Updated on 2025/06/25

写真a

 
OKAMURA, Mitsu
 
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
メールアドレス

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

    <p>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.</p>

    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

    &nbsp;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.<br>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. <br>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.<br>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&#039;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

    &nbsp;&nbsp;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

    &nbsp;&nbsp;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

  • 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 (Sr). 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 Sr of 99.3% for sand with considerable amount of fines. A technique of high accuracy measurement of Sr 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.<br>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 Nd-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 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%. 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)
  • 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 K&ouml;tter's equations in which the stress dependency and anisotropy of the internal friction angle &phi;&prime; 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 &phi;&prime;.

    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

▼display all

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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Misc

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    陣内尚子, 岡村未対

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    今村衛, 岡村未対, 小野耕平

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    小野耕平, 岡村未対

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    小野耕平, 窪内将吾, 岡村未対

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    井上直大, 岡村未対, 小野耕平

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    今村衛, 岡村未対, 小野耕平

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    LEE K.‐T, 宗行正則, 上山高史, 長谷川剛基, 丸岡雄一郎, 岡村未対

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    東呂木喬, 田村元希, 岡村未対, 小野耕平

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    藤井直, 山田直之, 山根信幸, 矢部浩史, 小泉勝彦, 岡村未対

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    渡邉翔太, 岡村未対

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    田村元希, 岡村未対

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    陣内尚子, 岡村未対, 高木翔平

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    小阪佳平, 岡村未対

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  • 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

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    松木園隆晟, 渡邉翔太, NELSON Fled, 岡村未対

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  • Seismic Performance Assessment of River Levees

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  • 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

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    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

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    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

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    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

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    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

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    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

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    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

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    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

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    岡村 未対

    地盤工学会誌   59 ( 12 ) 29 - 29  2011

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    CiNii

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    CiNii J-GLOBAL

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    CUBRINOVSKI Misko

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    CiNii J-GLOBAL

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    CiNii

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    安田進, 小長井一男, 菅野高弘, 岡村未対, 飛田哲男

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    地盤工学研究発表会発表講演集   45th ( 1 ) 655 - 656  2010.07

    J-GLOBAL

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    地盤工学研究発表会発表講演集   45th ( 1 ) 681 - 682  2010.07

    J-GLOBAL

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    地盤工学研究発表会発表講演集   45th ( 2 ) 1081 - 1082  2010.07

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    地盤工学研究発表会発表講演集   45th ( 2 ) 1463 - 1464  2010.07

    CiNii J-GLOBAL

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    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

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    地盤工学研究発表会発表講演集   45th ( 2 ) 1089 - 1090  2010.07

    J-GLOBAL

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    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

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    地盤工学研究発表会発表講演集   45th ( 1 ) 693 - 694  2010.07

    J-GLOBAL

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    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

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    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

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    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

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    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

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    地盤工学研究発表会発表講演集   44th   1423 - 1424  2009.07

    J-GLOBAL

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    地盤工学研究発表会発表講演集   44th   1007 - 1008  2009.07

    J-GLOBAL

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    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

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    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

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    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

  • 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

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    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

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    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

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    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

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    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

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    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

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    地盤工学研究発表会発表講演集   43rd   1869 - 1870  2008.06

    J-GLOBAL

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    地盤工学研究発表会発表講演集   43rd   1341 - 1342  2008.06

    J-GLOBAL

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    地盤工学研究発表会発表講演集   43rd   1871 - 1872  2008.06

    J-GLOBAL

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    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

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    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

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    地盤工学研究発表会発表講演集   43rd   451 - 452  2008.06

    J-GLOBAL

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    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

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    地盤工学研究発表会発表講演集   43rd   1925 - 1926  2008.06

    J-GLOBAL

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    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

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    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

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    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

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    地盤工学研究発表会発表講演集   42nd   1925 - 1926  2007.06

    J-GLOBAL

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    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

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    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

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    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

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    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

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    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

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    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

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    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

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    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

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    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

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    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

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    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

     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。

    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

     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。

    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

     View Summary

    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

     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。

    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

     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。

    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

     View Summary

    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

     View Summary

    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

     View Summary

    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

     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。

    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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  • Faculty of Science and Engineering   Graduate School of Creative Science and Engineering

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    Waseda Research Institute for Science and Engineering   Concurrent Researcher