護岸の液状化対策の遠心模型実験

相原聡, 岡村未対, 井上寿幸

地盤工学研究発表会発表講演集 44th 1423 - 1424 2009.07

J-GLOBAL
部分的に飽和した砂質盛土の動的遠心模型実験

玉邑修二, 岡村未対

地盤工学研究発表会発表講演集 44th 1007 - 1008 2009.07

J-GLOBAL
飽和地盤への空気注入により生じる地盤のゆるみ領域に関する実験的研究

森田薫, 岡村未対, 五十嵐ひろ子

地盤工学研究発表会発表講演集 44th 949 - 950 2009.07

J-GLOBAL
水平加速度が砂地盤の鉛直支持力特性に与える影響

沖俊貴, 岩本一誠, 岡村未対

地盤工学研究発表会発表講演集 44th 1245 - 1246 2009.07

J-GLOBAL
水平加速度が組合せ荷重を受ける砂地盤の支持力に及ぼす影響

岩本一誠, 沖俊貴, 岡村未対

地盤工学研究発表会発表講演集 44th 1247 - 1248 2009.07

J-GLOBAL
ダム・堤防(2)((2)ダム・堤防,6.地盤と構造物,<特集>第44回地盤工学研究発表会)

岡村未対

地盤工学会誌 57 ( 12 ) 27 - 27 2009

CiNii
空気注入による地盤の不飽和化実験

武林昌哉, 藤井直, 西田克司, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 63rd ( Disk 2 ) ROMBUNNO.6-174 2008.08

J-GLOBAL
重力場と遠心力場における飽和砂地盤への空気注入実験

五十嵐ひろ子, 河内義範, 岡村未対, 石丸恭平

土木学会年次学術講演会講演概要集(CD-ROM) 63rd ( Disk 1 ) ROMBUNNO.3-454 2008.08

J-GLOBAL
河川に近接する盛土の地盤の液状化による変位量予測

玉邑修二, 林和幸, 岡村未対, 森春樹, 冨田雄一

土木学会年次学術講演会講演概要集(CD-ROM) 63rd ( Disk 1 ) ROMBUNNO.3-232 2008.08

J-GLOBAL
凍結サンプリング試料への小型コーン貫入抵抗とSPT‐N値の比較

桑田光章, 森重裕亮, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 63rd ( Disk 1 ) ROMBUNNO.3-282 2008.08

J-GLOBAL
土中微生物の代謝を利用した土の力学・透水特性の改良効果に関する基礎実験

林和幸, 安原英明, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 63rd ( Disk 1 ) ROMBUNNO.3-157 2008.08

J-GLOBAL
空気注入による地盤不飽和化の現場実験(その1)全体概要

西田克司, 武林昌哉, 藤井直, 岡村未対

地盤工学研究発表会発表講演集 43rd 1867 - 1868 2008.06

J-GLOBAL
空気注入による地盤不飽和化の現場実験(その2)空気の注入

藤井直, 西田克司, 武林昌哉, 岡村未対, 小松満, 森川佳太

地盤工学研究発表会発表講演集 43rd 1869 - 1870 2008.06

J-GLOBAL
組合せ荷重を受ける帯基礎のマクロエレメントモデル

古川直樹, 岡村未対

地盤工学研究発表会発表講演集 43rd 1341 - 1342 2008.06

J-GLOBAL
空気注入による地盤不飽和化の現場実験(その3)比抵抗トモグラフィによる不飽和領域の計測

神宮司元治, 今里武彦, 岡村未対, 武林昌哉, 西田克司, 藤井直

地盤工学研究発表会発表講演集 43rd 1871 - 1872 2008.06

J-GLOBAL
微生物代謝を利用した地盤改良工法に関する基礎的検討

林和幸, 安原英明, 岡村未対

地盤工学研究発表会発表講演集 43rd 965 - 966 2008.06

J-GLOBAL
空気注入による地盤不飽和化の現場実験(その4)気液二相流解析によるシミュレーション

河内義範, 安原英明, 岡村未対

地盤工学研究発表会発表講演集 43rd 1873 - 1874 2008.06

J-GLOBAL
非塑性不飽和シルトの液状化強度特性に及ぼす空気の圧縮性とサクションの影響

野口康平, 岡村未対

地盤工学研究発表会発表講演集 43rd 451 - 452 2008.06

J-GLOBAL
構造物を有する不飽和履歴を受けた砂地盤の遠心模型振動実験

五十嵐玲奈, 井澤淳, 竹村次朗, 増田雅士, 岡村未対

地盤工学研究発表会発表講演集 43rd 1863 - 1864 2008.06

J-GLOBAL
山岳道路盛土擁壁の支持力破壊に対する簡易な耐震点検法の検討

重松慎哉, 岡村未対

地盤工学研究発表会発表講演集 43rd 1925 - 1926 2008.06

J-GLOBAL
空気注入による地盤不飽和化の遠心模型実験

竹村次朗, 五十嵐玲奈, 関栄, 岡村未対

地盤工学研究発表会発表講演集 43rd 1865 - 1866 2008.06

J-GLOBAL
砂斜面上帯基礎の動的支持力の実験的研究

菅田伯忠, 岡村未対, 二神治, 芳ノ内信也

地盤工学研究発表会発表講演集 43rd 1353 - 1354 2008.06

J-GLOBAL
動的性質(1)((2)動的性質,3.地盤材料-砂質土,<特集>第43回地盤工学研究発表会)

岡村未対

地盤工学会誌 56 ( 12 ) 26 - 26 2008

CiNii
高知県の3地点における地盤液状化強度特性

森重裕亮, 岡村未対, 河内義範, 野田巌

土木学会年次学術講演会講演概要集(CD-ROM) 62nd ( Disk 1 ) ROMBUNNO.3-302 2007.09

J-GLOBAL
2006年ジョグジャ地震における地震被害と地盤特性の関係

片山雅夫, 森伸一郎, 岡村未対

地盤工学研究発表会発表講演集 42nd 1925 - 1926 2007.06

J-GLOBAL
斜面上帯基礎の支持力・変形特性と地震時変位量予測法の開発

菅野靖幸, 岡村未対, 古川直樹

地盤工学研究発表会発表講演集 42nd 1353 - 1354 2007.06

J-GLOBAL
不飽和履歴を受けた砂地盤の遠心模型液状化実験

五十嵐玲奈, 関栄, 井澤淳, 竹村次朗, 増田雅士, 岡村未対

地盤工学研究発表会発表講演集 42nd 1877 - 1878 2007.06

J-GLOBAL
気液二相流解析による空気注入時の地盤飽和度変化予測

森藤隆元, 安原英明, 岡村未対, 河内義範

地盤工学研究発表会発表講演集 42nd 1079 - 1080 2007.06

J-GLOBAL
液状化対策としての空気注入による地盤不飽和化に関する基礎的実験

細川晃一, 増田雅士, 岡村未対, 五十嵐怜奈, 竹村次朗

地盤工学研究発表会発表講演集 42nd 1879 - 1880 2007.06

J-GLOBAL
State of Geo-hazard Mitigation in Shikoku Region against the Nankai Earthquake

矢田部龍一, 長谷川修一, 岡村未対, BHANDARY Netra

土と基礎 55 ( 5 ) 11 - 13 2007.05

J-GLOBAL
構造物の耐久性向上と性能評価方法に関する研究

萩原良二, 大下武志, 石原雅規, 中島伸一郎, 田村敬一, 杉田秀樹, 岡村未対, 高橋章浩, 小林寛, 谷本俊輔, 運上茂樹, 星隈順一, 西田秀明, 塩島亮彦, 吉田武, 伊藤正秀, 久保和幸, 藪雅行, 坂本康文, 寺田剛, 谷口聡, 真下英人, 砂金伸治, 日下敦, 福井次郎, 村越潤, 麓興一郎, 長屋優子, 稲垣由紀子, 中谷昌一, 白戸真大, 野々村佳哲

土木研究所報告 ( 207 ) 53 - 107 2007.04

CiNii J-GLOBAL
南海地震に対する四国地域の地盤防災の現状

矢田部龍一, 岡村未対, 長谷川修一

土木学会四国支部南海地震研究 3 46 - 58 2007
空気注入によるシルト地盤の不飽和化

岡村未対, ELGAMAL Ahmed

土木学会年次学術講演会講演概要集(CD-ROM) 61st ( Disk 1 ) ROMBUNNO.3-120 2006.09

J-GLOBAL
組み合わせ荷重を受ける砂地盤上の帯基礎の荷重―変位モデル

古川直樹, 岡村未対, 二神治, 和田俊彦

地盤工学研究発表会発表講演集 41st 1359 - 1360 2006.06

J-GLOBAL
サンプリング試料の動的特性について

河内義範, 岡村未対, 藤原身江子

地盤工学研究発表会発表講演集 41st 415 - 416 2006.06

J-GLOBAL
Geotechnical Special Publication: Preface

Akio Abe, Tarek Abdoun, Abbas Abghari, Scott A. Ashford, Victoria Bennett, Scott J. Brandenberg, Jonathon D. Bray, Dongdong Chang, Misko Cubrinovski, Stephen E. Dickenson, Ricardo Dobry, Ahmed Elgamal, Travis M. Gerber, Unit Gulerce, David Ha, Stuart K. Haigh, Ching Lung Hung, Susumu Iai, Jun Izawa, Jonathan Knappett, Kohji Koyamada, Steve L. Kramer, Bruce L. Kutter, I. P. Lam, San Shyan Lin, S. P.Gopal Madabhushi, Geoff Martin, Claudia Medina, Shinichiro Mori, Yoshi Moriwaki, Mitsu Okamura, Kyle M. Rollins, Masayoshi Sato, Tom Shantz, Hiroko Suzuki, Akihiro Takahashi, Jiro Takemura, Shuji Tamura, Tetsuo Tobita, Javier Ubilla, Akihiko Uchida, Ryosuke Uzuoka, Dan W. Wilson, Mourad Zeghal, Jin Xing Zha, Ross W. Boulanger, Kohji Tokimatsu

Geotechnical Special Publication 2006.01
地盤災害に関する国際シンポジウム(カザフスタン)開催報告

岡村未対

土と基礎 = Soil mechanics and foundation engineering 53 ( 8 ) 35 - 35 2005.08

CiNii
組合せ荷重を受ける斜面上帯基礎の支持力実験的研究

菅野靖幸, 岡村未対, 二神治, 堀政理

地盤工学研究発表会発表講演集 40th 1491 - 1492 2005.06

J-GLOBAL
組合せ荷重を受ける砂地盤の支持力・変形特性

堀政理, 岡村未対, 菅野泰幸

地盤工学研究発表会発表講演集 40th 1471 - 1472 2005.06

J-GLOBAL
不飽和土の液状化強度に及ぼす空気圧縮性の影響

曽我恭匡, 岡村未対, 矢田部龍一

地盤工学研究発表会発表講演集 40th 511 - 512 2005.06

J-GLOBAL
崩壊土砂の衝突に対する待受け式擁壁の変位推定手法の検討

内田太郎, 曽我部匡敏, 小山内信智, 岡村未対, 吉田望

砂防学会研究発表会概要集 2005 372 - 373 2005.05

J-GLOBAL
A SIMPLE METHOD FOR EVALUATING SEISMIC FAILURE POTENTIAL OF RETAINING WALLS ON SLOPES

OKAMURA Mitsu

Proceedings of the JSCE Earthquake Engineering Symposium 28 ( 0 ) 3 - 3 2005

　View Summary

In the design practice of retaining walls for road embankment, in particular for stacked block type retaining walls which have been widely used in Japan, any eartuquake effects have not been taken into account. However, the heavy damages to mountain roads caused by Niigataken-chuetsu EQ clearly indicated nessesity to secure aseismisity of such retaining walls. In this study, the failure mechanism was studied through invesitigation of the damaged and undamaged walls. A simple method to evaluate failure potential of existing retaining walls, in which cone penetration test and bearing capacity calculation are incorpotated, are proposed.

DOI CiNii
SCP改良地盤の飽和度の調査

岡村未対, 石原雅規, 田村敬一

地盤工学研究発表会発表講演集 39th 1001 - 1002 2004.06

DOI J-GLOBAL
A STUDY ON PRACTICAL DESIGN METHOD OF PILE FOUNDATION IN LIQUEFIED FOUNDATION SOIL CONSIDERING GROUND DEFORMATION

田村敬一, 岡村未対, 三上卓, 谷本俊輔

土木研究所重点プロジェクト研究報告書平成15年度 357 - 365 2004

J-GLOBAL
IMPROVEMENT OF SEISMIC REMEDIATION TECHNIQUE FOR RIVER DIKE FOUNDED ON LIQUEFIABLE SOIL

田村敬一, 岡村未対, 石原雅規, 谷本俊輔

土木研究所重点プロジェクト研究報告書平成15年度 16 - 22 2004

J-GLOBAL
Effects of unsaturated sand overlying liquefied sand on pile foundation during strong base shaking (Part 2, Centrifuge tests)

Hayashi Kazuyuki, Tamura Keiichi, Okamura Mitu, Tanimoto Shunsuke, Inoue Yumiko

Proceedings of the Japan National Conference on Geotechnical Engineering 39 ( 0 ) 1575 - 1576 2004

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液状化地盤における杭基礎の損傷には、表層の非液状化層の影響が大きいことが指摘されている。これは、液状化地盤の変形に伴って不飽和層の地盤も変形し、大きな土圧が杭に作用するためと考えられる。そこで、地震時に液状化層の上にある表層不飽和層が杭基礎に与える影響を確認する実験を遠心力載荷試験装置を用いて行った。地盤は支持層、液状化層および不飽和層の3層からなる互層地盤とし、層厚を変えて3ケース作成し、地盤内には杭頭部に上部工を付けた杭模型を設置した。その結果、不飽和層厚が大きいほど杭に与える土圧が大きくなることが確認できた。

DOI CiNii J-GLOBAL
Effects of unsaturated sand overlying liquefied sand on a pile foundation during strong base shaking (Part 3, Analysis of piles on Winkler-spring connected to horizontally displaced ground)

Tanimoto Shunsuke, Tamura Keiichi, Okamura Mitu, Hayashi Kazuyuki, Inoue Yumiko

Proceedings of the Japan National Conference on Geotechnical Engineering 39 ( 0 ) 1577 - 1578 2004

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現行の道路橋示方書では液状化地盤中の橋脚杭基礎の設計に地盤変形の影響は考慮されておらず、杭に発生する応力が必ずしも適切に評価されていない可能性がある。そこで本研究では、液状化地盤中における橋梁の橋脚杭基礎の設計に、地盤変形の影響を考慮できる簡易な設計法として考えられる、静的な応答変位法の適用性の検証を行った。特に表層の非液状化層が杭に生じる応力に及ぼす影響に着目し、別報(その2)で行った実験を対象として応答変位法による計算を行った。地盤バネ定数は、別報(その1)の結果を用いた。適切な地盤変位および上部工慣性力を与えることで計算結果と実験結果はよい対応を示すことが分かった。

DOI CiNii J-GLOBAL
Liquefaction resistance of desaturated sand improved with SCP

Ishihara Masanori, Okamura Mitsu, Tamura Keiichi

Proceedings of the Japan National Conference on Geotechnical Engineering 39 ( 0 ) 1003 - 1004 2004

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サンドコンパクションパイルの施工においては、砂を地盤中に押出すために高圧空気を用いる。このため、少なくとも施工直後には、改良地盤の飽和度が最大70%程度まで低下することがわかっている。本研究では、施工直後の改良地盤から採取した凍結試料を用いて非排水繰返しせん断中空ねじり試験を行い、現地盤の不飽和状態における液状化強度を求めた。本試験結果と近傍の試料を用いて実施した完全飽和状態の三軸試験および中空ねじり試験結果とを比較したところ、液状化強度が増加していることが確認できた。しかし、N値の高い地盤ほど、不飽和による液状化強度の増加の割合は小さかった。

DOI CiNii J-GLOBAL
Effect of unsaturated sand overlying liquefied sand on a pile foundation during strong base shaking (Part 1, Coefficient of subgrade reaction unsaturated sand)

Inoue Yumiko, Tamura Keiichi, Okamura Mitu, Tanimoto Shunsuke, Hayashi Kazuyuki

Proceedings of the Japan National Conference on Geotechnical Engineering 39 ( 0 ) 1573 - 1574 2004

　View Summary

液状化地盤における杭基礎の損傷には、表層の非液状化層の影響が大きいことが指摘されている。これは、液状化地盤の変形に伴って不飽和層の地盤も変形し、大きな土圧が杭に作用するためと考えられる。本研究では下層が飽和層、上層が不飽和層の2層地盤を作成し、杭基礎に作用する不飽和層の土圧を測定する遠心力模型実験を行い、土圧と地盤加速度を2階積分して算出した地盤変位の関係から地盤反力係数を求めた。地盤反力係数に影響する要因について検討し、不飽和層の地盤バネを深さ、相対密度、相対変位の関数として定式化した。

DOI CiNii J-GLOBAL
地盤の流動が杭基礎に及ぼす影響に関する実験的研究(速報)

田村敬一, 岡村未対, 谷本俊輔

土木学会年次学術講演会講演概要集(CD-ROM) 58th ( Disk 1 ) I-328 2003.09

J-GLOBAL
盛土法尻の液状化対策工に作用する地震時土圧(その1 土圧漸増成分)

岡村未対, 石原雅規, 田村敬一

土木学会年次学術講演会講演概要集(CD-ROM) 58th ( Disk 1 ) III-128 2003.09

J-GLOBAL
液状化地盤中の杭基礎に作用する地盤変形の影響に関する遠心力模型実験(その3 群杭基礎に作用する土圧)

尾山康弘, 田村敬一, 岡村未対, 谷本俊輔, 小野和行

土木学会年次学術講演会講演概要集(CD-ROM) 58th ( Disk 1 ) III-141 2003.09

J-GLOBAL
盛土法尻の液状化対策工に作用する地震時土圧(その3 締固め工法への適用)

石原雅規, 岡村未対, 大下武志

土木学会年次学術講演会講演概要集(CD-ROM) 58th ( Disk 1 ) III-130 2003.09

J-GLOBAL
盛土法尻の液状化対策工に作用する地震時土圧(その2 土圧振動成分)

谷本俊輔, 岡村未対, 石原雅規, 田村敬一

土木学会年次学術講演会講演概要集(CD-ROM) 58th ( Disk 1 ) III-129 2003.09

J-GLOBAL
液状化地盤中の杭基礎に作用する地盤変形の影響に関する遠心力模型実験(その4 杭加速度に比例する土圧評価法の提案)

小野和行, 田村敬一, 岡村未対, 谷本俊輔, 尾山康弘

土木学会年次学術講演会講演概要集(CD-ROM) 58th ( Disk 1 ) III-142 2003.09

J-GLOBAL
護岸背後の液状化により杭基礎に作用する流動圧に関する振動台実験

谷本俊輔, 田村敬一, 岡村未対

地震工学研究発表会梗概集 27 ( 0 ) 182 - 182 2003

DOI CiNii
Centrifuge Model Tests on Effects of Liquefied Soil Deformation on Pile Foundations-Part1, Behavior of Liquefied Soil and Earth Pressure Acting on a Pile

Tanimoto Shunsuke, Tamura Keiichi, Okamura Mitu, Ono Kazuyuki

Proceedings of the Japan National Conference on Geotechnical Engineering 38 ( 0 ) 1949 - 1950 2003

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1995年1月の兵庫県南部地震では、液状化地盤中の杭基礎の被害として、杭頭付近のみならず液状化層内部でも被害が報告されている。この液状化層内部での被害は、液状化した地盤の変形に伴う土圧の影響であることが種々の研究で報告されている。この現象を定量的に評価するためには、杭基礎および液状化地盤の運動と杭基礎に作用する土圧の関係を明らかにする必要がある。そこで本研究では、液状化地盤および杭基礎を模擬した遠心力模型実験を行った。その結果より、地盤の相対密度と透水係数による液状化地盤の挙動の違い、および杭基礎に作用する土圧の違いについて検討を行った。

DOI CiNii J-GLOBAL
Deformation characteristics of saturated silty sand after liquefaction

Ishihara Masanori, Okamura Mitsu, Oshita Takeshi

Proceedings of the Japan National Conference on Geotechnical Engineering 38 ( 0 ) 485 - 486 2003

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豊浦砂および豊浦砂に非塑性シルト分(DLクレイ)を10%、20%、また塑性シルト分(藤森粘土)を10%混入した3種類の合成砂を用いて、非排水中空ねじり試験を行った。その結果、液状化強度は、非塑性シルト分10%、豊浦砂、非塑性シルト分20%、塑性シルト分10%の順となった。非塑性シルト分10%の場合には、豊浦砂の間隙にシルト粒子がつまり不のダイレイタンシーの発生が抑制される効果が、シルト分により砂粒子が分散する負の効果を上回ったために高くなったものと考えられる。しかし、液状化後の剛性回復傾向に関して言えば、豊浦砂、非塑性シルト10%、非塑性シルト20%、塑性シルト10%の順に小さくなり、砂粒子同士の接点がシルト粒子との接点に置き換わることで低下するものと推察された。

DOI CiNii J-GLOBAL
Study on Seismic Design of Retaining Walls based on Residual Displacement during Earthquakes

Kondoh Masuo, Tamura Keiichi, Okamura Mitsu

Proceedings of the Japan National Conference on Geotechnical Engineering 38 ( 0 ) 1619 - 1620 2003

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擁壁の耐震設計は、静的照査法により求めた安全率が許容安全率を満足するような断面設定で行っている。しかし、国際的基準や我が国の他の設計基準においては、仕様規程から性能規程への移行が進められているところである。本報告では、性能規程に基づく耐震設計法の1つの考え方として、根入れ効果を考慮した擁壁の変位推定法により算出した地震時残留変位量と許容残留変位量とを照査する手法を紹介する。さらに、現行設計法により設計した擁壁と本手法により設計した擁壁の断面比較や今後の課題について紹介するものである。

DOI CiNii J-GLOBAL
Centrifuge Model Tests on Effects of Liquefied Soil Deformation on Pile Foundations-Part2,Evaluation of Earth Pressure Acting on a Pile-

Ono Kazuyuki, Tamura Keiichi, Okamura Mitu, Tanimoto Shunsuke

Proceedings of the Japan National Conference on Geotechnical Engineering 38 ( 0 ) 1951 - 1952 2003

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液状化地盤中の杭基礎の被害は、上部構造物の慣性力以外に、液状化した地盤の変形により発生する土圧の影響に関連付けられると考えられている。そのため、液状化に伴う地盤変形の影響に関する研究は種々行われているが、その影響のメカニズムについては未解明な点が多く残されている。そこで本研究では、液状化地盤中の杭基礎を模擬し、地盤変形に着目した遠心力模型実験を行い、杭基礎に作用する土圧の発生メカニズムと、地盤と杭基礎との間に生じる相対運動、すなわち相対速度および相対変位、さらに杭加速度との関係について検討を行った。その結果、杭基礎に作用する土圧は、杭加速度に依存するものと、さらに相対速度および相対変位に依存するものとに区分できることを明らかにし、その評価を行った。

DOI CiNii J-GLOBAL
Degree of saturation of sand improved with SCP 27 years ago

Okamura Mitsu, Ishihara Masanori, Tamura Keiichi

Proceedings of the Japan National Conference on Geotechnical Engineering 38 ( 0 ) 2027 - 2028 2003

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SCPで改良された地盤の飽和度はおよそ90%以下とかなり小さく、締固の効果だけでなく飽和度が低下したことによる液状化強度の増加が期待される。しかしながら、施工直後に地盤中に含まれる空気量が長期的に低下し、飽和度が増加してゆくことも考えられる。そこで、約20年前にSCPで液状化対策を行った地盤から、凍結サンプリング法により試料を採取し、飽和度を調べた。その結果、飽和度はおよそ90%程度であり、永久ではないにしろかなりの程度長期にわたって地盤中の空気が存続することがわかった。

DOI CiNii J-GLOBAL
重力式擁壁の地震時変位量擁壁の根入れ深さを考慮した地震時変位計算法の検証

斎藤由紀子, 岡村未対, 田村敬一

土木学会年次学術講演会講演概要集(CD-ROM) 57th III-536 2002.09

J-GLOBAL
地盤の非線形性を考慮した基礎の回転変位の評価方法に関する研究

田村敬一, 岡村未対, 小林寛

土木学会年次学術講演会講演概要集(CD-ROM) 57th I-204 2002.09

J-GLOBAL
盛土法尻部締固め改良地盤の地震時変形量簡易予測法

石原雅規, 岡村未対

土木学会年次学術講演会講演概要集(CD-ROM) 57th III-560 2002.09

J-GLOBAL
重力式擁壁の地震時変位量基礎地盤の支持力特性

岡村未対, 斉藤由紀子, 田村敬一, 坪川洋友

土木学会年次学術講演会講演概要集(CD-ROM) 57th III-535 2002.09

J-GLOBAL
Liquefaction resistance profile of sand deposit improved with non-vibratory sand compaction piles

Okamura Mitsu, Ishihara Masanori

Proceedings of the Japan National Conference on Geotechnical Engineering 37 ( 0 ) 1103 - 1104 2002

DOI CiNii J-GLOBAL
Simple model of shear properties for liquefied sand

Ishihara Masanori, Okamura Mitsu

Proceedings of the Japan National Conference on Geotechnical Engineering 37 ( 0 ) 2051 - 2052 2002

DOI CiNii J-GLOBAL
重力式擁壁の地震時変位予測法の開発

斉藤由紀子, 岡村未対, 松尾修

日本道路会議論文集 24th 76 - 77 2001.10

J-GLOBAL
重力式擁壁の地震挙動とその予測法について擁壁の水平・鉛直・回転変位予測法

岡村未対, 松尾修

土木学会年次学術講演会講演概要集第3部 56th ( A ) 246 - 247 2001.09

J-GLOBAL
盛土構造物の耐震対策効果に関する遠心模型実験のシミュレーション

高野令男, 岡村未対, 松尾修

土木学会年次学術講演会講演概要集第3部 56th ( B ) 672 - 673 2001.09

J-GLOBAL
重力式擁壁の地震時挙動とその予測法について擁壁の滑動・沈下・回転を考慮した地震時変位計算法の検証

斉藤由紀子, 松尾修, 岡村未対, 中村伸也

土木学会年次学術講演会講演概要集第3部 56th ( A ) 244 - 245 2001.09

J-GLOBAL
地盤の液状化による盛土沈下対策工(締固め工法)の効果

岡村未対, 田本修一, 松尾修

地盤工学研究発表会発表講演集 36th 1343 - 1344 2001.05

J-GLOBAL
液状化性地盤上の鋼矢板二重仮締切の動的遠心模型実験

岡村未対, 松尾修

地盤工学研究発表会発表講演集 36th 1349 - 1350 2001.05

CiNii J-GLOBAL
弾塑性FEMの結果に及ぼす入力パラメータのバラツキの影響と結果の信頼性

高野令男, 岡村未対, 松尾修

地震工学研究発表会講演論文集 26 ( 26 ) 1213 - 1216 2001

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近年、動的有限要素解析法が実務にも取り入れられてきた。このような解析法を実務設計に用いる場合、結果の信頼性評価を行って適切な安全率あるいは部分係数を決める必要がある。結果の信頼性に影響を及ぼす要因として、解析手法自体の不確実さ、入力パラメータ (土質定数等) の不確実さが上げられる。そこで本研究では、動的有限要素解析コード (LIQCA) を用い、液状化地盤上の盛土の地震時変形解析を行い、入力パラメータのバラツキが沈下量に及ぼす影響を調べ為また、解析結果に対して信頼性の評価を試みた。

DOI CiNii
Simulation of centrifugal and dynamic model experiment of banking by effective stress analysis method.

岡村未対, 松尾修

土木学会年次学術講演会講演概要集第3部 54th ( A ) 312 - 313 1999.08

J-GLOBAL
Centrifuge modeling of embankments resting on liquefiable subsoil.

岡村未対, 田本修一, 松尾修

地盤工学研究発表会発表講演集 34th 2089 - 2090 1999.06

J-GLOBAL
Horizontal loading test of footing on low strength soil-cement columns in centrifuge

Kuwano, J, Okamura, M, Yasumoto, K

Proc. 13th Southeast Asian Geotechnical Conf. 807 - 810 1998
A study on p-y curves of pile in a sandy slope.

岡本道孝, 神田政幸, 岡村未対, 竹村次朗

土木学会年次学術講演会講演概要集第3部 52nd ( B ) 50 - 51 1997.09

J-GLOBAL
Centrifuge tests of lateral bearing capacity of single piles in unconsolidated cohesive soil.

NGUYEN T N, 安元健二, 岡村未対, 日下部治

地盤工学研究発表会発表講演集 32nd ( 2-2 ) 1593 - 1594 1997.05

J-GLOBAL
Centrifuge modelling on test embankment on soft clay with sheet pile.

石井裕泰, 小沢一喜, 岡村未対, 竹村次朗, 日下部治

地盤工学研究発表会発表講演集 32nd ( 2-2 ) 1313 - 1314 1997.05

J-GLOBAL
Stability of landing pier with steel piles subjected to lateral flow of ground caused by liquefaction during earthquake.

川口喜孝, 岡村未対, 高橋章浩, 竹村次朗

地盤工学研究発表会発表講演集 32nd ( 2-1 ) 935 - 936 1997.05

J-GLOBAL
Microscopic observation of particle behavior in shear zone of densed sand.

米今智信, 高橋章浩, 岡村未対, 日下部治

地盤工学研究発表会発表講演集 32nd ( 2-1 ) 483 - 484 1997.05

J-GLOBAL
Effects of embedment length and ground condition on performance of soft clay with sheet pile subject to fill loading.

石井裕泰, 岡村未対, 竹村次朗, 日下部治

地盤工学研究発表会発表講演集 32nd ( 2-2 ) 1311 - 1312 1997.05

J-GLOBAL
Prediction of load-settlement behavior of circular footings on compressive sandy soil.

佐原史浩, 岡村未対, 日下部治

地盤工学研究発表会発表講演集 32nd ( 2-2 ) 1403 - 1404 1997.05

J-GLOBAL
Effects of Initial Void Ratio and Stress History on Mechanical Characteristics of Low Plastic Intermediate Soils.

岡村未対, 竹村次朗, 桑野二郎, LU Y D

地盤工学研究発表会発表講演集 32nd ( 2-1 ) 471 - 472 1997.05

J-GLOBAL
Centrifuge Model Tests of Embankment on Soft Clay with Sheet Pile Wall Reinforcement against Settlement of Adjacent Ground.

竹村次朗, 石井裕泰, 岡村未対, 高橋章浩, 日下部治

東京工業大学土木工学科研究報告 ( 55 ) 61 - 78 1997.03

J-GLOBAL
Horizontal bearing force characteristic of foundation based on cement improved ground of low strength column.

安元健二, 佐原史浩, 岡村未対, 桑野二郎

土木学会年次学術講演会講演概要集第3部 51st ( B ) 574 - 575 1996.09

J-GLOBAL
The effect of sheet pile construction as a settlement countermeasure for the soft clay ground subjected to embankment loading.

石井裕泰, 岡村未対, 木村孟, 竹村次朗

土木学会年次学術講演会講演概要集第3部 51st ( A ) 476 - 477 1996.09

J-GLOBAL
An experimental study on the bearing capacities of footings on sand under eccentric loading.

岡村未対, 三原淳慎, 竹村次朗, 桑野二郎

地盤工学研究発表会発表講演集 31st ( 2-2 ) 1569 - 1570 1996.05

J-GLOBAL
Centrifuge model tests on vertical cuts with sheet pile wall in overconsolidated clay.

SOU S, 秋畑純一, 岡村未対, 竹村次朗, 木村孟

地盤工学研究発表会発表講演集 31st ( 2-2 ) 1831 - 1832 1996.05

J-GLOBAL
Effects of Consolidation Stress on Drained Shear Characteristics of Low Plastic Soils.

久田成昭, 桑野二郎, 竹村次朗, 岡村未対, RIKU U

地盤工学研究発表会発表講演集 31st ( 2-1 ) 873 - 874 1996.05

J-GLOBAL
Evaluation of bearing capacities of footing on sand subjected eccentric load.

三原淳慎, 岡村未対, 竹村次朗, 桑野二郎, 木村孟

地盤工学研究発表会発表講演集 31st ( 2-2 ) 1581 - 1582 1996.05

J-GLOBAL
Lateral loading tests of a single pile in sand using geotechnical centrifuge.

金縄知樹, 神田政幸, 岡村未対, 竹村次朗, 桑野二郎

地盤工学研究発表会発表講演集 31st ( 2-2 ) 1757 - 1758 1996.05

J-GLOBAL
An Experimental Study on p-y Curves of Piles in Sand.

金縄知樹, 岡村未対, 神田政幸, 竹村次朗, 桑野二郎

地盤工学研究発表会発表講演集 31st ( 2-2 ) 1755 - 1756 1996.05

J-GLOBAL
軟弱地盤における土留め掘削時の安定性に及ぼす根入れの影響

秋畑純一, 曹志浜, 岡村未対, 竹村次朗

土木学会年次学術講演会講演概要集第3部 50th ( B ) 994 - 995 1995.09

J-GLOBAL
Stability on vertical excavations with sheet pile wall in soft clay.

安部勝也, SOU S, 岡村未対, 竹村次朗, 木村孟

土質工学研究発表会発表講演集 30th ( 3-3 ) 1633 - 1636 1995.05

J-GLOBAL
Centrifuge model tests on excavation in a stacked drift tunnel in saturated soils.

清藤幹雄, 野城一栄, 岡村未対, 桑野二郎, 尾上篤生

土質工学研究発表会発表講演集 30th ( 3-3 ) 1967 - 1968 1995.05

J-GLOBAL
Deformation of intermediate soils during loading.

渡部要一, 桑野二郎, 岡村未対, 竹村次朗

土質工学研究発表会発表講演集 30th ( 3-2 ) 1267 - 1268 1995.05

J-GLOBAL
A study on settlement of clay layer which is applied cyclic loading.

石井裕泰, 三原淳慎, 岡村未対, 桑野二郎, 竹村次朗

土質工学研究発表会発表講演集 30th ( 3-2 ) 1311 - 1312 1995.05

J-GLOBAL
Effects of shape of footings on bearing capacitites of sand.

杢谷真一, 岡村未対, 竹村次朗, 木村孟

土質工学研究発表会発表講演集 30th ( 3-2 ) 1337 - 1340 1995.05

J-GLOBAL
場所打ち杭の先端支持力に与える応力履歴の影響評価に関する室内試験

奥村文直, 岡村未対, 竹村次朗

東京工業大学土木工学科研究報告 ( 49 ) p34 - 45 1994.06

CiNii
Loading rate effects on bearing capacities and deformations of intermidiate soils.

PARK J, 岡村未対, 竹村次朗, 木村孟

土質工学研究発表会発表講演集 29th ( 3-2 ) 1377 - 1380 1994.05

J-GLOBAL
A study on bearing capacities and deformations of sand reinforced with geogrid, overlying weak sand.

三原淳慎, 岡村未対, 竹村次朗

土質工学研究発表会発表講演集 29th ( 3-2 ) 1375 - 1376 1994.05

J-GLOBAL
Consolidation of Two Layered Soil under Circular Loading.

川崎将生, 三原淳慎, 岡村未対, 竹村次朗, 木村孟

土質工学研究発表会発表講演集 29th ( 3-2 ) 1341 - 1344 1994.05

J-GLOBAL
On the Behavior of Stacked-drift type Tunnels during Core Excavation.

酒井貴之, 岡村未対, 竹村次朗, 木村孟, 尾上篤生

土質工学研究発表会発表講演集 29th ( 3-3 ) 1983 - 1986 1994.05

J-GLOBAL
Stability of underground structure in sand subjected to uplift force.

野城一栄, 塩梅崇, 岡村未対, 竹村次朗, 木村孟

土質工学研究発表会発表講演集 29th ( 3-3 ) 2009 - 2010 1994.05

J-GLOBAL
Effects of repeated loading on bearing capacities and settlement of piles.

杢谷信一, 岡村未対, 竹村次朗, 奥村文直

土質工学研究発表会発表講演集 29th ( 3-2 ) 1495 - 1498 1994.05

J-GLOBAL
繰り返し載荷を受ける砂地盤中の杭の支持力・変形特性

川崎将生, 岡村未対, 竹村次朗, 奥村文直

土木学会年次学術講演会講演概要集第3部 48th 776 - 777 1993.09

J-GLOBAL
A study on bearing capacity of circular footings on sand overlying clay.

岡村未対, 川崎将生, 竹村次朗, 木村孟, 末政直晃

土質工学研究発表会発表講演集 28th ( 2-2 ) 1595 - 1596 1993.05

J-GLOBAL
砂地盤の支持力変形特性に関する研究

岡村未対

東京工業大学学位論文 1993

CiNii
Bearing capacity of sand layer overlying clay.

川崎将生, 岡村未対, 竹村次朗, 木村孟

土質工学研究発表会発表講演集 27th ( 2-2 ) 1449 - 1452 1992.05

J-GLOBAL
A failure mechanism of sand layers reinforced with geogrid due to strip loading.

岡村未対, 末政直晃, 竹村次朗, 木村孟

土質工学研究発表会発表講演集 27th ( 2-2 ) 2215 - 2218 1992.05

J-GLOBAL
Bearing characteristics of a sand layer lying between soft clay layers.

岡村未対, 竹村次朗, 神田政幸, 木村孟

土木学会年次学術講演会講演概要集第3部 46th 922 - 923 1991.09

J-GLOBAL
An investigation on the bearing capacity of sand layers reinforced with geogrid.

岡村未対, 末政直晃, 竹村次朗, 木村孟

土質工学研究発表会発表講演集 26th ( 2-2 ) 1987 - 1990 1991.06

J-GLOBAL
Bearing capacities of a sand layer sandwiched by clay.

神田政幸, 岡村未対, 末政直晃, 木村孟

土質工学研究発表会発表講演集 26th ( 2-2 ) 1267 - 1268 1991.06

J-GLOBAL
Bearing capacities and deformations of low plastic soils.

PARK J, 岡村未対, 木村孟, 竹村次朗

土質工学研究発表会発表講演集 26th ( 2-2 ) 1269 - 1270 1991.06

J-GLOBAL
Influence of strain velocity on shear property of low plasticity cohesive soil.

中薗裕, 岡村未対, 竹村次朗, 中瀬明男

土木学会年次学術講演会講演概要集第3部 45th 206 - 207 1990.09

J-GLOBAL
A study of bearing capacities and deformations for sand overlying clay ground.

岡村未対, 竹村次朗, 木村孟

土質工学研究発表会発表講演集 25th ( 2-2 ) 1281 - 1284 1990.05

J-GLOBAL
Failure mechanism and bearing capacities of sand under a cylindrical footing.

岡村未対, 木村孟, 斉藤邦夫, 竹村次朗

土質工学研究発表会発表講演集 23rd ( 2-2 ) 1293 - 1294 1988.05

CiNii J-GLOBAL

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Industrial Property Rights

地盤の飽和度測定方法及び飽和度測定装置

酒井運雄, 岡村未対, 湯川浩則, 中島敬祐, 立川日出男, 立川智勝

Patent

J-GLOBAL
地盤試料のサンプリング方法及びサンプリング装置

酒井運雄, 岡村未対, 湯川浩則, 奥澤泰造, 立川日出男, 立川智勝

Patent

J-GLOBAL
地盤の飽和度簡易測定方法

特許第5882159号

吉田正, 乾一幸, 小松洋之, 伊藤直志, 岡村未対

Patent

J-GLOBAL
地盤の飽和度の測定方法

特許第5559660号

岡村未対, 三枝弘幸, 三好朗弘, 藤井直, 山田直之

Patent

J-GLOBAL
地盤の飽和度測定方法

吉田正, 乾一幸, 小松洋之, 伊藤直志, 岡村未対

Patent

J-GLOBAL
地盤の飽和度の測定方法

岡村未対, 三枝弘幸, 三好朗弘, 藤井直, 山田直之

Patent

J-GLOBAL
表示システム、表示装置、及び中継装置

甲展明, 加藤陽平, 大鹿豊重, 岡村竜也, 上野和真

Patent

J-GLOBAL
空気注入による地盤の飽和度の計測方法

特許第4899164号

神宮司元治, 岡村未対, 西垣誠, 武林昌哉, 武藤雅俊, 藤井直, 今里武彦

Patent

J-GLOBAL
空気注入による地盤の飽和度の計測方法

神宮司元治, 岡村未対, 西垣誠, 武林昌哉, 武藤雅俊, 藤井直, 今里武彦

Patent

J-GLOBAL

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Syllabus

Seminar on Environment & Disaster Prevention

School of Creative Science and Engineering

2025 fall semester
Civil and Environmental Engineering Laboratory

School of Creative Science and Engineering

2025 spring semester
Civil and Environmental Engineering B

School of Creative Science and Engineering

2025 fall semester
Geotechnical Engineering

School of Creative Science and Engineering

2025 spring semester
Exercise B of Environmental Conservation & Disaster Prevention

School of Creative Science and Engineering

2025 fall semester
Exercise A of Environmental Conservation & Disaster Prevention [S Grade]

School of Creative Science and Engineering

2025 spring semester
Soil Mechanics [S Grade]

School of Creative Science and Engineering

2025 fall semester
Soil Mechanics

School of Creative Science and Engineering

2025 fall semester
Exercise B of Environmental Conservation & Disaster Prevention [S Grade]

School of Creative Science and Engineering

2025 fall semester
Seminar on Environment & Disaster Prevention [S Grade]

School of Creative Science and Engineering

2025 fall semester
Geotechnical Structure Design and Maintenance

School of Creative Science and Engineering

2025 fall semester
Earthquake Geotechnical Engineering

School of Creative Science and Engineering

2025 spring semester
Exercise A of Environmental Conservation & Disaster Prevention

School of Creative Science and Engineering

2025 spring semester
Soil Mechanics:Exercises

School of Creative Science and Engineering

2025 full year
Graduation Thesis or Project [S Grade]

School of Creative Science and Engineering

2025 full year
Civil and Environmental Laboratory

School of Creative Science and Engineering

2025 spring semester
Graduation Thesis or Project

School of Creative Science and Engineering

2025 full year
Civil and Environmental Laboratory [S Grade]

School of Creative Science and Engineering

2025 spring semester
Civil & Environmental Engineering Fresh Seminar

School of Creative Science and Engineering

2025 spring semester
Laboratory Work on Soil Mechanics [S Grade]

School of Creative Science and Engineering

2025 fall semester
Laboratory Work on Soil Mechanics

School of Creative Science and Engineering

2025 fall semester
Soil Mechanics B

School of Creative Science and Engineering

2025 fall semester
Soil Mechanics B [S Grade]

School of Creative Science and Engineering

2025 fall semester
Graduation Thesis or Project Spring [S Grade]

School of Creative Science and Engineering

2025 spring semester
Soil Mechanics [S Grade]

School of Creative Science and Engineering

2025 fall semester
Graduation Thesis or Project Fall [S Grade]

School of Creative Science and Engineering

2025 fall semester
Graduation Thesis or Project Fall

School of Creative Science and Engineering

2025 fall semester
Graduation Thesis or Project Spring

School of Creative Science and Engineering

2025 spring semester
Laboratory Work on Soil Mechanics [S Grade]

School of Creative Science and Engineering

2025 fall semester
Laboratory Work on Soil Mechanics

School of Creative Science and Engineering

2025 fall semester
Geotechnical Engineering [S Grade]

School of Creative Science and Engineering

2025 spring semester
Geotechnical Engineering

School of Creative Science and Engineering

2025 spring semester
Introduction to Civil and Environmental Engineering [S Grade]

School of Creative Science and Engineering

2025 fall semester
Introduction to Civil and Environmental Engineering

School of Creative Science and Engineering

2025 fall semester
Laboratory Work on Civil and Environmental Engineering [S Grade]

School of Creative Science and Engineering

2025 spring semester
Laboratory Work on Civil and Environmental Engineering

School of Creative Science and Engineering

2025 spring semester
Soil Mechanics

School of Creative Science and Engineering

2025 fall semester
Master's Thesis (Department of Civil and Environmental Engineering)

Graduate School of Creative Science and Engineering

2025 full year
Master's Thesis (Department of Civil and Environmental Engineering)

Graduate School of Creative Science and Engineering

2025 full year
Research on Soil Mechanics

Graduate School of Creative Science and Engineering

2025 full year
Seminar on Soil Mechanics D

Graduate School of Creative Science and Engineering

2025 fall semester
Seminar on Soil Mechanics C

Graduate School of Creative Science and Engineering

2025 spring semester
Seminar on Soil Mechanics B

Graduate School of Creative Science and Engineering

2025 fall semester
Seminar on Soil Mechanics A

Graduate School of Creative Science and Engineering

2025 spring semester
Advanced Soil Mechanics B

Graduate School of Creative Science and Engineering

2025 fall semester
Seminar on Soil Mechanics A

Graduate School of Creative Science and Engineering

2025 spring semester
Seminar on Soil Mechanics D

Graduate School of Creative Science and Engineering

2025 fall semester
Seminar on Soil Mechanics C

Graduate School of Creative Science and Engineering

2025 spring semester
Seminar on Soil Mechanics B

Graduate School of Creative Science and Engineering

2025 fall semester
Advanced Soil Mechanics A

Graduate School of Creative Science and Engineering

2025 spring semester
Advanced Soil Mechanics B

Graduate School of Creative Science and Engineering

2025 fall semester
Advanced Soil Mechanics A

Graduate School of Creative Science and Engineering

2025 spring semester
Research on Soil Mechanics

Graduate School of Creative Science and Engineering

2025 full year
Exercise B of Civil & Environmental Engineering

Graduate School of Creative Science and Engineering

2025 fall semester
Exercise A of Civil & Environmental Engineering

Graduate School of Creative Science and Engineering

2025 spring semester
Research on Soil Mechanics

Graduate School of Creative Science and Engineering

2025 full year

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Sub-affiliation

Faculty of Science and Engineering Graduate School of Creative Science and Engineering

Research Institute

2025

-

2026

Waseda Research Institute for Science and Engineering Concurrent Researcher