Updated on 2022/11/26

写真a

 
AKAKI, Hirokazu
 
Scopus Paper Info  
Paper Count: 0  Citation Count: 0  h-index: 2

Citation count denotes the number of citations in papers published for a particular year.

Affiliation
Faculty of Science and Engineering, School of Creative Science and Engineering
Job title
Professor

Concurrent Post

  • Affiliated organization   Global Education Center

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

Research Institute

  • 2020
    -
    2022

    理工学術院総合研究所   兼任研究員

Education

  •  
    -
    1978

    Waseda University   Faculty of Science and Engineering   Department of Civil Engineering  

Degree

  • 早稲田大学   工学博士

  • Doctor of Engineering

Research Experience

  • 1994
    -
     

    Waseda University, Professor

  • 1986
    -
    1994

    Waseda University, Associate Professor

  • 1986
    -
    1994

    Waseda University, Associate Professor

  • 1984
    -
    1986

    Waseda University, Assistant Professor

  • 1982
    -
    1984

    Waseda University, Research Associate

Professional Memberships

  •  
     
     

    British Geotechnical Association

  •  
     
     

    建築学会

  •  
     
     

    地盤工学会

  •  
     
     

    土木学会

 

Research Areas

  • Geotechnical engineering

Research Interests

  • Soil Mechanics, Environmental Geotechnics

Papers

  • 地盤工学における性能設計の基礎と実装

    赤木 寛一

    地盤工学会誌   vo.67 ( No.10 ) 52 - 59  2019.10

  • Study of infrared thermal application for detecting defects within tunnellining

    Hirokazu Akagia

    Tunnelling and Underground Space Technology   No.86   186 - 197  2019.01

  • Amazing underground construction technology in Japan

    Hirokazu Akagi

    Geotechnical Aspects of Underground Construction In Soft Graound/Taylor & Francis     3 - 19  2018.01

  • Ground Improvement by the Freezing Method for Underground Space Utilization

    Alireza Afshani, Hirokazu Akagi

    Geo-Chicago 2016: Sustainable Geoenvironmental Systems   ( 271 ) 778 - 786  2016  [Refereed]

     View Summary

    In underground spaces under high water pressure, the need to seal the periphery and face of the working environment and establish a stable front is a challenging issue. One method of creating a stable working front and sealing it against underground water pressure is ground freezing. In this study, application of a freezing method for underground space utilization is investigated. A case study related to part of a comprehensive underground expansion project in a Tokyo suburb is considered. Construction includes a junction of a main tunnel with a rampway that connects the underground tunnel route to the ground surface. At this construction site, the segment connecting the main route and rampway needs to be widened. Because of this enlargement and sequence of tasks below the water table, a temporary stable working front and hydraulically waterproof zone are necessary. As an effective method of ground improvement, freezing is used. Ground behavior around the underground expanded periphery and on the greenfield level due to freezing and thawing action is predicted, and a parametric study of the effect of the surrounding soil stiffness on the freezing behavior is conducted. Additionally, the closing time between freezing pipes is also predicted.

  • WIDE RANGE ATTENUATION PROPERTIES OF GROUND VIBRATION PROPAGATED FROM CUT-AND-COVER TUNNEL

    PROCEEDINGS OF TUNNEL ENGINEERING, JSCE   70 ( 3 ) I_83 - I_91  2015

     View Summary

    Attenuation properties of subway-induced ground vibration propagated from cut-and-cover tunnels were experimentally investigated to improve the accuracy of empirical prediction methods for the Vibration Level and ground-borne noise level in buildings. Vibration accelerations both in the tunnels and on the ground were measured in and around the Tokyo area. This paper presents distributed levels of measured acceleration in the tunnels and ground. Dependency of attenuation properties on frequency is examined, and internal damping in every 1/3 octave band are calculated based on the Bornitz formula. Damping factors with ground conditions are also discussed.

    CiNii

  • 特殊ポリマー安定液を用いた場所打ち杭の施工例 AWARD-Sapli(アワードサプリ)工法

    浅野均, 赤木寛一, 近藤義正, 上原精治, 請川誠, 下坂賢二

    基礎工   vol.42 ( No.3 ) 46 - 49  2014.03

  • Erratum : EVALUATION OF LONG TERM STABILITY OF CHEMICALLY STABILIZED SAND WITH GROUTING [Journal of Japan Society of Civil Engineers, Ser. C (Geosphere Engineering) Vol. 69 (2013) , No. 2 pp. 162-173]

    Doboku Gakkai Ronbunshuu C   70 ( 1 ) 53 - 53  2014

     View Summary

    There were the following typos in the article, "Journal of Japan Society of Civil Engineers, Ser. C (Geosphere Engineering) Vol. 69 (2013) , No. 2 pp. 162-173"

    CiNii

  • 気泡を利用した掘削工法

    赤木寛一

    土木技術   vol.69 ( No.1 ) 29 - 34  2014.01

  • Stress-path and piezometric head field analysis of soil during earth pressure balanced shield tunneling

    A. Afshani, H. Akagi

    GEOTECHNICAL ASPECTS OF UNDERGROUND CONSTRUCTION IN SOFT GROUND     295 - 302  2014  [Refereed]

     View Summary

    The effects of earth pressure balanced (EPB) tunneling on the soil stress path and piezometric head of the soil during tunnel advancement are considered in this study. First, the 3D stress distributions of the area near the crown and spring line of the tunnel are investigated, after which the tunnel stress path with respect to the Mohr-Coulomb yielding surface is presented. Next, by taking into account the three significant factors of a) advance rate of the tunnel face, b) consolidation coefficient of the soil, and c) overburden depth of the tunnel, a parametric study is conducted and the effect of EPB tunneling on the piezometric head field of the soil is examined.

  • Advancement simulation of parallel and their interchange with two other subway lines usinga a new FEM approach, a case study

    Alireza Afshani, Hiroshi Dobashi, Kazuhito Komiya, Hirokazu Akagi

    Geotechnics for Sustainable Development - Geotec Hanoi 2013, Phung (edt). Construction Publisher.    2013.11

  • 地盤沈下に起因するシールドトンネルの 長期変形挙動に関する解析的検討

    焼田 真司, 仲山 貴司, 津野 究, 高橋 博樹, 小宮 一仁, 赤木 寛一

    土木学会論文集C(地圏工学)   Vol. 69, ( No. 4 ) 457 - 468  2013.05

     View Summary

    In order to predict the long-term deformation of shield tunnels located in soft clayey ground and conduct their long-term management, this paper investigates the calculation method of long term tunnel deformation due to the consolidation settlement of surrounding ground. Although it is required to take into account of the non-linear behavior caused by the generation of cracks within the tunnel lining and their enlargement, it is difficult to employ the sophisticated segment-ring model for tunnel lining because of calculation time and memory. Therefore, this paper proposes the empirical modeling method of the reduction of stiffness due to the generation and the enlargement of cracks and combines it with the soil-water-coupling analysis of tunnel deformation. The proposed method was verified and validated by the comparison between the calculation results and the field measurement results.

    CiNii

  • Destructuration of soft clay during Shield TBM tunnelling and its consequences

    Hirokazu Akagi

    Deutsche Bodenmechanik Tagung 2013    2013.05

  • 地盤沈下に起因するシールドトンネルの 長期変形挙動に関する解析的検討

    焼田 真司, 仲山 貴司, 津野 究, 高橋 博樹, 小宮 一仁, 赤木 寛一

    土木学会論文集C(地圏工学)   Vol. 69, ( No. 4 ) 457 - 468  2013.05

     View Summary

    In order to predict the long-term deformation of shield tunnels located in soft clayey ground and conduct their long-term management, this paper investigates the calculation method of long term tunnel deformation due to the consolidation settlement of surrounding ground. Although it is required to take into account of the non-linear behavior caused by the generation of cracks within the tunnel lining and their enlargement, it is difficult to employ the sophisticated segment-ring model for tunnel lining because of calculation time and memory. Therefore, this paper proposes the empirical modeling method of the reduction of stiffness due to the generation and the enlargement of cracks and combines it with the soil-water-coupling analysis of tunnel deformation. The proposed method was verified and validated by the comparison between the calculation results and the field measurement results.

  • 薬液注入工法で固化した改良体の 耐久性評価に関する研究

    仲山 貴司, 澤田 亮, 平岡 陽, 赤木 寛一

    土木学会論文集C(地圏工学)   Vol. 69 ( No. 2, ) 162 - 173  2013.05

     View Summary

    Chemical grouting method can be used in order to improve the loose sand against the earthquake induced liquefaction. Long term stability of chemically stabilized sand is required for the chemical grouting method to be used to prevent the earthquake induced liquefaction. However, it is quite difficult to obtain and predict the long term performance of chemically stabilized sand.<br> Experimental investigation of long term stability of chemically stabilized sand has been carried out by using the promotion of the silica diffusion and leaching within the chemically stabilized sand under the water flow. It is demonstrated that the time dependent variation of the physical properties of chemical stabilized sand is closely related to the silica movement and leaching from the chemically stabilized sand. Silica movement and leaching of the chemically stabilized sand are obtained by the finite element analysis based on the silica diffusion equation.<br> It is concluded that the long term stability of chemically stabilized sand can be quantitatively evaluated using the combination of the flow water promotion test of chemically stabilized sand and the finite element analysis based on the silica diffusion equation.

    DOI CiNii

  • SHIELD TUNNELING ADVANCEMENT SIMULATION USING 3D FEM CONSIDERING DISTANCE FACTOR AND ITS VALIDATION

    Alireza Afshani, Hiroshi Dobashi, Shinji Konishi, Kazuhito Komiya, Hirokazu Akagi, Kaho Orihara

       2013.04

  • SHIELD TUNNELING ADVANCEMENT SIMULATION USING 3D FEM CONSIDERING DISTANCE FACTOR AND ITS VALIDATION

    Alireza Afshani, Hiroshi Dobashi, Shinji Konishi, Kazuhito Komiya, Hirokazu Akagi, Kaho Orihara

    2013 Geotechnical Society of Singapore (GeoSS).     431 - 437  2013.04

  • 等価骨格間隙比に基づく薬液固結砂の力学特性評価の試み

    兵動 太一, 赤木 寛一

    地盤工学ジャーナル   Vol.8,No.1   109 - 118  2013.03

  • Approach to Numerical Simulation of Shield Tunneling and Its Evaluation by Comparison with Field Data

    A. Afshani, H. Dobashi, S. Konishi, K. Komiya, H. Akagi

    TU-Seoul 2013    2013.03

  • その他(1.一般,総括,<特集>第47回地盤工学会研究発表会)

    赤木 寛一

    地盤工学会誌   60 ( 12 ) 13 - 13  2012.12

    CiNii

  • A STUDY ON NUMERICAL SIMULATION DURING CHEMICAL GROUTING

    Takashi Nakayama, Naoki Tachibana, Noriyuki Okano, Hirokazu Akagi

    ADVANCES IN GROUND TECHNOLOGY AND GEO-INFORMATION     351 - 361  2012  [Refereed]

     View Summary

    The chemical grouting has the advantages that equipments are small and the direction of boring has flexibility. Therefore, in Japan, it is frequently used for a soil-improvement method in the railway construction site where workspace or working hours is limited. However, it has the possibility to cause a ground displacement around the site. Because there is no method that estimates it quantitatively, the design based on old cases is still used mainly and focuses on safety overly.
    In this Study, the simplified numerical analysis for ground behavior due to the osmotic pressure during injection is proposed.

    DOI

  • Chemical Grouting Method

      59 ( 3 ) 42 - 43  2011.03

    CiNii

  • Current Underground Construction Technology in Tokyo

    HIROKAZU AKAGI

    Korean Geotechnical Society     44 - 49  2011.03

  • 薬液注入工法

    赤木 寛一

    地盤工学会誌   Vol.59 No.3 ( 638 ) 44 - 49  2011.03

  • NUMERICAL STUDY ON CRACK PROPAGATION IN SEGMENT OF SHIELD TUNNEL

    PROCEEDINGS OF TUNNEL ENGINEERING, JSCE   67 ( 3 ) I_109 - I_116  2011

     View Summary

    Long-term consolidation of surrounding ground may cause deformation, cracks of segment, opening of joints and other faults in shield tunnels located in soft clayey soil. To distinguish the cracks and opening caused by consolidation from those caused by another reason, such as construction method, it is required to develop the calculation method considering the progress of cracks and opening in accordance with the time-history stress and strain experienced by the shield tunnels. This paper proposes the calculation method, coupling the ground-tunnel interaction analysis and the sophisticated tunnel deformation analysis.

    DOI CiNii

  • 水素ガスの地中での移動特性とその検知

    岡本 英樹, 五味 保城, 赤木 寛一

    土木学会論文集F   Vol.66 No.1 ( 1 ) 146 - 157  2010.03

     View Summary

    A hydrogen gas is expected to be a clean, environmentally-friendly future energy source. In order to supply a hydrogen gas with a fuel cell station, the employment of buried pipeline is being studied in Japan and foreign countries. To implement this idea, the most important thing is to ensure the safety against the hydrogen gas leakage from the buried pipeline. Specifically, the understanding of a hydrogen gas movement charactersitics within the compacted soil is extremely important as well as the reliability assessment of pipeline materials. Aiming to establish a safety basis for buried hydrogen gas pipeline system, the full-scale experiment on underground hydrogen gas leakage and the numerical simulation were carried out. The movement characteristics of a hydrogen gas within the soil was investigated and the leaked hydrogen gas was detected at the road surface by the portable gas detector, following the procedure specified by the legal requirement.

    DOI CiNii

  • 水素ガスの地中での移動特性とその検知

    岡本 英樹, 五味 保城, 赤木 寛一

    土木学会論文集F   Vol.66 No.1 ( 1 ) 146 - 157  2010.03

     View Summary

    A hydrogen gas is expected to be a clean, environmentally-friendly future energy source. In order to supply a hydrogen gas with a fuel cell station, the employment of buried pipeline is being studied in Japan and foreign countries. To implement this idea, the most important thing is to ensure the safety against the hydrogen gas leakage from the buried pipeline. Specifically, the understanding of a hydrogen gas movement charactersitics within the compacted soil is extremely important as well as the reliability assessment of pipeline materials. Aiming to establish a safety basis for buried hydrogen gas pipeline system, the full-scale experiment on underground hydrogen gas leakage and the numerical simulation were carried out. The movement characteristics of a hydrogen gas within the soil was investigated and the leaked hydrogen gas was detected at the road surface by the portable gas detector, following the procedure specified by the legal requirement.

  • LONG TERM FIELD MONITORING OF CHEMICALLY STABILIZED SAND WITH GROUTING

    Hirokazu Akagi, Kazuhito Komiya, Mitsuhiro Shibazaki

    GROUND IMPROVEMENT TECHNOLOGIES AND CASE HISTORIES     383 - 387  2010  [Refereed]

     View Summary

    Chemical grouting method is employed frequently within on urban area to improve the strength and permeability characteristics of soft ground. In order to ensure the long term performance of chemically stabilized sand with grouting, the systematic field measurement of the mechanical characteristics of the chemical grouted sandy soil has been carried out by the Japanese Grouting Association for the period of five years, from 2000 to 2005. The test field soil condition consisted mainly of comparatively dense sand with gravel and the ground water table was around 6 m below the ground surface. Four types of silicate grouting materials were employed. Standard penetration tests (SPT), lateral loading tests (LLT), in-situ permeability tests and flow meter tests within a bored hole were conducted to obtain the strength and permeability characteristics of the grouted sand. The SPT-N value and LLT deformation modulus of the grouted sand with a silicate material of an organic hardener has increased for the initial two years and then decreased for the next year. However, its N-value was still the triple times the initial one. It has been concluded that silicate grouted materials have demonstrated the satisfactory performance during the period of three years.

    DOI

    Scopus

    3
    Citation
    (Scopus)
  • Finite Element Simulation of Construction Processes of A Mechanized HEP &amp; JES Tunnelling Method

    Hiroki Takahashi, Kazuhito Komiya, Hirokazu Akagi, Takashi Nakayama, Yu Ohashi

    EURO:TUN 2009 2nd International Conference on Computational Methods in Tunnelling/Aedificatio Publishers     31 - 36  2009.09

  • Variation of The Relief of External Nodal Force for 2D-FE Analysis Associated with Shield Tunnelling Processes

    Ai Fujinuma, Hiroki Takahashi, Kazuhito Komiya, Hirokazu Akagi, Takaaki Nishimura

    EURO:TUN 2009 2nd International Conference on Computational Methods in Tunnelling/Aedificatio Publishers     99 - 106  2009.09

  • Utilization of Tunnels and Underground Space in Tokyos

    Hirokazu Akagi

    ABMS     269 - 274  2008.08

  • 掘削土砂に気泡と水を添加した地盤掘削用安定液の開発と適用

    近藤義正, 仲山貴司, 赤木寛一

    土木学会論文集C   vol.64 ( No.3 ) 505 - 518  2008.07

  • シールド工事に伴う地盤変状計測

    小宮一仁, 赤木寛一

    基礎工   vol.36 ( No.6 ) 47 - 51  2008.06

  • 魅力ある国際会議をめざして-第3回日中地盤工学シンポジウム(重慶)-

    赤木寛一

    地盤工学会誌   vol.5 ( No.6 ) 34  2008.06

  • 注入工法による地盤改良の長期利用の現状と課題

    赤木寛一

    基礎工   vol.5 ( No.5 ) 34  2008.05

  • Subsidence prediction of compacted subgrade soil (Kanto loam soil) using cyclic traffic loading experiments

    H. Minagata, K. Yoshizaki, N. Hagiwara, H. Akagi

    DEFORMATION CHARACTERISTICS OF GEOMATERIALS, VOLS 1 AND 2   vol.1   327 - +  2008  [Refereed]

     View Summary

    During road excavations for laying gas distribution pipelines, the reuse of the excavated soil for the subgrade backfill significantly reduces the environmental impact. However, when Kanto loam soil, which is a local soil that is widely distributed in the Kanto region, Japan, is employed for the backfill material, the relationship between the amount of the subsidence of the subgrade soil and the cyclic traffic loading must be investigated. In this study, cyclic loading tests on compacted Kanto loam soils are conducted to investigate the subsidence characteristics by using a confined compression apparatus. The subsidence prediction method for subgrade soil (Kanto loam soil) under cyclic traffic loading is proposed on the basis of the cyclic loading test results. Full-scale traffic loading experiments are performed on roadbeds backfilled with Kanto loam soil. Consequently, good correlation is obtained between the amount of the predicted subsidence and the measurement results.

  • Trial Asset Management System for Underground Infrastructure in Japan

    Hirokazu Akagi, Shuzo Hayashi, Masayuki Shiga

    Proceedings of the International symposium on Tunnelling for Urban Development     61 - 66  2007.12

  • 気泡安定液の開発と適用

    近藤義正, 赤木寛一

    基礎工   vol.36 ( No.1 ) 62 - 65  2007.12

  • Flocculation and dehydration control during soil washing process using soil plasticity index and pH

    Hirokazu Akagi, Mitsuo Mouri

    NEW FRONTIERS IN CHINESE AND JAPANESE GEOTECHNIQUES     30 - +  2007  [Refereed]

     View Summary

    Soil washing is physical-chemical separation for removing the portion of the soil that is most polluted mainly by screen, hydrocyclone, and flotation. This reduces the amount of soil needing further cleanup. In most cases, the contaminants, such as fuels and heavy metals, reside and concentrated in fine-grained soils. The overflow from the hydrocyclone, consisting of fines and water, is treated and converted to a 45%-55% dry solids sludge cake by flocculants addition, sedimentation, thickening, and dewatering. This sludge cake contains the target contaminants and therefore must be managed by disposal at a properly permitted off-site disposal facility. The fines treatment is very important for the recovery of water and for making the sludge cake as dry as possible, in order to create an economical and efficient soil washing system. The proper selection of type and dosage of flocculants is crucial to the success of the fine treatment. This paper describes and proposes a new theory to determine the optimum dosage of flocculants (polymers) based on the soil plasticity index and the pH value. This theory concerning the optimum dosage was verified by subsequent data in the soil washing plant.

  • 繰り返し載荷実験による関東ロームで埋戻した道路の沈下量予測

    南形英孝, 吉崎浩司, 萩原直人, 赤木寛一

    土木学会舗装工学論文集   11   1 - 8  2006.12

  • 土の塑性指数とpHに着目した土壌洗浄における凝集沈殿・脱水プロセス管理

    赤木寛一, 毛利光男, 田中仁志, 石田聖一

    土木学会論文集G   vol.62 ( No.3 ) 359 - 368  2006.09

  • 下水汚泥焼却灰を添加した新埋戻し材の埋戻し技術

    基礎工   Vol.34, ( No.2, ) pp24  2006.02

  • Settlement behaviour of a shield tunnel constructed in subsiding reclaimed area

    K. Komiya, K. Takiyama, H. Akagi

    GEOTECHNICAL ASPECTS OF UNDERGROUND CONSTRUCTION IN SOFT GROUND   pp.239-244   239 - +  2006  [Refereed]

     View Summary

    This paper focuses on a large settlement behaviour of a shield tunnel, which is constructed in soft alluvial clay strata beneath fresh reclaimed land. The total settlement of the tunnel is more than 0.73 metres and the deformation takes place over more than twenty years after the completion of the tunnel construction. Three dimensional finite element analyses have been carried out to estimate a long-term behaviour of soil and tunnel structure observed in this field. The computed vertical settlement of tunnel structure is compared with the measured data.

  • Cost reduction of diaphragm wall excavation using air foam

    Yoshimasa Kondo, Takashi Nakayama, Hisanaga Naoe, Hirokazu Akagi

    GEOTECHNICAL ASPECTS OF UNDERGROUND CONSTRUCTION IN SOFT GROUND   pp.413-418   413 - +  2006  [Refereed]

     View Summary

    A novel stabilizing liquid using air foam rather than bentonite clay slurry, i.e. air foam suspension, is employed in order to stabilize the trench wall surface during a diaphragm wall excavation. Air foam suspension is used to reduce the construction costs of working on an underground diaphragm wall. Air foam suspension is created by mixing the excavated soil with air foam made from a surface-active chemical agent. The performance of air foam suspension depends on its density and consistency, that is, its table flow value (TF). By comparing the trench stabilization capacity of air foam suspension with that of bentonite clay slurry in model tests, the appropriate performance of air foam suspension was confirmed. The cost evaluation of using an air foam suspension for a diaphragm wall excavation is presented.

  • Cost reduction of diaphragm wall excavation using air foam

    Yoshimasa Kondo, Takashi Nakayama, Hisanaga Naoe, Hirokazu Akagi

    GEOTECHNICAL ASPECTS OF UNDERGROUND CONSTRUCTION IN SOFT GROUND   pp.68-74   413 - +  2006  [Refereed]

     View Summary

    A novel stabilizing liquid using air foam rather than bentonite clay slurry, i.e. air foam suspension, is employed in order to stabilize the trench wall surface during a diaphragm wall excavation. Air foam suspension is used to reduce the construction costs of working on an underground diaphragm wall. Air foam suspension is created by mixing the excavated soil with air foam made from a surface-active chemical agent. The performance of air foam suspension depends on its density and consistency, that is, its table flow value (TF). By comparing the trench stabilization capacity of air foam suspension with that of bentonite clay slurry in model tests, the appropriate performance of air foam suspension was confirmed. The cost evaluation of using an air foam suspension for a diaphragm wall excavation is presented.

  • Cost reduction of diaphragm wall excavation using air foam

    Yoshimasa Kondo, Takashi Nakayama, Hisanaga Naoe, Hirokazu Akagi

    GEOTECHNICAL ASPECTS OF UNDERGROUND CONSTRUCTION IN SOFT GROUND   pp685-692   413 - +  2006  [Refereed]

     View Summary

    A novel stabilizing liquid using air foam rather than bentonite clay slurry, i.e. air foam suspension, is employed in order to stabilize the trench wall surface during a diaphragm wall excavation. Air foam suspension is used to reduce the construction costs of working on an underground diaphragm wall. Air foam suspension is created by mixing the excavated soil with air foam made from a surface-active chemical agent. The performance of air foam suspension depends on its density and consistency, that is, its table flow value (TF). By comparing the trench stabilization capacity of air foam suspension with that of bentonite clay slurry in model tests, the appropriate performance of air foam suspension was confirmed. The cost evaluation of using an air foam suspension for a diaphragm wall excavation is presented.

  • Recent Developments of Geotechnical Engineering in Soft ground

    Proc. of the 2nd China-Japan Geotechnical Symposium/Tongji Univ. press    2005.10

  • 土壌洗浄濃縮残渣の脱水圧密特性から見た高分子凝集剤の性能

    土木学会第60回年次学術講演会概要集/土木学会   pp.221-222  2005.09

  • 自在ボーリングを用いた地盤改良工法による海産生物に対する安全性について

    土木学会第60回年次学術講演会概要集/土木学会   pp,563-564  2005.09

  • 下水汚泥焼却灰を利用した流動化処理土の強度特性と配合設計

    土木学会第60回年次学術講演会概要集/土木学会   pp,747-748  2005.09

  • コーン試験による建設発生土の埋戻し判定方法の現場試験による検証

    土木学会第60回年次学術講演会概要集/土木学会   pp,797-798  2005.09

  • MRP土木洗浄プロセスにおける汚染物質の分離

    水環境学会誌   28巻 ( 9号 ) 589 - 594  2005.08

  • 薬液注入による固結砂の長期耐久性と強度について

    第40回地盤工学研究発表会講演集/地盤工学会   pp,755-756  2005.07

  • 埋戻し土の分類と埋戻し特性の評価に関する簡易判定技術の開発

    第40回地盤工学研究発表会講演集/地盤工学会   pp,844-845  2005.07

  • 植物の生育状況からみた高アルカリ建設発生土の中和による土壌性能の改良

    第40回地盤工学研究発表会講演集/地盤工学会   pp,2685-2686  2005.07

  • 自在ボーリングを用いた薬液注入工法の液状化対策への適用—海産生物(アマモとアサリ)に対する安全性について—

    第40回地盤工学研究発表会講演集/地盤工学会   pp,2715-2716  2005.07

  • 時間係数を用いた液状化土の粘性抵抗の回復評価

    第40回地盤工学研究発表会講演集/地盤工学会   pp,2241-2242  2005.07

  • 下水汚泥焼却灰中のリンが流動化処理土の強度特性に及ぼす影響

    第40回地盤工学研究発表会講演集/地盤工学会   pp,599-600  2005.07

  • 汚染土壌懸濁液の沈降速度からみた凝集剤の性能評価

    第40回地盤工学研究発表会講演集/地盤工学会   pp,2673-2674  2005.07

  • Mitigating measures for underground construction in soft ground

    Proc. of the 5th International Conference of TC28 of The ISSMGE, /Taylor &amp; Francis   pp.55-60  2005.06

  • 有限要素法を用いた地下構造物の資産価値評価の試み

    土木学会第59回年次学術講演会概要集/土木学会   pp.551-552  2004.09

  • 薬液注入による液状化対策を目的とした固結砂の長期耐久性について

    土木学会第59回年次学術講演会概要集/土木学会   pp. 1035-1036  2004.09

  • 沈殿物の圧密特性からみた凝集剤の性能評価

    土木学会第59回年次学術講演会概要集/土木学会   pp.93-94  2004.09

  • 石膏を添加した地盤掘削用気泡安定液固化物の強度特性

    土木学会第59回年次学術講演会概要集/土木学会   pp. 1005-1006  2004.09

  • 浸透圧密を利用した焼却飛灰の洗浄効果にpH が及ぼす影響

    土木学会第59回年次学術講演会概要集/土木学会   pp. 617-618  2004.09

  • 土木洗浄における液体サイクロン系統のモデル化

    水環境学会誌   第27巻,第8号,pp.535-540  2004.08

  • 薬液注入を利用した液状化対策とその長期耐久性について

    第39回地盤工学研究発表会講演集/地盤工学会   pp. 1013-1014  2004.07

  • 粘土懸濁液の沈降速度からみた凝集剤の性能評価

    第39回地盤工学研究発表会講演集/地盤工学会   pp. 2247-2248  2004.07

  • 地盤掘削用気泡安定液におけるブリージング管理

    第39回地盤工学研究発表会講演集/地盤工学会   pp. 1593-1594  2004.07

  • 植物生育状況から見た高アルカリ建設発生土の中和による土壌性能の改良

    第39回地盤工学研究発表会講演集/地盤工学会   pp. 805-806  2004.07

  • 凝集剤を併用した浸透圧密による建設汚泥の脱水処理について

    第39回地盤工学研究発表会講演集/地盤工学会   pp. 2249-2250  2004.07

  • RATIONAL DESIGN METHOD OF HOT MIX ASPHALT BASED ON CALCULATED VMA

    Proc. 3rd Eurasphalt &amp; Eurobitume Congress 2004/ Foundation Euraspahlt     pp.1956 - 1966  2004.05

  • 時間係数を用いた液状化土の粘性評価について

    第39回地盤工学研究発表会講演集/地盤工学会   pp. 1955-1956  2004.04

  • 地盤工学的視点からみた日本における最近の地下建設事情

    土と基礎/地盤工学会   Vol.52 No.3 Ser.No.554  2004.03

  • Geotechnical Aspects of Current Underground Construction in Japan

    Journal of the Japanese Geotechinical society/ Japanese Geotechnical society   Vol.44 No.1, pp.1-24.  2004.02

  • Geotechnical aspects of current underground construction in Japan

    H Akagi

    SOILS AND FOUNDATIONS   44 ( 1 ) 1 - 24  2004.02  [Refereed]

     View Summary

    The Japanese National Committee for TC28 has produced a committee report on current underground construction activities in Japan, including the technologies of braced excavation and tunneling.
    This report is based on technical papers and available construction records from the past decade. In the field of braced excavation, the topics of proximity construction, excavation machines for braced walls, deep shaft excavation, and groundwater flow preservation measures have been selected and introduced, along with some case records. In the field of tunneling, statistical data on tunneling in Japan has been assembled from published data and questionnaires. Several case records using current shield tunneling and urban NATM methods are described. Finally, damages to underground structures due to the 1995 Hyogoken-Nanbu (Kobe) Earthquake are summarized, and new earthquake-resistant designs for shield tunneling and other technologies are introduced.

  • Geotechnical aspects of current underground construction in Japan

    Hirokazu Akagi

    Soils and Foundations   44 ( 1 ) 1 - 24  2004

     View Summary

    The Japanese National Committee for TC28 has produced a committee report on current underground construction activities in Japan, including the technologies of braced excavation and tunneling. This report is based on technical papers and available construction records from the past decade. In the field of braced excavation, the topics of proximity construction, excavation machines for braced walls, deep shaft excavation, and groundwater flow preservation measures have been selected and introduced, along with some case records. In the field of tunneling, statistical data on tunneling in Japan has been assembled from published data and questionnaires. Several case records using current shield tunneling and urban NATM methods are described. Finally, damages to underground structures due to the 1995 Hyogoken-Nanbu (Kobe) Earthquake are summarized, and new earthquake-resistant designs for shield tunneling and other technologies are introduced.

    DOI

    Scopus

    4
    Citation
    (Scopus)
  • Proceedings of the Sino-Japanese Symposium on Geotechnical Engineering

    Tsingha University Press    2003.10

  • Proceedings of the Sino-Japanese Symposium on Geotechnical Engineering

    Tsingha University Press    2003.10

  • 有限要素法によるシールドトンネル縦断方向挙動の予測と伸縮継手目開き量について

    土木学会第58回年次学術講演概要集/土木学会   pp. 851-852  2003.09

  • 薬液で固結させた砂の長期耐久性について

    土木学会第58回年次学術講演概要集/土木学会   pp 1141-1142  2003.09

  • 地盤掘削用気泡安定液の連続地中壁工法への適用について

    土木学会第58回年次学術講演概要集/土木学会   pp. 1221-1222  2003.09

  • 浸透圧密を利用した焼却飛灰の洗浄効果について

    土木学会第58回年次学術講演概要集/土木学会   pp 121-122  2003.09

  • 建設発生土のコンポスト化を利用した土壌性能の改良

    土木学会第58回年次学術講演概要集/土木学会   pp. 359-360  2003.09

  • 液状化土の粘性評価とそれに基づく液状化地盤の側方流動シミュレーション

    土木学会第58回年次学術講演概要集/土木学会   pp 717-718  2003.09

  • 有限要素法によるシールド縦断方向挙動の予測と伸縮継手目開き量について

    第38回地盤工学研究発表会講演集/地盤工学会   pp. 1689-1690  2003.07

  • 薬液で固結させた砂の長期耐久性について

    第38回地盤工学研究発表会講演集/地盤工学会   pp 1019-1020  2003.07

  • 中空ねじりせん断試験による液状化土の粘性評価について

    第38回地盤工学研究発表会講演集/地盤工学会   pp. 2015-2016  2003.07

  • 浸透圧密を利用した建設発生汚泥の脱水処理について

    第38回地盤工学研究発表会講演集/地盤工学会   pp. 2301-2302  2003.07

  • 建設発生土のコンポスト化を利用した土壌性能の改良に関する実験的研究

    第38回地盤工学研究発表会講演集/地盤工学会   pp. 2397-2398  2003.07

  • 起泡剤を用いた地盤掘削用安定液の性状管理

    第38回地盤工学研究発表会講演集/地盤工学会   pp. 1527-1528  2003.07

  • 気泡を利用した地中連続掘削用安定液の開発とコスト評価

    基礎工   Vol.31, ( No.7, ) 22 - 25  2003.07

  • Experimental Evaluation of Viscid Properties of Liquefied Sand

    Proceedings of the Eighth U.S.-Japan Workshop on Earthquake Resistant Design of Lifeline Facilities and Countermeasures Against Liquefaction   pp.405-412  2002.12

  • Experimental Evaluation of Viscid Properties of Liquefied Sand

    Proceedings of the Eighth U.S.-Japan Workshop on Earthquake Resistant Design of Lifeline Facilities and Countermeasures Against Liquefaction   pp.405-412  2002.12

  • Geotechnical aspects of current underground construction in Japan

    IS-Toulouse, Underground construction in soft ground, TC28, ISSMGE    2002.10

  • 浸透圧密を利用した建設汚泥の脱水処理について

    土木学会第57回年次学術講演概要集/土木学会   pp. 717-718  2002.09

  • 起泡材を用いた地盤掘削用安定液の圧力と地下水との差圧について

    土木学会第57回年次学術講演概要集/土木学会   pp. 249-250  2002.09

  • 薬液充てん率に基づく注入工法の性能評価について

    第37回地盤工学研究発表会講演集/地盤工学会   pp. 1129-1130  2002.07

  • 飽和砂地盤における泥水を利用した円形トンネルの安定化

    第37回地盤工学研究発表会講演集/地盤工学会   pp. 1633-1634  2002.07

  • 分級を利用した流動化処理土材料生産システムについて

    第37回地盤工学研究発表会講演集/地盤工学会   pp. 2369-2370  2002.07

  • 地震による液状化土の粘性評価について

    第37回地盤工学研究発表会講演集/地盤工学会   pp. 1997-1998  2002.07

  • 起泡材を用いた地盤掘削用安定液の溝壁安定化機構

    第37回地盤工学研究発表会講演集/地盤工学会   pp. 1523-1524  2002.07

  • Soil consolidation associated with grouting during shield tunnelling in soft clayey ground

    K Komiya, K Soga, H Akagi, MR Jafari, MD Bolton

    GEOTECHNIQUE   51 ( 10 ) 835 - 846  2001.12  [Refereed]

     View Summary

    The effectiveness of grouting to reduce surface settlements during underground construction in clayey ground was investigated by a field trial and laboratory tests. The field trial was carried out during shield tunnelling work conducted in alluvial clay deposits in Koto-ku, Tokyo. Grout was injected at some distance away from the tunnel, and both surface and subsurface settlements above the tunnel were monitored. Although the initial heave was achieved immediately after the grout injection, the ground continued to settle with time, owing to soil consolidation and grout shrinkage. A laboratory investigation was conducted to investigate the parameters that control the long-term behaviour of grouting in clay. It was found that better long-term grout efficiency can be achieved in overconsolidated clay than in normally consolidated clay, and the efficiency increased with increasing injection volume. Finite element analysis of the laboratory experiments confirmed that the amount and extent of excess pore pressures generated during injection govern the longterm grout efficiency. Finite element analysis of the field trial was also performed to simulate the long-term ground deformation after grout injection.

  • 飽和砂地盤における連続地中壁掘削時の溝壁安定について

    土木学会論文集   No. 693/Ⅵ- 53,pp.161-171  2001.12

  • Soil consolidation associated with grouting during shield tunnelling in soft clayey ground

    K Komiya, K Soga, H Akagi, MR Jafari, MD Bolton

    GEOTECHNIQUE   51 ( 10 ) 835 - 846  2001.12  [Refereed]

     View Summary

    The effectiveness of grouting to reduce surface settlements during underground construction in clayey ground was investigated by a field trial and laboratory tests. The field trial was carried out during shield tunnelling work conducted in alluvial clay deposits in Koto-ku, Tokyo. Grout was injected at some distance away from the tunnel, and both surface and subsurface settlements above the tunnel were monitored. Although the initial heave was achieved immediately after the grout injection, the ground continued to settle with time, owing to soil consolidation and grout shrinkage. A laboratory investigation was conducted to investigate the parameters that control the long-term behaviour of grouting in clay. It was found that better long-term grout efficiency can be achieved in overconsolidated clay than in normally consolidated clay, and the efficiency increased with increasing injection volume. Finite element analysis of the laboratory experiments confirmed that the amount and extent of excess pore pressures generated during injection govern the longterm grout efficiency. Finite element analysis of the field trial was also performed to simulate the long-term ground deformation after grout injection.

  • 泥水式シールド掘進における泥水圧が既設線状構造物に及ぼす影響について

    土木学会第56回年次学術講演概要集/土木学会   pp. 190-191  2001.10

  • 骨材間隙率に基づく加熱アスファルト混合物の容積配合設計法の提案

    土木学会舗装工学論文集   第5巻  2000.12

  • 図説土木工学基礎講座「土質力学」

    彰国社    2000.10

  • 薬液の限界注入速度決定の問題点とその改善に関する研究

    土木学会論文集   No.658/Ⅵ-48,pp.81-92  2000.09

  • 粘性材料の注入に伴う乾燥砂の亀裂現象について

    土木学会第55回年次学術講演概要集/土木学会    2000.09

  • 泥水式シールドのスリット開口率が砂地盤の間隙水圧とカッター圧に及ぼす影響

    土木学会第55回年次学術講演概要集/土木学会    2000.09

  • 泥水式シールドにおける泥膜形成が周知地盤の安定に及ぼす影響

    土木学会第55回年次学術講演概要集/土木学会    2000.09

  • 骨材粒度に基づく加熱アスファルト混合物の骨材間隙率推定法に関する研究

    土木学会論文集   No.648/Ⅴ-47,pp.191〜202  2000.05

  • 第6編第4章 土の定ひずみ速度載荷による圧密試験

    土質試験の方法と解説—第一回改訂版—,地盤工学会   389-409  2000.03

  • Displacement of saturated sand during slurry shield driving

    K Hosokawa, H Akagi

    GEOTECHNICAL ASPECTS OF UNDERGROUND CONSTRUCTION IN SOFT GROUND   Vol.1 391-396   391 - 396  2000  [Refereed]

     View Summary

    The aim of this study is to develop a laboratory ground movement measuring device and apply it to a model test of shield tunneling. The thin flexible metal plate was used for measuring ground displacement, to which the strain gauges were affixed. The calibrations of soil displacement obtained from this measuring device were carried out by the trap door tests. The potential of the laboratory ground movement measuring device was demonstrated for the use to measure the ground displacement during shield driving. Furthermore, a series of model tests were carried out to investigate the ground displacement behaviour during shield machine driving.

  • Bored tunnelling - TBM and shield tunnelling

    H Akagi

    GEOTECHNICAL ASPECTS OF UNDERGROUND CONSTRUCTION IN SOFT GROUND   Vol.1, 33-38   33 - 38  2000  [Refereed]

     View Summary

    This general report reviews and examines 27 papers submitted to the session on TBM (tunnel boring machine) and Shield Tunnelling, as a risk management system.

  • 加熱アスファルト混合物の骨材間隙率の検討

    土木学会舗装工学論文集   第4巻  1999.12

  • 飽和砂地盤の泥水式シールド工法におけるトンネル土圧について

    第54回土木学会年次学術講演会講演概要集/土木学会   3B  1999.09

  • 泥水式シールド掘進における取り込み土量と地中変位の関係について

    第54回土木学会年次学術講演会講演概要集/土木学会   3B  1999.09

  • 注入に伴う飽和砂の割裂現象と割裂圧について

    第54回土木学会年次学術講演会講演概要集/土木学会   3B  1999.09

  • 建設汚泥フロックの圧密応答による脱水性の評価について

    第54回土木学会年次学術講演会講演概要集/土木学会   3B  1999.09

  • 建設汚泥の対流を利用したピット内分級処理について

    第54回土木学会年次学術講演会講演概要集/土木学会   3B  1999.09

  • 飽和粘性土地盤における杭貫入プロセスの有限要素法シミュレーション

    第34回地盤工学研究発表会講演集/地盤工学会   2/2  1999.07

  • 飽和砂の目詰まりに基づく割裂現象について

    第34回地盤工学研究発表会講演集/地盤工学会   2/2  1999.07

  • 泥水式シールド掘進における泥水圧が飽和砂地盤の地中変位に及ぼす影響

    第34回地盤工学研究発表会講演集/地盤工学会   2/2  1999.07

  • 建設汚泥の低応力レベルにおける脱水特性の定量的評価について

    第34回地盤工学研究発表会講演集/地盤工学会   2/2  1999.07

  • 温水洗浄による石炭灰の無害化に関する基礎的研究—六価クロムの除去・回収効果について—

    第34回地盤工学研究発表会講演集/地盤工学会   2/2  1999.07

  • Finite element simulation of excavation and advancement processes of a shield tunnelling machine

    Soils and Foundations, Japanese Geotechnical Society   Vol.39, No.3, 37-52  1999.06

  • 3.4.10 掘削による地盤の変形問題の考え方と解き方

    地盤工学ハンドブック,地盤工学会   135-142  1999.03

  • Finite element modelling of excavation and advancement processes of a shield tunnelling machine

    Kazuhito Komiya, Kenichi Soga, Hirokazu Akagi, Toshiyuki Hagiwara, Malcolm D. Bolton

    Soils and Foundations   39 ( 3 ) 37 - 52  1999

     View Summary

    During shield tunnelling operation, a shield machine is driven forward by applying mechanical jack forces behind the machine tail and excavating the soil in front of the machine with its cutting face. In this study, the advancement and excavation processes of the shield tunnelling operation are modelled using the finite element method in order to investigate the effect of these construction processes on the ground response. A new excavating finite element, which models the disturbed soil in front of the cutting face, is introduced. The operation of shield advancement and of soil excavation is simulated using the finite element remeshing technique at each time step of the analysis. The accuracy of the finite element remeshing technique is discussed by analysing one-dimensional consolidation of an isotropic elastic medium. The proposed modelling techniques of shield tunnelling construction are applied to simulate a tunnelling project in Tokyo and the numerical results are compared with the field measurements. The soil deformation mechanism associated with the shield tunnelling operation is examined in detail.

    DOI

    Scopus

    85
    Citation
    (Scopus)
  • Finite element modelling of excavation and advancement processes of a shield tunnelling machine

    Kazuhito Komiya, Kenichi Soga, Hirokazu Akagi, Toshiyuki Hagiwara, Malcolm D. Bolton

    Soils and Foundations   39 ( 3 ) 37 - 52  1999

     View Summary

    During shield tunnelling operation, a shield machine is driven forward by applying mechanical jack forces behind the machine tail and excavating the soil in front of the machine with its cutting face. In this study, the advancement and excavation processes of the shield tunnelling operation are modelled using the finite element method in order to investigate the effect of these construction processes on the ground response. A new excavating finite element, which models the disturbed soil in front of the cutting face, is introduced. The operation of shield advancement and of soil excavation is simulated using the finite element remeshing technique at each time step of the analysis. The accuracy of the finite element remeshing technique is discussed by analysing one-dimensional consolidation of an isotropic elastic medium. The proposed modelling techniques of shield tunnelling construction are applied to simulate a tunnelling project in Tokyo and the numerical results are compared with the field measurements. The soil deformation mechanism associated with the shield tunnelling operation is examined in detail.

    DOI

    Scopus

    85
    Citation
    (Scopus)
  • 粒状体裏込め地盤の地震時の流動特性について

    第53回土木学会年次学術講演会/土木学会    1998.10

  • 有機系高分子凝集剤による粘土フロックの圧密脱水特性

    第53回土木学会年次学術講演会/土木学会    1998.10

  • 飽和粘性土地盤の杭打設に伴う地盤変形の有限要素法シミュレーション

    第53回土木学会年次学術講演会/土木学会    1998.10

  • 飽和砂地盤の薬液注入における割裂現象の発生条件

    第53回土木学会年次学術講演会/土木学会    1998.10

  • 大型土槽における泥水シールド模型の掘進実験について

    第53回土木学会年次学術講演会/土木学会    1998.10

  • 小型地中変位計のシールド模型実験への適用について

    第53回土木学会年次学術講演会/土木学会    1998.10

  • 有機系高分子凝集剤による湖底底質の沈降特性

    第33回地盤工学研究発表会/地盤工学会    1998.07

  • 粘土懸濁液の有機系凝集剤による凝集沈降特性についてについて

    第33回地盤工学研究発表会/地盤工学会    1998.07

  • 気泡と高吸水性ポリマーによる安定処理土の基本性状について

    第33回地盤工学研究発表会/地盤工学会    1998.07

  • シールド掘進に伴う地盤挙動のFEM解析システムの開発

    第33回地盤工学研究発表会/地盤工学会    1998.07

  • Sedimentation and consolidation of lake-bottom deposits with an organic flocculant

    Y Sugawara, H Akagi, H Komine

    ENVIRONMENTAL GEOTECHNICS, VOLS 1-4   1,PP.359-364   359 - 364  1998  [Refereed]

     View Summary

    In closed water environments such as lakes or marshes, soil and organic materials deposit at the bottom. In order to solve problems of land smells or water pollution, bottom deposits have been dredged or stabilized with cement. Recently, the reuse of lake-bottom deposits for agricultural compost has been planned, but an efficient flocculation and dewatering method for high water content lake deposits is necessary for this to be implemented. In this study, a series of sedimentation experiments and consolidation tests on lake-bottom deposits dredged from a closed water environment lake were carried out using an organic flocculant. It is shown from the experimental results that an optimum volume of flocculant does exist for efficient sedimentation and that the addition of flocculant improves the dewatering characteristics of lake-bottom deposits.

  • 有機系高分子凝集剤を添加した底質の凝集沈降特性および圧密脱水特性に関する研究

    第2回環境地盤工学シンポジウム発表論文集/地盤工学会   1; pp.193-198  1997.11

  • 飽和粘性土地盤の杭打設模型実験と有限要素法シミュレーション

    土木学会第52回年次学術講演会講演概要集/土木学会   3;A  1997.09

  • 飽和砂地盤における泥水シールド掘進に伴う地盤挙動の有限要素法シミュレーション

    土木学会第52回年次学術講演会講演概要集/土木学会   3;A  1997.09

  • 有機系高分子凝集剤による底質懸濁液の沈降特性に関する研究

    第32回地盤工学研究発表会講演集/地盤工学会   2;1  1997.07

  • 飽和砂地盤の泥水シールド掘削時の切羽の安定と周辺地盤の応力状態に影響を及ぼす要因

    第32回地盤工学研究発表会講演集/地盤工学会   2;2  1997.07

  • 砂地盤の薬液注入における割裂発生条件について

    第32回地盤工学研究発表会講演集/地盤工学会   2;2  1997.07

  • 砂地盤におけるアルカリ物質の溶出拡散過程の二次元模型実験と解析

    第32回地盤工学研究発表会講演集/地盤工学会   2;1  1997.07

  • 砂質地盤の薬液注入における割裂内部の圧力変化

    第32回地盤工学研究発表会講演集/地盤工学会   2;2  1997.07

  • Finite element analyses of the interaction of a pair of shield tunnels

    H Akagi, K Komiya

    FOURTEENTH INTERNATIONAL CONFERENCE ON SOIL MECHANICS AND FOUNDATION ENGINEERING, VOL 3   Vol.3, pp.1449-1452   1449 - 1452  1997  [Refereed]

     View Summary

    This paper introduces a numerical simulation procedure for use with the shield tunnelling problems and compares the simulation results with field measurements for soft clay ground. The shield machine advance is simulated numerically by adopting excavation elements and repetitively rearranging the three-dimensional finite element mesh used in the simulation. Deformation of soft clay ground and the effective stress behaviour as the shield machine advances under actual hydraulic jacking forces are modelled successfully by the new procedure. As an example, the application of this procedure to the twin shield tunnelling problem is described.

  • Finite element analyses of the interaction of a pair of shield tunnels

    H Akagi, K Komiya

    FOURTEENTH INTERNATIONAL CONFERENCE ON SOIL MECHANICS AND FOUNDATION ENGINEERING, VOL 3   3; pp.1449-1452   1449 - 1452  1997  [Refereed]

     View Summary

    This paper introduces a numerical simulation procedure for use with the shield tunnelling problems and compares the simulation results with field measurements for soft clay ground. The shield machine advance is simulated numerically by adopting excavation elements and repetitively rearranging the three-dimensional finite element mesh used in the simulation. Deformation of soft clay ground and the effective stress behaviour as the shield machine advances under actual hydraulic jacking forces are modelled successfully by the new procedure. As an example, the application of this procedure to the twin shield tunnelling problem is described.

  • Stress-dilatancy relation of undisturbed clay under principal axes rotation

    H Akagi, H Yamamoto

    DEFORMATION AND PROGRESSIVE FAILURE IN GEOMECHANICS - IS-NAGOYA'97   1; pp.212-216   211 - 216  1997  [Refereed]

     View Summary

    Drained torsion shear tests of anisotropically consolidated undisturbed clay were carried out using hollow cylindrical specimens, in order to investigate the effects of principal axes rotation particularly on the dilatancy characteristics of undisturbed clay. The magnitude of dilatancy is considered to represent the microstructural change of undisturbed clay during the drained torsion shear process. The plastic volumetric strain of clay was experimentally observed to occur just due to the principal axes rotation under constant mean principal stress p' and principal stress difference q drained shear conditions. The plastic Volumetric strain increment of undisturbed clay under a magnitude of principal axes rotation was found to be greater than that of reconstituted clay.

  • 不攪乱粘土の主応力軸回転時の応力-ダイレイタンシー特性

    第51回年次学術講演会概要集/土木学会   3-A  1996.09

  • セメント・石灰系固化材による粘土スラリーの固化・強度特性とpH変化

    第51回年次学術講演会概要集/土木学会   3-B  1996.09

  • 砂質地盤の薬液注入における割裂脈内の圧力変化

    第31回地盤工学研究発表会講演集/地盤工学会   2  1996.07

  • ベントナイト泥水を含む土-セメント混合物の強度特性

    第31回地盤工学研究発表会講演集/地盤工学会   2  1996.07

  • Finite element simulation of shield tunnelling processes in soft ground

    H Akagi, K Komiya

    GEOTECHNICAL ASPECTS OF UNDERGROUND CONSTRUCTION IN SOFT GROUND     447 - 452  1996  [Refereed]

     View Summary

    This paper introduces a numerical simulation procedure for use with the shield tunnelling problems and compares the simulation results with field measurements for soft clay ground. Shield machine advance is simulated numerically by adopting excavation elements and repetitively rearranging the three-dimensional finite element mesh used in the simulation. Deformation of soft clay ground and the pore water pressure behaviour as the shield machine advances under actual hydraulic jacking forces are modelled successfully by the new procedure. As an example; the application of this procedure to tile twin shield tunnelling problem is described.

  • Slurry composition effects on soil-cement mixtures

    H Akagi, H Nakazato

    ENVIRONMENTAL GEOTECHNICS, VOL 2   2   687 - 690  1996  [Refereed]

     View Summary

    Soil-cement mixtures were prepared using three types of materials sandy soil excavated from a shield tunnelling construction site in Tokyo, clay slurry used for stabilizing the shield tunnel cutting face, and cement. These soil-cement mixtures were planned to be used for the filling of the lower part (invert section) of the circular shield tunnel cross-section in place of cement mortar. A number of unconfined compression tests were carried out to investigate the time-dependent variation of compressive strength of soil-cement mixtures. The strength of soil-cement mixture was found to be satisfactory as the new invert material and to be influenced by the contents of the clay slurry. It could be seen that the density of soil-cement mixtures measured immediately after mixing and compaction was directly related to the compressive strength.

  • 飽和砂中の割裂脈内の圧力低下について

    土木学会第50回年次学術講演会講演概要集/土木学会   3;A  1995.09

  • 主応力軸の回転を伴うせん断による正規圧密粘土の微視的構造変化

    土木学会第50回年次学術講演会講演概要集/土木学会   3;A  1995.09

  • Finite element simulation of sand indentation into saturated soft clay

    Cambridge University Engineering Department   CUED/D-Soils/TR287  1995.08

  • Finite Element Simulation of Sand Indentation into Saturated Soft Clay

    Technical Report of Cambridge University Engineering Department/Cambridge University Engineering Department   CUED/D-Soils/TR287  1995.08

  • Constant rate of strain consolidation properties of clayey soil at high temperature

    H AKAGI, K KOMIYA

    COMPRESSION AND CONSOLIDATION OF CLAYEY SOILS, VOL 1   1   3 - 8  1995  [Refereed]

  • A physico-chemical approach to the consolidation mechanism of soft clays

    Soils and Foundations   Vol.34, No.4, pp.43-50  1994.12

  • Effects of backfilling at shield work in soft cohesive soil

    Proc.11th ICSMFE   Vol.5/A/6, pp.1667-1670  1985.08

▼display all

Books and Other Publications

  • 地盤工学・実務シリーズ28 近接施工

    地盤工学会近接施工編集委員会

    地盤工学会  2011.01 ISBN: 9784886449276

  • 地盤工学における性能設計

    赤木 寛一, 大友 敬三, 田村 昌仁, 小宮 一仁

    丸善(株)出版事業部  2010.01 ISBN: 9784621081785

  • トンネルライブラリー第22号 目から鱗のトンネル技術史 -先達が語る最先端技術への歩み-

    トンネル工学委員会, 技術小委員会, トンネル技術史部会

    土木学会  2009.11 ISBN: 9784810606706

  • 地盤工学・実務シリーズ27 薬液注入工法の理論・設計・施工

    森 麟, 赤木, 寛一, 小宮, 一仁, 村田, 修, 大田, 想三, 田村, 昌仁, 大下 武志

    地盤工学会  2009.07 ISBN: 9784886449269

  • UNDERGROUND CONSTRUCTION TECHNOLOGY IN JAPAN

    Hirokazu Akagi, Kazuhito Komiya, Jamie Standing, Finaly Jardine

    地盤工学会 (The Japanese Geotechnical Society)  2006.08 ISBN: 4886440754

  • 道路工学(共著)

    理工図書  2005.06

  • 図説土木工学基礎講座「土質力学」

    赤木寛一, 小宮一仁

    彰国社  2000.09 ISBN: 4395040233

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Industrial Property Rights

  • 線状構造物の構造計算方法及び構造計算プログラム

    赤木 寛一

    Patent

  • 掘削装置

    赤木 寛一

    Patent

  • 地盤中へのポリマー注入による遮水および透水回復工法

    赤木 寛一

    Patent

  • 切削用組成物及びこれを用いた高圧噴射撹拌工法

    赤木 寛一

    Patent

  • ソイルセメント地中連続壁施工法

    赤木 寛一

    Patent

  • 地盤凍結施工法

    赤木 寛一

    Patent

  • シールド工法用膨潤高吸水性ポリマー安定液組成物及びこれを用いた施工法

    赤木 寛一

    Patent

  • 透水性基礎の構築方法

    6066757

    赤木 寛一

    Patent

  • 山留壁構築工法及びこの山留壁構築工法により構築された山留壁

    6141660

    赤木 寛一

    Patent

  • 地中連続止水壁工法

    6207149

    赤木 寛一

    Patent

  • 地盤掘削用膨潤高吸水性ポリマー安定液組成物及びこれを用いた施工法

    6113433

    赤木 寛一

    Patent

  • 地盤改良工法

    5898889

    赤木 寛一

    Patent

  • 規格気泡安定液による地下構造物の造成方法

    5676897

    赤木 寛一

    Patent

  • 気泡安定液の調整方法と気泡掘削施工法

    4970547

    赤木 寛一

    Patent

  • 段階式固化施工法

    5513182

    赤木 寛一

    Patent

  • ソイルセメント柱およびソイルセメント連続壁の造成方法

    5317938

    赤木 寛一

    Patent

  • 遮水壁の固化材の配合設計方法

    4703575

    赤木 寛一, 内田 俊

    Patent

  • 遮水壁の構築方法

    4342558

    赤木 寛一

    Patent

  • 安定液組成物

    3725750

    赤木 寛一

    Patent

▼display all

Other

  • Connection...

     View Summary

    Connection among academic, industrial and public institutes are aimed by conducting the broad research activities on soil soil mechanics and environmental geotechnics. The students shall be stimulated by the active research connection mentioned above.

  • Connection among academic, industrial and public institutes are aimed by conducting the broad research activities on soil soil mechanics and environmental geotechnics. The students shall be stimulated by the active research connection mentioned above.

Awards

  • 地盤工学会功労章

    2010.03  

  • 土木学会論文賞

    2007.05  

Research Projects

  • 再生石膏を利用した中間処理技術の調査研究

    Project Year :

    2012
    -
     
     

  • 気泡掘削による深層地盤改良に関わる基礎的研究

    Project Year :

    2012
    -
     
     

  • 高吸水性ポリマー安定液を使用した掘削技術の開発

    Project Year :

    2012
    -
     
     

  • アスファルト舗装が車輌輪荷重による都市ガス供給用導管土圧に及ぼす影響

    Project Year :

    2012
    -
     
     

  • 薬液で固結させた劣化メカニズムの研究と弾性波測定による効果確認の研究

    Project Year :

    2011
    -
     
     

  • 拘束圧載荷土槽を用いた動的注入の効果に関する基礎的研究

    Project Year :

    2010
    -
    2011
     

  • 注入地盤の経年変化に関する研究

    Project Year :

    2009
    -
    2010
     

  • 数値解析によるガス導管の腐食孔,亀裂部に作用する土圧評価

    Project Year :

    2008
    -
    2010
     

  • 気泡掘削液の現場打杭施工への応用研究

    Project Year :

    2009
    -
     
     

  • 掘削用安定液の高圧下での挙動等に関する研究

    Project Year :

    2009
    -
     
     

  • 気泡掘削液の現場打杭施工への応用研究

    Project Year :

    2009
    -
     
     

  • 薬液注入剤がコンクリートに及ぼす影響の研究

    Project Year :

    2008
    -
     
     

  • 関東ロームを利用したガス導管埋戻し技術に関する研究

    Project Year :

    2007
    -
    2008
     

  • エレメント推進・けん引工法のシミレーション解析

    Project Year :

    2007
    -
    2008
     

  • 住宅基礎地盤改良最適選定システムの開発

    Project Year :

    2007
    -
    2008
     

  • 13号線建設工事に伴う新埋戻し材の実験

    Project Year :

    2004
    -
    2008
     

  • 薬液注入工法の固結後の透水係数と液状化抵抗の関係ほか

    Project Year :

    2007
    -
     
     

  • 建設業請負拡大のための基礎的研究及びデータ収集調査

    Project Year :

    2007
    -
     
     

  • 建設発生土を利用した都市ガス導管埋戻し技術に関する研究

    Project Year :

    2006
    -
    2007
     

  • 海外の地下利用に関するプロジェクトおよび技術の動向調査と分析業務委託

    Project Year :

    2002
    -
    2003
     

  • セメント系固化材混合処理による地盤の液状化防止効果

    Project Year :

    1998
    -
    2003
     

  • Long Term Durability of Chemical Grouting

    Project Year :

    2000
     
     
     

  • Quality Assessment of Chemical Grouting

    Project Year :

    2000
     
     
     

  • Shield Tunnel Operation

    Project Year :

    1998
     
     
     

  • 建設発生土の有効利用に関する研究

    Project Year :

    1994
    -
     
     

  • Study on the Behavior of Soft Clays under High Temperature

     View Summary

    Behavior of soft clays under high temperatures of 70-90゚C has been investigated in the present study. Main subjects investigated are :(1) Study of researches conducted on the related subjects. About 300 paper are investigated and analyzed into the data-base.(2) Laboratory investigations are conducted on the micro-structural and macrostuructural behavior of clays under high temperature.(3) Effects of aging and its background mechanism are studied and evaluated.(4) Applications of present study into practical problems are studied. Behaviors of ground around the lime-piles, living wastes, and nuclear wastes are investigated

  • 土の微小変形機構に着目した土質力学の再構築に関する総合的研究

     View Summary

    現代の土質力学の理論体系は、実験室で人工的に再圧密して準備された粘土試料に対する精密な実験結果に基づいて構築されている。しかし近年、自然地盤の粘土の力学特性は、実験室で再圧密した試料のそれとは異なっていることが知られてきた。この違いは、自然地盤が非常に長い時間をかけて形成されているために、その間に化学的結合作用や二次圧密等のいわゆる年代効果を破り、粒子の構造が発達したことによるのであろう。しかし本研究の始まるまで、年代による粒子構造の変化を定量的に評価しようとした試みは存在しなかった。年代効果を実験室で短期間に再現する方法として、粘土を高温で再圧密する方法と化学的結合物質を粘土スラリーに混入して再圧密する方法とが、使用する機器の規格も含め、提案された。これらの内で高温圧密された粘土の挙動は、室温での結果に比べると異なっている。たとえば圧密時の体積収縮が激しく、二次圧密の急速な進展を示すこと、せん断剛性や強度が大きいことなどである。非排水せん断においては間隙水圧上昇が高温圧密によって小さくなること(強度の増加につながる)ことも過去には報告されてきたが、今回、過圧密粘土を用いて実験したところ、逆の結果が得られた。粘土を高温で圧密すると、粘土粒子表面に吸着されている水分子の熱運動のエネルギーが増え、吸着力に打ち勝って自由水化し、遂には外界へ排出されて圧密体積収縮につながる現象が、起りやすくなる。じつは室温でも同じ現象がきわめてゆっくりながらも継続しており、それが二次圧密の本質である、という仮説を立てた。この仮説を検証するために、排出される間隙水の化学分析を行なう既存の試みに加えて、交流電圧を負荷して電気二重層において粘土粒子と吸着水分子との間に作用しているクーロン力を断ち切る試みを行なった。これによって圧密は促進されたが同時に電気抵抗による温度上昇も起こり、温度に独立な観察を行なうには至らなかった。電子顕微鏡写真を使って粘土の微視的構造を探究することは、過去にも例が多い。しかし上述したように微視構造を定量化する方法が存在しなかった。本研究では顕微鏡写真の濃淡分布に着目し、これをスペクトル分析してみた。再圧密粘土および高温圧密粘土の水平/鉛直断面の写真を撮影し、それをスペクトル分析することによって、粒子の配向構造が検出できることがわかった

  • 強地震動と液状化に対する地中構築物の耐震性に関する研究

     View Summary

    1)大型地中コンクリートダクトの非線型大変形領域から破壊に至るまで載荷実験をもとに,塑性域の挙動を解明し,破壊過程の数値解析モデルを構築して,性能照査型の耐震設計法を提案した.2)譲岸の移動に伴う背後地盤の側方流動のメカニズムを重力場および遠心載荷場での模型実験と既往地震の事例分析により解明し,地表面変位の予測手法を開発した.これによれば,護岸から液状化層の5倍の距離の位置で地盤変位は急速に減衰し、その後一定値に近づくことが示された.平成11〜13年度に開発した傾斜地盤における側方流動の予測手法と併せて.側方流動の総合的な予測法を構築した.3)側方流動が群杭に及ぼす外力特性を重力場および遠心載荷場の模型実験より明らかにした.これによれば,地盤が完全な液状化状態では流動速度に起因する外力が,また不完全な液状化状態では地盤変位に起因する外力が卓越することが示された.以上の結果を総合化して側方流動による杭の変形挙動をシミュレートする解析モデルの構築を行い,耐震設計法を提案した.4)GISを用いて地盤・地形情報をデータベース化し,埋立コンビナート地区など広範な地域を対象とした側方流動予測システムを構築した.本システムを川崎市の埋立コンビナート地区に適用して地盤変位の予測を行った.この結果,埋立年代が比較的古い埋立地で護岸が老朽化している場合には側方流動によって7mを超す水平変位と1m以上の地盤沈下が広範囲にわたって発生することが示され

  • Development of Assessment System for Liquefaction-Induced Ground Flow and Its Caused Damage to Lifeline

     View Summary

    A method for prediction of liquefaction-induced ground deformation was developed based on flow tests of liquefied sand under 1g and centrifuge conditions, as well as on the results from case studies on the ground deformations during past earthquakes such as the 1964 Niigata and Kobe earthquakes. Furthermore, a damage assessment procedure of buried pipes of lifeline systems in liquefiable ground was also developed based on the analyses on the damage to pipelines in Kobe city.On the other hands, a date base of soil conditions and quay wall structures was developed for the assessment of the liquefaction, liquefaction-induced ground deformation and its related damage to buried structure. This data base was practically used for the earthquake disaster prevention measures by the Kanagawa prefectural government

  • Study on the Mechanical Properties of clay floc using Hydraulic Consolidation

     View Summary

    1. Introduction: The construction industry of Japan consumes the half of all the resources, used as construction materials in country. On the other hand, half of the Japanese domestic industrial waste is related to construction industry. In Japan, disposal sites in Japan have insufficient area to accept this waste. Furthermore, each stage of the construction process from the use of resources to the disposal of waste causes significant environmental impact. Construction engineers must find ways of reducing waste and employing various reusable materials. This study aims at developing system for the reuse of construction waste sludge with high water content by using hydraulic consolidation. And the heavy metal content of a discharge and dewatering cake is examined before and after hydraulic consolidation.2. Test condition: The test apparatus is composed mainly of a consolidometer, an upstream tank, a downstream tank, and a compressor. The inside diameter of the consolidometer is 20cm. Water that has passed over a specimen is drained from the lower part of the consolidometer to the downstream tank and the measuring device of water flow is the double tube structure with a central buret and an external part. A compressor creates high air pressure in the upstream tank and low pressure in the downstream tank and air pressure is substituted for hydraulic pressure. A specimen undergoes consolidation due to the seepage force, generated from this difference in pressure.3. Summary: The conclusions derived from this study are as follows:1) An optimum consolidation pressure applied to the sample is 60kPa.2) The effects of washing on lead and zinc are clearly demonstrated in this study

  • Study on Earthquake Resistance of Infrastructures against Fault-Induced Ground Surfece Ruptures

     View Summary

    The purpose of this research are as fellows ;1)The effects of the type of fault ruptures and the characteristics of the sandy deposit on the locations and the magnitudes of the ground surface ruptures are examined by model tests under 1 g and centrifugal conditions, case studies on past earthquake events and numerical analyses by non-linear finite element method.2)A numerical model for large deformation behavior analysis of buried lifeline facilities against fault-induced large ground deformations is developed by model test.The followings were obtained as the outcomes of this research ;1)The confining pressure of the ground strongly governs the location and the magnitude of the fault-induced ground surface ruptures. It was clarified that the model test under an actual high confining pressure by using a centrifuge is essential for this kind of study. The knowledge and the information for the prediction of the location and the magnitude of the ground surface ruptures were accumulated from the centrifuge tests. Those data can be utilized for the establishment of earthquake resistant design of civil engineering structures against fault-induced ground failures.2)A numerical procedure to predict the deformation and the stress of buried pipeline of lifeline systems against large ground failures was developed for the earthquake resistant design

  • Cost reduction of diaphragm wall excavation using air foam and case record

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    A novel stabilizing liquid using air foam rather than bentonite clay slurry, i.e. an air foam suspension method, was employed in order to stabilize the trench wall surface during a diaphragm wall excavation. This method reduces the construction costs of working on an underground diaphragm wall. An air foam suspension is created by mixing excavated soil with air foam made from a surfactant. The performance of the air foam suspension depends on its density and consistency, that is, its table flow value(TF). By comparing the trench stabilization capacity of an air foam suspension with that of bentonite clay slurry in model tests, the performance of air foam suspension was confirmed. A cost evaluation of the use of air foam suspension for diaphragm wall excavation is presented with an actual trial construction case record, which shows the superiority of air foam suspension to bentonite clay slurry as a stabilizing liquid

  • A study on Earthquake Resistance of Foundations against the flow of Liquefied Grond

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    The characteristics of the external forces on the pile foundations from flowing liquefied soil were examined by centrifuge model experiments and numerical analyses. The following results were obtained: The liquid force, resulting from the flow of the liquefied soil is dominant when the ground completely liquefied, while the solid force resulting from the displacement of the liquefied soil was dominant when the ground was in not-perfect liquefaction. The procedure to estimate the external design force was proposed based on the experimental results.On the other hand, the effectiveness of countermeasures to prevent the flow of the liquefied soil behind quaywalls were examined by centrifuge model tests and numerical analyses. Based on the experimental results the procedures for the estimation of design force on countermeasure walls was proposed

  • Asset Evaluation of Underground Infrastructure Using Numerical Method

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Specific Research

  • 有限要素法を用いた地下構造物の資産価値評価法の開発

    2006  

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    これまでわが国では不足する社会資本を建設してきたが、40 年以上経過したストックに老朽化が見られ、更新・補修時期に入っているものが多く存在する。また社会経済状況も変化し、財政的にも厳しい状況の中で、現存する社会資本の効率的な運用・維持管理が重要な課題となっている。その中で社会資本を「資産(アセット)」とみなして、民間企業などで用いられているマネジメント手法を活かそうという動きが起こってきた。例えば、国土交通省では平成15 年度から「道路について、コスト縮減等を目指し、道路の管理手法にアセットマネジメントの考え方等を導入する」とされるなど、その取り組みが始まっている。効率的な維持管理・補修計画を立てるためには、構造物のライフサイクルコストを考えるとともに、現存する社会資本の資産としての価値を適切に評価する必要がある。本研究では地下構造物の資産価値評価法に原価法の考え方を用い、資産価値算定式を提案した。これは構造物の建設費と構造物の物理的な劣化による減価償却に基づくものである。減価償却は、有限要素法を用いて求めた耐用年数により評価した。その適用事例として、沈下未了の軟弱地盤内のシールドトンネルを想定し、初期建設費を100 とした場合には補修費用が51.7 までの範囲内であれば対費用効果が1 を上回ることを実証した。

  • 気泡材を利用した地盤掘削用安定剤の研究開発

    2004  

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    地中連続壁工法は,掘削溝内を安定液で満たし,水中コンクリートを打ち込み,地中に連続した構造物を構築する施工法として発展してきた.これまで,主として用いられてきた地盤掘削用安定液はベントナイト泥水である.本研究では,気泡シールド工法で採用されているような起泡材を用いた気泡安定液の性質を調査し,設計管理手法を確立するとともに,実施工にも適用することを目的とする. 気泡安定液中の気泡量が少ないとき,溝壁と気泡安定液との境界で気泡膜が形成されない為,掘削溝内圧を溝壁に伝えることができない.ベントナイト安定液と同等の内圧を溝壁に伝達できる気泡添加率は,実験から約1.0(%)であることがわかった.また,気泡安定液中の気泡量が多いとき,溝壁に作用する土圧に対抗できない.ベントナイト安定液の比重の下限値を参考にして気泡安定液比重の下限値は10(kN/m3)であり,気泡添加率の上限は約2.0(%)となった. 以上の結果をもとに気泡安定液管理図を作成した.管理図は,気泡添加率と単位体積重量γ,含水比とTF値を対応させた図である.この管理図を用いて試験施工を行った.現場は愛知県,東海環状道路建設に伴う掘削で遮水壁を造成するものである.その結果,気泡安定液による地中連続壁の造成に成功した.セメント添加量300(kg/m3)で,目標強度1.0(N/mm2)を満足するとともに,鋼材の挿入も容易であった.さらに,ベントナイト安定液と比較して,排土量を2分の1に低減することができた. 以上の結果から,気泡安定液を用いた地盤掘削用安定液の施工における実用性が検証された.

  • 浸透圧密試験による粘土フロックの力学性状に関する研究

    2000  

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    現在,建設工事において発生する建設廃棄物はその再利用から処理に至るまでの各段階で自然環境に与える影響が問題となっている.特に近年の廃棄物排出量の増大は,最終処分場の不足や不法投棄などの様々な問題を引き起こしている.この建設廃棄物に属する建設汚泥も例外でなく,高含水比かつ細粒分を多く含む泥状の性質はその処理を困難にさせ,再利用率は年々向上しているものの建設廃棄物全体の中では依然として低い水準にある. こうしたなかで,再利用にあたりその処理過程において重要となる脱水処理には多くの方法が用いられているが,著者らは新しい脱水方法として浸透圧密を利用した脱水処理方法を考案している.しかし,この脱水処理では建設汚泥の粒度条件によっては多大な圧密時間を要することや圧密容器と建設汚泥試料との間に剥離が起きてしまい効果的な脱水を行えないことがある.ここでは,これらの改善策として脱水処理に凝集剤を併用した.本研究では,凝集剤の添加が浸透圧密を用いた建設汚泥の脱水処理性能にどのような影響を及ぼすかを調査し,考察した. 

  • 建設工事に伴う地盤挙動予測システムの開発

    1998  

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     近年、都市の過密化が進み、近接施工が多く行われている。近接施工を行う場合、既設構造物周辺の地盤挙動を予測し、その対策を検討する必要がある。昨今、様々な数値解析が行われているが、そのほとんどが個別の要因を節点外力や節点変位によりモデル化しており、施工プロセスを忠実に再現するには至っていない。本研究では、軟弱地盤における杭打設工事を取り上げ、貫入プロセスを考慮した有限要素法シミュレーションを実施した。 本解析ではBingham流動則によるFEMシミュレーションを実施した。また、同時に、流動FEMプログラムで得られる粘塑性変形の等価節点力を地盤要素に作用させて、圧密解析を行うことにより、杭打設に伴う間隙水圧変化のシミュレーションを実施した。杭周面とそれに接する地盤との間に厚さを持たないGoodman型のジョイント要素を配置し、各計算ステップごとに有限要素の再分割をすることにより、杭の貫入過程のモデル化を行った。地盤要素の上に模型実験で用いられた上載荷重に相当する上載要素を配置した。杭頭の節点に、模型実験における貫入力に相当する節点力を作用させ、6cm貫入時から42cm貫入時まで貫入シミュレーションを行った。なお、地盤要素のヤング率E=100・Cu、塑性粘度μ=1680・Cu、降伏値τy= Cu(Cu:粘性土の非排水せん断強度)とした。また、ジョイント要素の接線方向剛性ksは、杭貫入速度が模型実験で用いられた値となるように設定した。 杭打設シミュレーションにおいて流動FEMプログラムを用いることにより、模型実験でみられた地盤の回転移動が再現された。これは、通常の弾塑性体力学に基礎を置くFEMシミュレーションによっては得ることのできないものである。

  • シールドトンネル工事に伴う地盤沈下予測システムの開発

    1996  

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     本研究は、シールドトンネル工事に伴う地盤沈下のコンピュータシミュレーションによる予測システムの開発を目的として実施した。具体的には、下記のような飽和砂地盤におけるシールド掘進と飽和粘性土地盤における杭打設実験の有限要素法シミュレーションを行った。 1)飽和砂地盤における泥水シールド掘進に伴う地盤挙動の有限要素法シミュレーション 砂地盤における泥水シールド掘進時における切羽の安定に必要な泥水性状および周辺地盤の応力状態の変化のメカニズムを解明することが重要である。ここでは、著者らが開発したシールドトンネル工事における切羽掘削現象の有限要素法によるモデル化手法を砂地盤における泥水シールド掘削問題に適用し、飽和砂地盤における泥水シールド模型の掘進実験の実験結果との比較を行った。その結果、砂地盤における泥水シールド模型掘進の模型実験結果に対応する地盤の応力-間隙水圧挙動のシミュレーション結果を得た。 2)飽和粘性土地盤の杭打設実験の有限要素法シミュレーション 軟弱粘性土地盤の杭打設模型実験結果の有限要素法によるシミュレーションを行った。実験では、飽和粘性土を充填した2次元土槽に貫入速度を一定にして模型杭を打設したときの、杭軸力、杭先端荷重、地表面変位、地中変位、間隙水圧、壁面土圧を測定された。土ー水の連成を考慮した有限要素法解析で非排水条件で外部的に変位を規定された計算を行おうとすると、得られる箇条間隙水圧の値が非現実的な値になる。これを解決するために、変位が規定される境界に隣接する部分に排水状態で変形するBuffer要素を配置して解析を行った。その結果、実験結果に相当する過剰間隙水圧が得られた。

Overseas Activities

  • 環境地盤工学新技術の調査・研究

    2006.03
    -
    2006.09

    ニュージーランド   カンタベリー大学

 

Syllabus

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