Updated on 2026/03/11

写真a

 
OHTSUKA Satoru
 
Organization
Academic Assembly Institute of Science and Technology Specially Appointed Professor
Faculty of Engineering Specially Appointed Professor
Title
Specially Appointed Professor
External link

Degree

  • Doctor of Engineering ( 1989.10   Nagoya University )

Research Interests

  • Geotechnical engineering

  • Disaster Prevention Engineering

Research Areas

  • Social Infrastructure (Civil Engineering, Architecture, Disaster Prevention) / Disaster prevention engineering

  • Social Infrastructure (Civil Engineering, Architecture, Disaster Prevention) / Geotechnical engineering

Research History (researchmap)

  • Nagaoka University of Technology   Professor Emeritus

    2025.4

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  • Niigata University   特任教授

    2025.4

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  • Nagaoka University of Technology   Professor

    2006.4 - 2025.3

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  • Nagaoka University of Technology   Associate Professor (as old post name)

    1996.4 - 2006.3

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  • 名古屋大学工学部地圏環境工学専攻   助教授

    1992.4 - 1996.3

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  • Nagoya University   School of Engineering   Associate Professor (as old post name)

    1990.4 - 1992.3

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  • Nagoya University   School of Engineering   Research Assistant

    1987.4 - 1990.3

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Research History

  • Niigata University   Institute of Science and Technology, Academic Assembly   Specially Appointed Professor

    2025.4

  • Niigata University   Faculty of Engineering   Specially Appointed Professor

    2025.4

  • Nagaoka University of Technology   Professor Emeritus

    2025.4

  • Nagaoka University of Technology   Professor

    2006.4 - 2025.3

  • Nagaoka University of Technology   Associate Professor (as old post name)

    1996.4 - 2006.3

  • Nagoya University   Associate Professor (as old post name)

    1990.4 - 1996.3

  • Nagoya University   Research Assistant

    1987.4 - 1990.3

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Committee Memberships

  • Editorial Board of Soils and Foundations,JGS   Associate Editors  

    2021.6 - 2024.5   

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  • 土木学会   論文集編集委員会C分冊編集小委員会委員長  

    2018.5 - 2020.4   

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  •   地盤工学会北陸支部・支部長  

    2016.5 - 2020.4   

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    Committee type:Other

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  •   地盤工学会・理事  

    2009.5 - 2011.5   

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  •   日本応用地質学会北陸支部・支部長  

    2008.5 - 2025.4   

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    Committee type:Other

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  •   Exective board member of Soils & Foundations  

    2012.5 - 2015.4   

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    Committee type:Other

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  •   日本応用地質学会・代議員  

    2008.5   

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  •   地盤工学会北陸支部・副支部長  

    2008.5 - 2016.4   

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Papers

  • Undrained Failure Envelope (V–H–M) of Rigid Strip Footings on Clayey Soil Slopes under Eccentric and Inclined Loads Reviewed

    Pham N. Quang, Ohtsuka Satoru, Isobe Koichi, Pham N. Vinh, Hoang P. Hoa

    Arabian Journal for Science and Engineering   2025.6

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    Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    DOI: 10.1007/s13369-025-10304-9

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    Other Link: https://link.springer.com/article/10.1007/s13369-025-10304-9/fulltext.html

  • Study on long-term subsidence of soft clay due to Niigata-ken Chuetsu-oki earthquake of 2007 Reviewed

    Jiang, Y., Isobe, K., Ohtsuka, S., Takahara, T.

    Soils and Foundations   65 ( 1 )   101536 - 101536   2025.2

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.sandf.2024.101536

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  • Sensitivity analysis on long-term subsidence of soft clay due to The Niigataken Chuetsu-oki Earthquake in 2007 Reviewed

    Yazhou Jiang, Koichi Isobe, Satoru Ohtsuka, Toshiyuki Takahara

    Japanese Geotechnical Society Special Publication   10 ( 44 )   1635 - 1640   2024.10

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:The Japanese Geotechnical Society  

    DOI: 10.3208/jgssp.v10.os-33-01

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  • Simulation of the ultimate bearing capacity of a spread foundation on sandy soils: rigid plastic FEM approach with inclined load and size effect incorporating stress-dependent non-linear yield function Reviewed

    Kazuhiro Kaneda, Masamichi Aoki, Satoru Ohtsuka

    Japanese Geotechnical Society Special Publication   10 ( 29 )   1116 - 1120   2024.10

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:The Japanese Geotechnical Society  

    DOI: 10.3208/jgssp.v10.os-18-08

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  • AI-Based Slope Hazard Analysis of 2011 Niigata-Fukushima Heavy Rainfall Disaster in Japan Invited

    Rin Kobayashi, Satoru Ohtsuka, Shigeaki Oka, Shunichi Onitsuka, Naoaki Kawamura

    Lecture Notes in Civil Engineering, Springer   1 ( 1 )   3 - 14   2024.5

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    Authorship:Corresponding author   Language:English   Publishing type:Part of collection (book)   Publisher:Springer Nature Singapore  

    DOI: 10.1007/978-981-99-9223-2_1

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  • 新潟県の地下水利用と地盤沈下対策 Invited

    大塚 悟

    水環境学会誌   47(A) ( 2 )   57 - 60   2024.3

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    Authorship:Corresponding author   Language:Japanese   Publishing type:Research paper (scientific journal)  

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  • Limit load space of rigid strip footing on sand slope subjected to combined eccentric and inclined loading Reviewed

    Quang N. Pham, Satoru Ohtsuka, Koichi Isobe, Vinh N. Pham, Hoa P. Hoang

    Computers and Geotechnics   162   105652 - 105652   2023.10

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.compgeo.2023.105652

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  • Examination of the ultimate bearing capacity formula regarding size effect and relative density for sandy soils Reviewed

    Tahir Iqbal, Satoru Ohtsuka, Koichi Isobe, Yutaka Fukumoto

    17th Asian Regional Geotechnical Engineering Conference, ISSMGE   1 ( 1 )   1318 - 1322   2023.8

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    Language:English  

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  • Modified ultimate bearing capacity formula of strip footing on sandy soils considering strength non-linearity depending on stress level Reviewed

    Tahir Iqbal, Satoru Ohtsuka, Koichi Isobe, Yutaka Fukumoto, Kazuhiro Kaneda

    Soils and Foundations   63 ( 3 )   1 - 15   2023.6

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    Language:English   Publishing type:Research paper (scientific journal)  

    File: 1-s2.0-S0038080623000549-main.pdf

    DOI: 10.1016/j.sandf.2023.101325

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  • Influence of strip footing size on the ultimate bearing capacity formula for sandy soils Reviewed

    Tahir Iqbal, Satoru Ohtsuka, Koichi Isobe, Yutaka Fukumoto, Kazuhiro Kaneda

    International Journal of GEOMATE   24 ( 102 )   1 - 9   2023.1

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.21660/2023.102.g12171

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  • Limit load space of rigid strip footing on cohesive-frictional soil subjected to eccentrically inclined loads Reviewed

    Quang N. Pham, Satoru Ohtsuka, Koichi Isobe, Yutaka Fukumoto

    Computers and Geotechnics   151   104956 - 104956   2022.11

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.compgeo.2022.104956

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  • End bearing capacity of a single incompletely end-supported pile based on the rigid plastic finite element method with non-linear strength property against confining stress Reviewed

    Hamidou Hamadoum Tamboura, Koichi Isobe, Satoru Ohtsuka

    Soils and Foundations   62 ( 4 )   101182 - 101182   2022.8

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.sandf.2022.101182

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  • A coupled particle-fluid numerical analysis of failure initiation of non-cohesive granular soils induced by upward seepage flow Reviewed

    Yutaka Fukumoto, Satoru Ohtsuka

    20th International Conference on Soil Mechanics and Geotechnical Engineering   1 ( 1 )   2493(TC103)   2022.5

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  • Numerical Investigation on Bearing Capacity of Rigid Footing on Sandy Soils Under Eccentrically Inclined Load Reviewed

    N. Quang Pham, Satoru Ohtsuka

    Lecture Notes in Civil Engineering   333 - 341   2022

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    Publishing type:Part of collection (book)   Publisher:Springer Singapore  

    DOI: 10.1007/978-981-16-7735-9_37

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  • Wide-area Land Subsidence of Kashiwazaki Plain due to the 2007 Niigata-ken Chuetsu-Oki Earthquake Reviewed

    S. Ohtsuka, K. Isobe, Y. Fukumoto

    Geotechnical Engineering   52 ( 4 )   1 - 7   2021.12

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

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  • Levee damage and revetment erosion by the 2019 Typhoon Hagibis in the Chikuma River, Japan Reviewed

    Satoru Ohtsuka, Yutaka Sato, Takahiro Yoshikawa, Toshio Sugii, Takeshi Kodaka, Kenichi Maeda

    Soils and Foundations, JGS   61 ( 4 )   1172 - 1188   2021.8

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.sandf.2021.05.009

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  • 2-D coupled fluid-particle numerical analysis of seepage failure of saturated granular soils around an embedded sheet pile with no macroscopic assumptions Reviewed

    Yutaka Fukumoto, Hongxuan Yang, Tokuzo Hosoyamada, Satoru Ohtsuka

    Computers and Geotechnics   136   104234 - 104234   2021.8

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.compgeo.2021.104234

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  • Ultimate Bearing Capacity of Rigid Footing on Two-Layered Soils of Sand–Clay Reviewed

    Quang N. Pham, Satoru Ohtsuka

    International Journal of Geomechanics, ASCE   21 ( 7 )   04021115-1 - 15   2021.7

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Society of Civil Engineers (ASCE)  

    DOI: 10.1061/(asce)gm.1943-5622.0002095

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  • ON THE SIMILARITY OF A HYDRAULIC MODEL EXPERIMENT FOR A RIVER INCLUDING SEEPAGE FLOW THROUGH SATURATED POROUS RIVERBED MATERIALS Reviewed

    Hongxuan YANG, Yutaka FUKUMOTO, Tokuzo HOSOYAMADA, Satoru OHTSUKA

    Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM))   76 ( 2 )   I_411 - I_422   2020.12

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Japan Society of Civil Engineers  

    DOI: 10.2208/jscejam.76.2_i_411

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  • Limit load space of rigid footing under eccentrically inclined load Reviewed

    Quang N. Pham, Satoru Ohtsuka, Koichi Isobe, Yutaka Fukumoto

    Soils and Foundations   60 ( 4 )   811 - 824   2020.8

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.sandf.2020.05.004

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  • Consideration on Wide Area Land Subsidence of the Muikamachi Basin by Groundwater Use in Winter Reviewed

    Satoru OHTSUKA, Atsushi URABE, Hiroshi KURITA

    Journal of the Japan Society of Engineering Geology   61 ( 2 )   38 - 49   2020.6

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Japan Society of Engineering Geology  

    DOI: 10.5110/jjseg.61.38

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  • 浸透流と河川流の同時計算に基づく流体力による護床工ブロックの安定性評価 Reviewed

    楊宏選, 山本陽子, 福元豊, 細山田得三, 大塚悟, 福島雅紀

    河川技術論文集   26 ( 1 )   451 - 456   2020.6

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  • ON THE FLOW FIELD AND STRUCTURAL STABILITY FOR CONSOLIDATION WORKS WITH A HYDRAULIC DROP Reviewed

    Hongxuan YANG, Yutaka FUKUMOTO, Tokuzo HOSOYAMADA, Satoru OHTSUKA

    Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM))   75 ( 2 )   I_519 - I_530   2019.12

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Japan Society of Civil Engineers  

    DOI: 10.2208/jscejam.75.2_i_519

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  • Ultimate bearing capacity of rigid footing under eccentric vertical load Reviewed International journal

    Quang N. Pham, Satoru Ohtsuka, Koichi Isobe, Yutaka Fukumoto, Takashi Hoshina

    Soils and Foundations   59 ( 6 )   1980 - 1991   2019.12

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Japanese Geotechnical Society  

    DOI: 10.1016/j.sandf.2019.09.004

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  • 二次元固定床模型実験及びそれを再現する数値解析モデルによる床止め工の圧力と流速等の考察 Reviewed

    楊宏選, 福元豊, 細山田得三, 大塚悟

    河川技術論文集   25 ( 1 )   451 - 456   2019.6

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    Language:Japanese   Publishing type:Research paper (international conference proceedings)   Publisher:土木学会  

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  • Group effect on ultimate lateral resistance of piles against uniform ground movement Reviewed

    Quang N.Pham, Satoru Ohtsuka, Koichi Isobe, Yutaka Fukumoto

    Soils and Foundations   59 ( 1 )   27 - 40   2019.3

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:Japanese Geotechnical Society  

    DOI: 10.1016/j.sandf.2018.08.013

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  • Assessing the ultimate bearing capacity of footing in two-layered clayey soil system using the rigid plastic finite element method Reviewed

    Kazuhiro Kaneda, Masamichi Aoki, Satoru Ohtsuka

    International Journal on Geotechnique, Construction Materials and Environment   17 ( 60 )   144 - 150   2019.3

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:GEOMATE  

    DOI: 10.21660/2019.60.8259

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  • Ultimate vertical bearing capacity of clayey squeeze breakdown using rigid-plastic finite element method Reviewed

    Kazuhiro Kaneda, Masamichi Aoki, Tomohiro Tanikawa, Satoru Ohtsuka

    International Journal on Geotechnique, Construction Materials and Environment   17 ( 60 )   76 - 82   2019.3

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  • Discrete particle simulation model for slaking of geomaterials including swelling clay minerals Reviewed

    Yutaka Fukumoto, Satoru Ohtsuka

    International Journal on Geotechnique, Construction Materials and Environment   16 ( 54 )   134 - 139   2019.2

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    DOI: 10.21660/2019.54.8230

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  • 水・地盤連成解析手法による落差工周辺の河床構造物の安定性評価 Reviewed

    楊宏選, 福元豊, 細山田得三, 大塚悟

    土木学会論文集B1(水工学)   74 ( 5 )   I_655 - I_660   2018.11

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  • Identification of shear strength and seismic coefficient by back analyzing surficial slides in the 2004 Mid-Niigata prefecture earthquake Reviewed

    Surangani Bandara, Satoru Ohtsuka, Yutaka Fukumoto

    Landslides   15 ( 11 )   1 - 12   2018.6

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Springer Verlag  

    DOI: 10.1007/s10346-018-1029-6

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  • 落差工による跳水・浸透流およびそれらの河床構造物の安定性に及ぼす影響 Reviewed

    楊宏選, 福元豊, 細山田得三, 大塚悟

    河川技術論文集   24 ( 1 )   655 - 660   2018.6

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    Language:Japanese   Publishing type:Research paper (international conference proceedings)   Publisher:土木学会  

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  • 落差工による跳水・浸透流およびそれらの河床構造物の安定性に及ぼす影響

    楊宏選, 福元豊, 細山田得三, 大塚悟

    土木学会論文集B1(水工学)   75   - - -   2018

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    Publisher:土木学会  

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  • 3-D direct numerical model for failure of non-cohesive granular soils with upward seepage flow Reviewed

    Yutaka Fukumoto, Satoru Ohtsuka

    Computational Particle Mechanics   1 ( 999 )   1 - 12   2017.12

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Springer International Publishing  

    DOI: 10.1007/s40571-017-0180-5

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  • 擁壁の地震時主働土圧に関する解析的考察 Reviewed

    水野和憲, 前田宗春, 大塚悟, 小林俊一

    土木学会論文集A2(応用力学)   73 ( 2 )   I_313 - I_320   2017.12

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  • Spatial distribution of landslides induced by the 2004 Mid-Niigata prefecture earthquake, Japan Reviewed

    Surangani Bandara, Satoru Ohtsuka

    LANDSLIDES   14 ( 6 )   1877 - 1886   2017.12

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1007/s10346-017-0819-6

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  • Comparison of sheared granular soils: Same void ratio but considerably different fabric Reviewed

    Yutaka Fukumoto, Satoru Ohtsuka

    Geotechnical Engineering Journal of the SEAGS & AGSSEA   48 ( 4 )   32 - 39   2017.11

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  • 地すべりの誘因・滑動履歴を考慮した粘性土の応力制御試験と強度定数の考察 Reviewed

    大塚 悟

    土木学会論文集C(地圏工学)   73 ( 1 )   106 - 115   2017.3

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  • 浸透流と土粒子の直接数値計算のためのPS-MRT Lattice Boltzmannモデル Reviewed

    福元 豊, 大塚 悟

    土木学会論文集A2(応用力学)   72 ( 2 )   I_335 - I_343   2016.12

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  • 砂質地盤の寸法効果と傾斜荷重の影響に関する剛塑性有限要素解析 Reviewed

    金田一広, 青木雅路, 大塚悟

    日本建築学会構造系論文集   81 ( 728 )   1665 - 1671   2016.10

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  • Rigid plastic fem analysis considering inclined load and size effects on ultimate bearing capacity of spread foundation on sandy soils Reviewed

    Kazuhiro Kaneda, Masamichi Aoki, Satoru Ohtsuka

    Journal of Structural and Construction Engineering   81 ( 728 )   1665 - 1671   2016.10

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Architectural Institute of Japan  

    DOI: 10.3130/aijs.81.1665

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  • 信濃川大河津分水旧可動堰の基礎構造と空洞発生原因の調査 Reviewed

    大塚悟, 高原利幸, 保坂吉則, 礒部公一

    土木学会論文集C(地圏工学)   72 ( 2 )   86 - 100   2016.6

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  • Prediction of spatial distribution on soil surveying values using geostatics methods Reviewed

    Shinya Inazumi, Kohei Urakami, Satoru Ohtsuka, Osamu Saeki, Ken-ichi Shishido

    Int. J. of Geotechnique, Construction Materials and Environment   10 ( 2 )   1828 - 1833   2016.6

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:The Geomate International Society  

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  • DISCUSSION ON ULTIMATE LATERAL RESISTANCE OF PILE IN CLAYEY GROUND DURING EARTHQUAKE Reviewed

    KOMURA Seichi, SHIRATORI Yohei, OHTSUKA Satoru, HOSHINA Takashi

    Journal of Japan Society of Civil Engineers, Ser. C (Geosphere Engineering)   72 ( 2 )   48 - 61   2016.6

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    Language:Japanese   Publishing type:Research paper (international conference proceedings)   Publisher:Japan Society of Civil Engineers  

    Pile foundation has been designed against the lateral load acting on the superstructure which is induced by the seismic coefficient method. After the Great Hanshin Earthquake, the response displacement method has been employed to assess the reaction force acting on pile. However, this method overestimates the interaction force from the viewpoint of practical design. Various specifications recommend to use the bilinear model on reaction force by considering that the ground goes through the pile. This paper evaluates the ultimate resistance of ground against lateral movement of pile by both model test and rigid plastic finite element analysis. The validity of obtained results is examined through the comparison of both results. The followings are obtained in this study. (1) Ultimate lateral resistance of pile was obtained as 12~13c for clayey ground where c is an undrained shear strength of clay. It was examined by model tests and numerical analyses. The failure area of ground reached to 2.5~3D from the pile center, where D denotes the diameter of pile foundation. (2) Effect of friction cut between pile and ground was investigated. Ultimate lateral resistance of pile was obtained as 9c which is almost same with Brom's formula. Besides, the effect of strength reduction in surrounding ground due to pile installation was parametrically investigated. (3) Ultimate lateral resistance of group piles was obtained as 11c in case of the pile center spacing of 3D. It matched with that of single pile in case of 5D. (4) The current specifications were shown to provide the smaller estimation on ultimate lateral resistance of pile in case of depth that is deeper than effective length on pile (1/β), where the ground deforms through the pile by earthquake vibration. It reveals the specifications may prescribe the dangerous side evaluation in design.

    DOI: 10.2208/jscejge.72.48

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  • Discussion on size effect of footing in ultimate bearing capacity of sandy soil using rigid plastic finite element method Reviewed

    Du L. Nguyen, Satoru Ohtsuka, Takashi Hoshina, Koichi Isobe

    Soils and Foundations   56 ( 1 )   93 - 103   2016.3

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:Japanese Society of Soil Mechanics and Geotechnical Engineering  

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  • Undrained Bearing Capacity of Strip Footings on Clayey Soil subjected to Eccentrically Inclined Load Reviewed

    Quang Ngoc Pham, Satoru Ohtsuka, Binh Ngoc Pham

    5th International Conference on Geotechnics for Sustainable Infrastructure Development, Geotec-Hanoi   2023.12

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  • AI based slope hazard analysis of 2011 Niigata-Fukushima heavy rainfall disaster in Japan Reviewed

    Rin Kobayashi, Satoru Ohtsuka, Shigeaki Oka, Shunichi Onitsuka, Naoaki Kawamura

    2nd International Conference on Construction Resources for Environmentally Sustainable Technologies   1 ( 1 )   1 - 4   2023.11

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  • Ultimate bearing capacity of rigid strip footings on c-ϕ soil subjected to combined eccentric and inclined loading

    Ngoc Quang Pham, Satoru Ohtsuka, Koichi Isobe, Phuong Hoa Hoang

    IOP Conference Series: Materials Science and Engineering   1289 ( 1 )   012088 - 012088   2023.8

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    Publishing type:Research paper (scientific journal)   Publisher:IOP Publishing  

    Abstract

    The present study calculated the maximum bearing capacity of a strip footing against eccentrically inclined coupled loading on c-ϕ soil, by means of the plane strain rigid plastic finite element method (RPFEM). The influence of soil strengths and footing width on the V-H and H-M failure envelopes (presenting the vertical load V, horizontal load H, and moment M) was thoroughly surveyed to assess the uniqueness of the V-H-M failure envelope. Based on the obtained results, the V-H-M failure envelope was found to be distinct for each value of normalized cohesion c/γB and internal friction angle ϕ. A novel equation, which is a function of c/γB and ϕ, was achieved to predict the failure envelope of the V-H-M limit load space.

    DOI: 10.1088/1757-899x/1289/1/012088

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    Other Link: https://iopscience.iop.org/article/10.1088/1757-899X/1289/1/012088/pdf

  • Characteristics of Landslides Induced by the 2004 Mid-Niigata Prefecture Earthquake in Japan Reviewed

    Surangani Bandara, Satoru Ohtsuka

    3rd International Conference on Geotechnical Engineering, ICGE Colombo 2020   1 ( 1 )   443 - 447   2021.12

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  • 3-D direct numerical simulation of seepage flow in a soil matrix: Comparison with a model experiment using the method of RIMS Reviewed

    Yutaka Fukumoto, Satoru Ohtsuka

    3rd International Conference on Geotechnical Engineering, ICGE Colombo 2020   1 ( 1 )   489 - 492   2021.12

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  • Numerical Investigation on Bearing Capacity of Rigid Footing on Sandy Soils Under Eccentrically Inclined Load Reviewed

    Pham Ngoc Quang & Satoru Ohtsuka

    2nd Vietnam Symposium on Advances in Offshore Engineering, VSSMGE   1 ( 1 )   333 - 341   2021.11

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  • Size effect of footing in ultimate bearing capacity of intermediate soil Reviewed

    Tahir Iqbal, Satoru Ohtsuka, Koichi Isobe, Yutaka Fukumoto

    The Second International Conference on Press-in Engineering, International Press-in Association   37 - 45   2021.6

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  • 不連続性岩盤を模擬した金属六角棒積層斜面の地震時挙動評価(8)-剛塑性有限要素法による評価-

    河村精一, 水野和憲, 大塚悟

    第15回岩の国内シンポジウム,土木学会   405 - 410   2021.1

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  • 3-D Particle Simulation Model for Weathering Processes of Geomaterials Under a Wet-Dry Cyclic Condition Reviewed

    Y. Fukumoto, S. Ohtsuka

    Challenges and Innovations in Geomechanics   624 - 631   2021

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    DOI: 10.1007/978-3-030-64514-4_64

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  • Consideration on Limit Load Space of Footing on Various Soils Under Eccentric Vertical Load Reviewed

    Pham N. Quang, Ohtsuka Satoru, Isobe Koichi, Fukumoto Yutaka

    Challenges and Innovations in Geomechanics   75 - 84   2021

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    DOI: 10.1007/978-3-030-64518-2_10

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  • 2-D direct numerical analyses of sand boils around obstacles with various shapes by using a coupled LB-DE model Reviewed

    Yutaka Fukumoto, Tokuzo Hosoyamada, Yang Hongxuan, Satoru Ohtsuka

    Third International Conference on Computational Engineering and Science for Safety and Environmental Problems   1 ( 1 )   MS08-2-01 - MS08-2-01   2020.12

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  • グラベル・パイルによる砂質地盤の締固め効果に関する模型試験 Reviewed

    中島啓太, 大塚悟, 福元豊

    第14回地盤改良シンポジウム論文集   1 ( 1 )   127 - 132   2020.12

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  • Effect of Freeze-Thaw Cycles on Crushed Mudstone

    Mei Nihonyanagi, Rina Matuda, Nariaki Kodama, Yutaka Fukumoto, Satoru Ohtsuka

    The 5th International Conference on “Science of Technology Innovation” 2020   7 ( 1 )   STI-9-26 - STI-9-26   2020.10

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  • Discussion on efficacy of rigid plastic finite element method for ultimate bearing capacity analysis of intermediate soil using non-linear shear strength model

    Tahir Iqbal, Satoru Ohtsuka, Koichi Isobe, Yutaka Fukumoto

    The 5th International Conference on “Science of Technology Innovation” 2020   7 ( 1 )   STI-9-45 - STI-9-45   2020.10

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  • 千曲川・信濃川全域の被害 Invited

    大塚 悟

    消防防災の科学   141   19 - 25   2020

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  • Ultimate bearing capacity of rigid footing on sandy soils for eccentrically inclined load

    Quang N.Pham, Satoru Ohtsuka, Yutaka Fukumoto

    4th Science of Technology Innovation, STI-Gigaku   2019.11

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  • Improvement in coupled DEM-LBM model for internal erosion of geomaterials with a broad particle size distribution Reviewed

    Yutaka Fukumoto, Satoru Ohtsuka

    16th Asia Regional Conference on Soil Mechanics and Geotechnical Engineering   JGS-007   1 - 4   2019.10

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  • Stability analysis of caisson type seawall against tsunami in comparison with model tests Reviewed

    Satoru Ohtsuka, Yutaka Fukumoto: Hiroyuki Yamazaki and Kazuhiro Kaneda

    16th Asia Regional Conference on Soil Mechanics and Geotechnical Engineering   JGS-044   1 - 4   2019.10

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  • 落差床止め工の流れ場および安定性について

    楊宏選, 福元豊, 細山田得三, 大塚 悟

    第22回応用力学シンポジム   1 ( 1 )   149 - 150   2019.6

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  • 基礎の寸法効果を考慮した地盤支持力式の適用性に関する検討

    大塚 悟, Huynh Anh Dung, Pham Ngoc Quang

    第22回応用力学シンポジム   1 ( 1 )   353 - 354   2019.6

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  • Analysis for wide-area land subsidence of Kashiwazaki Plain due to the 2007 Niigata-ken Chuetsu-Oki earthquake

    Satoru Ohtsuka, Koichi Isobe, Yutaka Fukumoto

    7th International Conference on Earthquake Geotechnical Engineering   1 ( 1 )   4195 - 4201   2019.6

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  • Effect of Ground Movement Direction on Ultimate Lateral Resistance of Line Alignment Piles in Clay Reviewed

    Quang N. Pham, Satoru Ohtsuka, Koichi Isobe, Yutaka Fukumoto

    Transactions on GIGAKU   6 ( 1 )   06003/1 - 06003/8   2019.6

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  • EFFECT OF THE UNIFORMITY COEFFICIENT AND PLASTICITY ON CORRELATION BETWEEN THE N-VALUE AND LIQUEFACTION STRENGTH OF MIXED SANDY SOIL

    KUDAI Kenta, SASSA Shinji, GOTO Shoya, HANAZAWA Daisuke, OHTSUKA Satoru

    Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering)   75 ( 2 )   I_241 - I_246   2019

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    Liquefaction prediction is based on liquefaction strength presumed from the N-value. In the case of soil with fine contents, the N-value is revised depending on the content rate(Fc) and the plasticity index(Ip). But the impact of the sand’s uniformity coefficient and fine content’s plasticity against accuracy of liquefaction prediction is not adequately investigated. Based on the above, this research experimentally studied the effect of the sand’s uniformity coefficient and fine content’s plasticity on the correlation between the N-value and liquefaction strength of mixed sandy soil. This research showed the possibility for the risk of liquefaction being underestimated in case where the sand’s uniformity coefficient is low while it tends to be assessed on the safe side if the sand’s uniformity coefficient is high.

    DOI: 10.2208/jscejoe.75.i_241

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    Other Link: http://id.ndl.go.jp/bib/031264519

  • 河川を横断する落差工周囲の河川流と浸透流の相互作用

    細山田得三, 楊宏選, 福元豊, 大塚悟

    第6回河川堤防技術シンポジウム   1 ( 1 )   49 - 52   2018.12

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  • Assessing the ultimate bearing capacity of footing in two-layered clayey soil system using the rigid plastic finite element method Reviewed

    Kazuhiro Kaneda, Masamichi Aoki, Satoru Ohtsuka

    Proc. of 8th International Conference on Geotechnique, Construction Materials and Environment   1 ( 1 )   335 - 340   2018.11

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  • Discrete particle simulation model for slaking of geomaterials including swelling clay minerals Reviewed

    Yutaka Fukumoto, Satoru Ohtsuka

    Proc. of 8th International Conference on Geotechnique, Construction Materials and Environment   999 ( 999 )   999 - 999   2018.11

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  • Coupled particle-fluid numerical simulation model for internal erosion of granular soils with a broad particle size distribution Reviewed

    Yutaka Fukumoto, Satoru Ohtsuka

    Proc. of 9th International Conference on Scour and Erosion   9 ( 1 )   639 - 644   2018.11

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  • Ultimate lateral resistance of piles group in clayey soils against various directions of ground movement Reviewed

    Quang N.Pham, Satoru Ohtsuka, Koichi Isobe, Yutaka Fukumoto

    The first Vietnam Symposium on Advances in Offshore Engineering   1 ( 1 )   408 - 411   2018.11

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    DOI: 10.1007/978-981-13-2306-5_57

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  • Examination of caisson-type quay wall for resilient structure by using 1G shaking table test Reviewed

    Kazuhiro Kaneda, Hiroyuki Yamazaki, Satoru Ohtsuka

    The first Vietnam Symposium on Advances in Offshore Engineering   1 ( 1 )   151 - 157   2018.11

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    DOI: 10.1007/978-981-13-2306-5_19

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  • Effect of ground movement direction on ultimate lateral resistance of line alignment piles in clay

    Quang N.Pham, Satoru Ohtsuka, Yutaka Fukumoto

    7th Gigaku2018   RD ( 057 )   1 - 1   2018.10

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  • Simulation of Rockfall Trajectories and Validation of Countermeasure Design Using Distinct Element Method Reviewed

    Chunxiang Wang, Katsumi Itoh, Satoru Ohtsuka

    INTERPRAEVENT International Symposium 2018 in the Pacific Rim   1 ( P1-16 )   1 - 2   2018.10

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  • Study of vertical bearing capacity of spread foundation using rigid plastic finite element method Reviewed

    Kazuhiro Kaneda, Masamichi Aoki, Satoru Ohtsuka

    International Seminar on Numerical Analysis in Geotechnics 2018   1 ( AP15 )   1 - 8   2018.3

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  • LABORATORY TESTS ON LIQUEFACTION RESISTANCE AND N-VALUE OF SAND WITH FINE CONTENTS WITH VARYING PLASTICLITY

    KOBAYASHI Takaaki, SASSA Shinji, GOTO Shoya, FUKUI Akihiro, OHTSUKA Satoru

    Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering)   74 ( 2 )   I_838 - I_843   2018

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    The liquefaction resistance and N-value of silty/clayey sand with varying fine content and plasticity were investigated by laboratory testing. The liquefaction resistance of silty/clayey-sands decreased with the increment of fine content as opposed to the assumption of the current liquefaction assessment method. Meanwhile, the N-values of the silty/clayey-sands decreased with the fine contents. It was found that the current liquefaction assessment method overestimates the liquefaction resistance of the materials used in this study.

    DOI: 10.2208/jscejoe.74.i_838

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  • Group effect on ultimate lateral resistance of piles in clayey soils against horizontal ground movement Reviewed

    Quang N.Pham, Satoru Ohtsuka, Koichi Isobe, Yutaka Fukumoto

    15th International Conference of the Internal Association for Computer Methods and Advances in Geomechanics,   1 ( 630 )   1 - 8   2017.10

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  • An effective direct numerical simulation model of granular soils and seepage flow by using DEM and LBM Reviewed

    Yutaka Fukumoto, Satoru Ohtsuka

    15th International Conference of the Internal Association for Computer Methods and Advances in Geomechanics,   1 ( 999 )   1 - 8   2017.10

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  • Numerical simulations with cushioning material installed behind the retaining wall for resilient structures Reviewed

    Kazuhiro Kaneda, Hiroyuki Yamazaki, Satoru Ohtsuka

    COMPDYN 2017 - Proceedings of the 6th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering   2 ( 18382 )   3671 - 3681   2017

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    DOI: 10.7712/120117.5674.18382

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  • 新潟地方における特色ある地域地盤の特性例と調査・設計・施工上の問題点

    大塚悟, 金子俊哉, 高橋浩之, 西達也

    基礎工   44 ( 11 )   30 - 35   2016.11

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  • Ultimate bearing capacity of footing on sandy soils against combined load of vertical, horizontal and moment loads Reviewed

    Du L. Nguyen, Satoru Ohtsuka, Kazuhiro Kaneda

    Int. J. of Geotechnique, Construction Materials and Environment   10 ( 1 )   1649 - 1655   2016.3

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  • Shaking table test on cavity formation below Ohkozu old movable weir in the Shinano River

    Koichi Isobe, Satoru Ohtsuka

    Proc. of 6th International Conference on Earthquake Geotechnical Engineering   1 ( 1 )   147-1 - 147-9   2015.11

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  • 東北地方太平洋沖地震における火山灰質盛土被害の分析 Reviewed

    大塚 悟, 小石悠介, 磯部 公一, 遠藤真哉

    地盤工学ジャーナル   10 ( 3 )   381 - 390   2015.9

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  • Study on volcanic sediment embankment collapse in the 2011 off the Pacific Coast of Tohoku Earthquake

    Satoru Ohtsuka, Koichi Isobe, Yusuke Koishi, Shinya Endo

    Volcanic Rocks and Soils   1 ( 1 )   189 - 190   2015.6

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  • Life cycle assessment on recycling of construction sludges in geotechnical engineering fields Reviewed

    Shinya Inazumi, Cheema Soralump, Suttisak Soralump, Satoru Ohtsuka, Yoshihiro Nakagishi

    Int. J. of Geotechnique, Construction Materials and Environment   9 ( 2 )   1553 - 1566   2015.3

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  • PS-MRT LATTICE BOLTZMANN MODEL FOR DIRECT SIMULATION OF GRANULAR SOILS AND SEEPAGE FLOW

    Y. Fukumoto, S. Ohtsuka, A. Murakami

    PARTICLE-BASED METHODS IV-FUNDAMENTALS AND APPLICATIONS   1 ( 1 )   537 - 544   2015

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  • Spatial distribution of landslides triggered by the 2004 Mid Niigata prefecture earthquake in Japan Reviewed

    K. M. S. Bandara, S. Ohtsuka

    Computer Methods and Recent Advances in Geomechanics   1 ( 1 )   1903 - 1906   2015

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  • Estimation of ultimate lateral resistance of pile in clayey ground Reviewed

    S. Koumura, Y. Shiratori, S. Ohtsuka, T. Hoshina

    Computer Methods and Recent Advances in Geomechanics   1 ( 1 )   947 - 950   2015

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  • In-situ loading test of wooden pile at Shinano River Ohkouzu old movable weir and discussion on foundation design Reviewed

    Satoru Ohtsuka, Toshiyuki Takahara, Yoshinori Hosaka, Koichi Isobe

    15th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2015: New Innovations and Sustainability   1 ( 1 )   1456 - 1459   2015

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    DOI: 10.3208/jgssp.JPN-091

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  • Research on cavity formation below Ohkozu old movable weir in the Shinano River Reviewed

    K. Isobe, S. Ohtsuka

    15th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2015: New Innovations and Sustainability   1 ( 1 )   1452 - 1455   2015

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    DOI: 10.3208/jgssp.JPN-021

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  • Development and its validation of Rigid Plastic Moving Particle Simulation method Reviewed

    K. Isobe, S. Ohtsuka, T. Hoshina

    Computer Methods and Recent Advances in Geomechanics   1 ( 1 )   165 - 168   2015

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  • Analysis of geological and geomorphological characteristics of landslides triggered by 2004 Chuetsu earthquake in Japan Reviewed

    Surangani BANDARA, Satoru OHTSUKA, Tsukasa IWABE, Yasuyuki MIYAKI, Koichi ISOBE

    INTERPRAEVENT International Symposium 2014.   1 ( 1 )   1 - 4   2014.11

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  • 浸透場におけるケーソン基礎の極限支持力解析 Reviewed

    保科隆, 大塚悟, 磯部公一, 瀧本英朗, 田中達也

    土木学会論文集 A2(応用力学)   70 ( 2 )   155 - 164   2014.11

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  • 大河津分水旧可動堰を支えた木杭の支持力特性

    大塚悟, 高原利幸, 保坂吉則, 中野義仁

    土木史跡の地盤工学的分析・評価に関するシンポジウム   1 ( 1 )   1 - 4   2014.10

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  • Development of Moving Particle Simulation method using a rigid plastic constitutive model

    Koichi Isobe, Satoru Ohtsuka, Takashi Hoshina

    IS-Cambridge   1 ( 1 )   1 - 4   2014.9

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  • Inverse analysis of surface slope failures caused by 2004 Mid-Niigata prefecture earthquake

    Surangi Bandara, Satoru Ohtsuka

    International Workshop on Geotechnology for natural Disasters-6th Japan-Taiwan Joint Workshop on Geotechnical Hazards from Large earthquakes and Heavy Rainfalls   1 ( 1 )   19 - 20   2014.7

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  • Seismic Landslide Hazard Assessment and Evaluation of Factors Controlling Landslides In 2004 Chuetsu Earthquake

    Surangi Bandara, Satoru Ohtsuka

    The 3rd International GIGAKU Conference in Nagaoka, SO-1, P.90   1 ( 1 )   90 - 90   2014.6

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  • Field investigation and model tests on differential settlement of houses due to liquefaction in the Niigata-ken Chuetsu-Oki Earthquake of 2007 Reviewed

    Koichi Isobe, Satoru Ohtsuka, Hirokazu Nunokawa

    Soils and Foundations   54 ( 4 )   675 - 686   2014.6

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  • 地震後も続く粘性土地盤の長期圧密沈下挙動の解明

    礒部公一, 大塚悟, 高原利幸

    地盤工学会特別シンポジウム−東日本大震災を乗り越えて−発表論文集   1 ( 1 )   205 - 211   2014.5

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  • 剛塑性有限要素法による防潮堤基礎構造の支持力検討

    金田一広, 東中邦夫, 大塚悟

    地盤工学会特別シンポジウム−東日本大震災を乗り越えて−発表論文集   1 ( 1 )   685 - 690   2014.5

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  • Characteristics of the Wooden Piles' Bearing Capacity at Ohkozu Old Movable Weir Reviewed

    Ohtsuka Satoru, Takahara Toshiyuki, Hosaka Yoshinori

    62 ( 4 )   34 - 37   2014.4

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    Other Link: http://dl.ndl.go.jp/info:ndljp/pid/10422277

  • Design approach to a method for reinforcing existing caisson foundations using steel pipe sheet piles Reviewed

    Koichi Isobe, Makoto Kimura, Satoru Ohtsuka

    Soils and Foundations   54 ( 2 )   141 - 154   2014

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    DOI: 10.1016/j.sandf.2014.02.006

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  • Ultimate bearing capacity analysis of ground against inclined load by taking account of nonlinear property of shear strength Reviewed

    Du, N. L, Ohtsuka, S, Hoshina, T, Isobe, K, K. Kaneda

    Int. J. of Geotechnique, Construction Materials and Environment   5 ( 2 )   678 - 684   2013.11

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  • Ultimate bearing capacity analysis of ground against inclined load by taking account of nonlinear property of shear strength Reviewed

    Du, N. L, Ohtsuka, S, Hoshina, T, Isobe, K, K. Kaneda

    Third International Conference on Geotechnique, Construction Materials and Environment   0 ( 0 )   1499 - 1502   2013.11

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  • 剛塑性有限要素法を用いた根入れ基礎の支持力解析 Reviewed

    金田一広, 谷川友浩, 濱田純次, 大塚悟, 青木雅路

    日本建築学会技術報告集   19 ( 43 )   875 - 880   2013.10

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  • 剛塑性有限要素法を用いた二層系粘性土地盤の直接基礎の支持力解析 Reviewed

    金田一広, 谷川友浩, 濱田純次, 大塚悟, 青木雅路

    日本建築学会技術報告集   19 ( 43 )   881 - 885   2013.10

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  • Analysis of ultimate bearing capacity of footing of two layered clayey soil system by rigid plastic finite element method Reviewed

    Kazuhiro Kaneda, Tomohiro Tanikawa, Junji Hamada, Satoru Ohtsuka, Masamichi Aoki

    AIJ Journal of Technology and Design   19 ( 43 )   881 - 885   2013.10

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    DOI: 10.3130/aijt.19.881

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  • Bearing capacity analysis of embedded foundation by rigid plastic finite element method Reviewed

    Kazuhiro Kaneda, Tomohiro Tanikawa, Junji Hamada, Satoru Ohtsuka, Masamichi Aoki

    AIJ Journal of Technology and Design   19 ( 43 )   875 - 880   2013.10

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    DOI: 10.3130/aijt.19.875

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  • Study on long-term subsidence of soft clay due to 2007 Niigata Prefecture Chuetsu-Oki Earthquake Reviewed

    Koichi Isobe, Satoru Ohtsuka, Toshiyuki Takahara

    18th International Conference on Soil Mechanics and Geotechnical Engineering   0 ( 0 )   1499 - 1502   2013.9

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  • 剛塑性動的変形解析を用いた地震による土構造物の残留変形量の評価

    保科 隆, 大塚 悟, 磯部公一

    大ひずみ領域を考慮した土の繰返しせん断特性に関するシンポジウム論文集   0 ( 0 )   173 - 180   2013.5

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  • 剛塑性有限要素解析を用いた直接基礎の支持力の検討 Reviewed

    金田一広, 大塚 悟, 重野喜政, 青木雅路, 濱田純次, 谷川友浩

    建築学会論文集   78 ( 686 )   763 - 770   2013.4

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  • Examination on ultimate bearing capacity of footing by regid plastic finite element analysis Reviewed

    Kazuhiro Kaneda, Satoru Ohtsuka, Yoshimasa Shigeno, Masamichi Aoki, Junji Hamada, Tomohiro Tanikawa

    Journal of Structural and Construction Engineering   78 ( 686 )   763 - 770   2013.4

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    DOI: 10.3130/aijs.78.763

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  • STUDY ON LONG-TERM SUBSIDENCE OF SOFT CLAY DUE TO 2007 NIIGATA PREFECTURE CHUETSU-OKI EARTHQUAKE Reviewed

    Koichi Isobe, Satoru Ohtsuka

    PROCEEDINGS OF THE 5TH INTERNATIONAL YOUNG GEOTECHNICAL ENGINEERS' CONFERENCE (IYGEC 2013)   2   510 - 513   2013

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    DOI: 10.3233/978-1-61499-297-4-510

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  • Field investigation and model tests on unequal settlement of houses due to liquefaction in the Niigataken Chuetsu-Oki Earthquake in 2007

    Isobe,K, Ohtsuka, S, H. Nunokawa

    15th World Conference of Earthquake Engineering   1 ( 1 )   191 - 200   2012.9

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  • Development of slice method based residual deformation analysis of earth structure against earthquake

    Hoshina,T, Ohtsuka, S, K. Isobe

    15th World Conference of Earthquake Engineering   1 ( 1 )   191 - 200   2012.9

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  • Applicability of reinforcing method for existing caisson foundation by steel pipe sheet piles

    Isobe, K, Ohtsuka, S, Kimura, M

    IS-KANAZAWA   1 ( 1 )   191 - 200   2012.9

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  • 地盤の拘束圧非線形強度特性を考慮した極限支持力の剛塑性有限要素解析 Reviewed

    保科 隆, 大塚 悟, 磯部公一

    土木学会論文集A2(応用力学)   68 ( 2 )   327 - 336   2012.9

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  • 新潟県中越沖地震の家屋被害特性の分析 Reviewed

    落合弘和, 山田健人, 大塚 悟, 磯部公一

    土木学会論文集A1(構造・地震工学)   68 ( 4 )   1052 - 1061   2012.7

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  • Numerical simulation on long-term subsidence of soft clay due to the 2007 Niigata Prefecture Chuetsu-Oki Earthquake

    Isobe, K, Ohtsuka, S, Takahara, T

    6th International Workshop on New Frontiers in Computational Geotechnics   1 ( 1 )   191 - 200   2012.5

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  • Residual deformation analysis of slope by slice method with rigid plastic constitutive equation for slip line Reviewed

    17 ( 1 )   1 - 1   2012.5

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  • 福島県中通りおよびいわき地域における地盤被害 Reviewed

    中村晋, 仙頭紀明, 梅村順, 大塚 悟, 豊田浩史

    地盤工学ジャーナル   7 ( 1 )   91 - 101   2012.3

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  • 低強度シーム層を有する受け盤斜面のハイブリッド型土水連成安定解析の試み

    保科 隆, 大塚 悟, 磯部公一

    斜面災害における予知と対策技術の最前線に関する国際シンポジウム   1 ( 1 )   179 - 185   2011.11

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  • 新潟県中越沖地震の家屋被害分析

    山田健人, 落合弘和, 大塚 悟, 磯部公一

    第31回地震工学研究発表会   1 ( 1 )   0 - 0   2011.11

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  • 剛塑性動的変形解析法による土構造物の残留変形解析 Reviewed

    保科 隆, 大塚 悟, 磯部公一

    応用力学論文集   14 ( 1 )   251 - 259   2011.9

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  • 剛塑性動的変形解析の土構造物への適用性に関する検討 Reviewed

    保科 隆, 大塚 悟, 磯部公一

    土木学会論文集A2(応用力学)   67 ( 2 )   I_251 - I_259   2011.9

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    DOI: 10.2208/jscejam.67.I_251

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  • 低強度シーム層を内在する自然斜面の斜面安定解析 Reviewed

    保科 隆, 大塚 悟, 磯部公一

    地盤工学ジャーナル   6 ( 2 )   191 - 200   2011.6

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  • Digital Ground Model of Niigata Area in Japan Reviewed

    Yoshinori Hosaka, Satoru Ohtsuka, Yukihiko Kamoi, Koji Ichimura

    Proc. of 14th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering   1 ( 1 )   0 - 0   2011.5

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  • Lateral resistance of inclined pile bearing integrated column by steel pipes Reviewed

    K. Isobe, S. Ohtsuka, K. Akiyama

    Proc. of 14th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering   1 ( 1 )   0 - 0   2011.5

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  • Numerical simulation on seismic performance of steel pipe pile foundation using inclined pile Reviewed

    K. Isobe, M. Kimura, S. Ohtsuka

    Proc. of 13th International Conference of the International Association for Computer Methods and Advances in Geomechanics   1 ( 1 )   957 - 963   2011.5

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  • 新潟県中越地震における家屋被害と地形分類の相関分析 Reviewed

    大塚 悟, 藤澤誠二, 落合弘和, 磯部公一, 高原利幸

    土木学会論文集A1(構造・地震工学)   66 ( 1 )   414 - 424   2010.12

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  • 剛塑性有限要素解析による弱層を有する斜面の安定性評価

    保科隆, 大塚悟, 磯部公一

    第55回地盤工学シンポジウム論文集   1 ( 1 )   13 - 18   2010.11

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  • Seismic performance of steel pipe pile foundation supporting an integrated column by multiple steel pipes

    K. Isobe, M. Kimura, S. Ohtsuka

    Proc. of Fourth Japan -Taiwan Joint Workshop   1 ( 1 )   125 - 132   2010.10

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  • 剛塑性有限要素解析による河川堤防の浸透崩壊時刻予測手法の提案 Reviewed

    八木啓介, 中村孝博, 磯部公一, 大塚 悟

    応用力学論文集   13 ( 1 )   379 - 389   2010.7

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  • 剛塑性有限要素解析による地山補強土工法の補強効果の評価 Reviewed

    保科 隆, 瀧本英朗, 田中達也, 磯部公一, 大塚 悟

    応用力学論文集   13 ( 1 )   391 - 400   2010.7

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  • Study on vertical bearing capacity of pile supported by mudstone

    Taka-aki Mizutani, Yoshiaki Kikuchi, Takahiro Yoshida, Satoru Ohtsuka, Eiji Kohama, Tetsuya Kubo

    Proc. of 4th Japan-China Geotechnical Symposium   1 ( 1 )   403 - 408   2010.4

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  • 鋼管柱基礎の静的水平抵抗特性に関する三次元有限要素解析 Reviewed

    磯部公一, 木村 亮, 大塚 悟, 秋山耕士郎

    構造工学論文集A   56A ( 1 )   1041 - 1053   2010.3

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  • Activity for Geo-information Database System of Hokuriku District in Japan

    Satoru Ohtsuka, Yukihiko Kamoi, Koji Ichimura

    International Symposium on Geo-Informatics and Zoning for Hazard Mapping   1 ( 1 )   109 - 112   2009.12

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  • 中越地震斜面・地滑り災害多変量解析における地形情報の精度の影響について

    井上直人, 北田奈緒子, 三村 衛, 大塚 悟

    降雨と地震に対する斜面崩壊機構と安定性評価に関するシンポジム論文集   1 ( 1 )   375 - 378   2009.10

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  • Liquefaction and its influence to house damage in the Niigataken Chuetsu-Oki Earthquake in 2007 Reviewed

    Ohtsuka, S, Isobe, K, Hirade, T, Hayashi, K

    Proc. of International Offshore and Polar Engineering Conference 2009   2 ( 1 )   29 - 36   2009.6

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  • Site investigation and experimental study on slope failure in housing complex constructed by cutting the ground and filling in 2004 Niigataken Chuetsu earthquake Reviewed

    Ohtsuka, S, Isobe, K, Takahara, T

    Proc. of International Offshore and Polar Engineering Conference 2009   2 ( 1 )   533 - 539   2009.6

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  • Consolidation on fill slope failure in Takamachi developed residential land in 2004 Niigataken Chuetsu earthquake Reviewed

    Ohtsuka, S, Isobe, K, Takahara, T

    Proc. of International Conference on Performance-Based Design in Earthquake Geotechnical Engineering   2 ( 1 )   923 - 927   2009.6

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  • Fill slope failure in Takamachi housing complex in the 2004 Niigataken Chuetsu Earthquake Reviewed

    Ohtsuka, S, Isobe, K, Takahara, T

    Proc. of International Conference on Performance-Based Design in Earthquake Geotechnical Engineering   2 ( 1 )   83 - 94   2009.6

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  • 地震と降雨の複合的メカニズムの斜面災害

    大塚 悟

    地質と調査   120 ( 2 )   9 - 13   2009.6

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  • Site Investigation Using the Surface-wave Method in Disaster Area of the Niigataken Chuetsu-oki Earthquake in 2007 Reviewed

    HAYASHI Koichi, HIRADE Tsutomu, ISOBE Koichi, OHTSUKA Satoru

    57 ( 5 )   24 - 27   2009.5

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    Many geotechnical disasters, such as slope failure and liquefaction, occurred in the Niigataken Chuetsu-oki Earthquake in 2007. Most of these damages concentrate on geological boundary such as the foot of sandy dune. In order to delineate geological structure in the disaster area, a series of investigations was carried out. The surface-wave method was carried out firstly. Next borings and soundings were conducted at the selected points based on the Swave velocity model obtained from the surface-wave method. Investigation results clearly showed the efficiency of the investigation method by combining the surface-wave method with the following detailed investigation such as the borings and soundings.

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  • さまざまな工学部学科・専攻で行われた教育改革の実例 Reviewed

    堀宗朗, 木村定雄, 飯塚敦, 大塚悟, 熊谷健一, 齋藤利晃, 田村武, 橋本親典, 平出純一, 山口栄輝

    土木学会論文集   1 ( 1 )   1 - 9   2009.1

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  • EXAMPLES OF EDUCATION SYSTEM RECONSTRUCTION MADE BY ENGINEERING DEPARTMENTS Reviewed

    Muneo HORI, Sadao KIMURA, Atsushi IIZUKA, Satoru OHTSUKA, Kenichi KUMAGAI, Toshiaki SAITOH, Takeshi TAMURA, Chikanori HASHIMOTO, Junnichi HIRADE, Eiki YAMAGUCHI

    Journal of Japan Society of Civil Engineers, Ser. H (Engineering Education and Practice)   1   135 - 143   2009

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    DOI: 10.2208/jscejeep.1.135

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  • Deformation characteristics of clay at slip lines in repetitive type landslides Reviewed

    S. Ohtsuka, K. Isobe

    Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering: The Academia and Practice of Geotechnical Engineering   2 ( 1 )   1682 - 1685   2009

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    DOI: 10.3233/978-1-60750-031-5-1682

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  • Amplification properties of developed residential land for main shock and three aftershocks Reviewed

    Takahara, T, Ohtsuka, S, Isobe, K, Sato, K, Horiguchi, D

    The 14th World Conference on Earthquake Engineering   14 ( 1 )   5601 - 5608   2008.10

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  • Three-dimensional finite element method analysis on steel pipe sheet piles reinforcement method for existing caisson foundation Reviewed

    Isobe, K, Kimura, M, Ohtsuka, S

    The 12th International Conference of International Association for Computer Methods and Advances in Geomechanics   12 ( 1 )   3473 - 3480   2008.10

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  • 7・20 水俣市斜面崩壊の数値解析的考察 Reviewed

    大塚 悟, 岩部 司, 磯部公一, 堀越俊寛

    第4回土砂災害に関するシンポジウム論文集   1 ( 1 )   131 - 136   2008.8

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  • 剛塑性有限要素法による補強土斜面の安定解析

    田中友宏, 大塚 悟, 磯部公一, 谷山慎吾, 佐藤祐司

    第43回地盤工学会研究発表会講演集   43 ( 1 )   1527 - 1528   2008.7

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  • 新潟県中越地震における宅地造成地に与える本震および余震の影響

    高原利幸, 大塚 悟, 磯部公一

    第43回地盤工学会研究発表会講演集   43 ( 1 )   1917 - 1918   2008.7

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  • 河川高水位時の堤体安定性評価に関する事例解析

    坂本和仁, 堀越俊寛, 大塚 悟, 磯部公一, 岩部 司

    第43回地盤工学会研究発表会講演集   43 ( 1 )   1123 - 1124   2008.7

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  • 新潟県中越沖地震による宅地地盤被害(その4 刈羽村)

    磯部公一, 大塚 悟, 平出 務, 林 宏一, 杉村晋之介

    第43回地盤工学会研究発表会講演集   43 ( 1 )   1949 - 1950   2008.7

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  • 塑性指数の異なる中間土の単調および繰返しせん断特性

    山本孝幸, 万所 求, 大塚 悟, 磯部公一

    第43回地盤工学会研究発表会講演集   43 ( 1 )   337 - 338   2008.7

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  • 新潟県中越沖地震による宅地地盤被害(その3 橋場・松波の液状化被害)

    杉村晋之介, 斉藤美咲, 大塚 悟, 磯部公一, 平出 務, 林 宏一

    第43回地盤工学会研究発表会講演集   43 ( 1 )   1747 - 1748   2008.7

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  • 地下水浸透状態における中間土で構成された盛土の崩壊機構に関する振動台実験

    永田隆広, 鈴木幸治, 大塚 悟, 磯部公一

    第43回地盤工学会研究発表会講演集   43 ( 1 )   1585 - 1586   2008.7

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  • 新潟県中越沖地震による宅地地盤被害(その1 概要)

    井上波彦, 飯場正紀, 平出 務, 林 宏一, 大塚 悟, 磯部公一

    第43回地盤工学会研究発表会講演集   43 ( 1 )   1743 - 1744   2008.7

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  • スプライン関数を用いた長体状態量計測法 Reviewed

    小島義孝, 大熊俊明, 川島正樹, 大塚悟

    地すべり   44 ( 6 )   11 - 19   2008.3

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  • Amplification Properties of Developed Residential Land during Earthquake

    Takahara T, Ohtsuka, S, Sato, K, Horiguchi, D

    Proc. of Fifth China-Japan-US Trilateral Symposium on Lifeline Earthquake Engineering   1 ( 1 )   79 - 86   2007.11

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  • Rigid plasticity based stability analysis of reinforced slope Reviewed

    Ohtsuka, S, Inoue, Y, Tanaka, T

    New Horizons in Earth Reinforcement (Proc. of 5th International Symposium on Earth Reinforcement)   1 ( 1 )   447 - 450   2007.11

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  • 新潟県中越地震による地盤の被害と復旧

    田村昌仁, 大塚悟, 松下克也

    建築防災   356 ( 9 )   27 - 34   2007.9

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  • 表面波探査による住宅地盤の耐震性評価と地震による被害事例

    林宏一, 大塚悟, 若井明彦, 菊地康明

    基礎工   35 ( 8 )   67 - 73   2007.8

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  • Shear behavior of clay in slope for pore water pressure increase

    Ohtsuka, S

    proc. of the first China-Japan-Korea Field trip and Workshop on Landslides   1 ( 1 )   103 - 111   2007.7

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  • Normal stress reducing ring shear test on clay caused large deformation-Kaolin clay-

    Kawashima Kensuke, Ohtsuka Satoru, Yoshida Katsumi

    Proceedings of the Japan National Conference on Geotechnical Engineering   39   343 - 344   2004

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    Publisher:The Japanese Geotechnical Society  

    DOI: 10.11512/jiban.JGS39.0.343.0

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  • Analysis of excavated rock plane roughness for rock type and classification

    Hirosaki Daishi, Ohtsuka Satoru, Ozawa Tomokazu, Koumura Seiichi

    Proceedings of the Japan National Conference on Geotechnical Engineering   39   563 - 564   2004

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    DOI: 10.11512/jiban.JGS39.0.563.0

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  • Finite element method for landslide analysis No.10

    OHTSUKA Satoru

    Landslides   41 ( 3 )   309 - 312   2004

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    DOI: 10.3313/jls.41.3_309

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  • Normal stress reducing ring shear test on clay caused large deformation-Okimi clay-

    Yoshida Katasumi, Kawashima Kensuke, Ohtsuka Satoru

    Proceedings of the Japan National Conference on Geotechnical Engineering   39   341 - 342   2004

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    DOI: 10.11512/jiban.JGS39.0.341.0

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  • An Inverse Approach for Shallow Footing Resting on Dense Sand

    Husna Asmaul, Ohtsuka Satoru

    Proceedings of the Japan National Conference on Geotechnical Engineering   39   1413 - 1414   2004

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    It is generally known there are many factors affect the shear strength of sandy soil, such as stress and strain dependency, dilatancy effect, anisotropy, scale-effect and so on. It must be very difficult to solve these problems clear, however, the most important thing from practical point of view is to evaluate the reliable strength and stress-strain characteristics of sand taking into account the effect of these factors. It has not make clear yet in designing of many geotechnical structures.This study carried out an inverse approach of soil constant (angle of shear resistance) for ultimate bearing capacity of sandy soil obtained in centrifuge model tests of Japanese standard Toyoura sand. The concept of non-associated flow was employed into rigid plastic finite element method (RPFEM). The computation was led for both circular and strip footing with various condition of the footing width and the thickness of ground layer. The influence factors on ultimate bearing capacity assessment were observed in comparison with the experimental results and also conventional methods.The numerical result reported that the inversed angle of shear resistance was lower than it obtained on triaxial compression test and expressed the design constant for practical use. The inverse result on strip footing of residual state plainly showed the reliability of the inverse method on ultimate bearing capacity of uniform sandy soil. Discussion was made in comparison with the physical soil constant and its applicability to direct analysis of ultimate bearing capacity for other conditions.

    DOI: 10.11512/jiban.JGS39.0.1413.0

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  • Application of rigid plastic finite element method to pull-up bearing capacity analysis on T-type foundation of power transmission tower

    Hashizume Masahiro, Ueda Minoru, Suzuki Takashi, Ohtsuka Satoru

    Proceedings of the Japan National Conference on Geotechnical Engineering   39   1355 - 1356   2004

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    DOI: 10.11512/jiban.JGS39.0.1355.0

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  • Shear strength property of rock joint due to joint roughness

    Ozawa Tomokazu, Ohtsuka Satoru, Hirosaki Daishi, Doi Masanobu

    Proceedings of the Japan National Conference on Geotechnical Engineering   39   565 - 566   2004

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    DOI: 10.11512/jiban.JGS39.0.565.0

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  • Rigid plastic finite element analysis of slope with low strength thin layer

    Namba Masashi, Ohtsuka Satoru

    Proceedings of the Japan National Conference on Geotechnical Engineering   39   2177 - 2178   2004

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    DOI: 10.11512/jiban.JGS39.0.2177.0

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  • 剛塑性有限要素法の3次元地すべり安定解析への適用

    鈴木 隆, 橋詰 正広, 大塚 悟, 上田 稔

    地盤工学研究発表会 発表講演集   38   2225 - 2226   2003

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    三次元の斜面崩壊を取り扱う解析では、破壊モードを仮定した上で、極限状態のつり合い条件よりすべり安全率を求める方法が一般的に用いられる。そこで、今回極限平衡法と同様に地盤の強度定数のみを用いて安定性を評価する剛塑性有限要素法により、斜面崩壊で見られる局所的なせん断層(すべり線)を表現することを試みた。解析に用いた地すべりの規模は幅約300m,延長600m,すべり面の最大深度が80mに達する大規模なものである。この他、従来の三次元解析(Hovland法)に比べてどの程度の安全率が得られるかを、単純な斜面を事例としたモデルにより確認した。

    DOI: 10.11512/jiban.JGS38.0.2225.0

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  • Slope Stability Analysis with Rigid-Plastic Finite Element Method

    OHTSUKA Satoru, MIYATA Yoshifumi, IKEMOTO Hirofumi, IWABE Tsukasa

    Journal of the Japan Landslide Society   38 ( 3 )   235 - 243   2001.12

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    Rigid plastic finite element method was formulated for slope stability assessment by introducing the shear strength reduction coefficient to define the factor of safety used in slope stability. The framework of the proposed method was clarified in comparison with the limit equilibrium method based on slice method. The limit equilibrium method was shown to coincide with the upper bound theory in limit analysis and the process of minimizing the factor of safety for possible slip line was clarified to be important from the viewpoint of limit analysis. Rigid plastic FEM analysis has the advantages of (1) no need to assume the failure mode prior to analysis, (2) mathematical minimization of factor of safety, (3) use of constitutive equation and (4) taking account of dilatancy property of geo-material. The factor of safety was examined with simple slope for various conditions. It shows the good agreement with conventional methods and the applicability of proposed method was clarified. Case studies shows non-linear slip lines were well obtained corresponding to geometry and geology of slopes in the analysis. In some cases the sliding mass included several shearing zones inside and this fact suggests the existence of complicated failure mode not to be covered in the conventional methods.

    DOI: 10.3313/jls1964.38.3_235

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  • Failure mechanism of clay in pore water pressure loading test

    OHTSUKA Satoru, MIYATA Yoshifumi

    Journal of the Japan Landslide Society   37 ( 4 )   10 - 17   2001.3

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    Pore water pressure loading test of clay was carried out to investigate a shear resistance of clay in land-slide slope. From the observation on shear deformation of the clay, two threshold magnitudes for pore water pressure were found out where the deformation of testing specimen rapidly increased. Through a series of pore water pressure loading tests of clay, the yield points were found to locate on the critical state line de-scribed by the shear resistance angle φ'. It suggests the design based on the yield point corresponds to that of residual strength. The transmittance time of pore water pressure from the bottom to the top of soil specimen was measured to get longer after the pore water pressure was over the yield point. The deformation of soil specimen took place very slowly as the pore water pressure closing to the failure point. The reason for the slow failure was concluded that the soil deformed with the water migration and the progressive failure of soil specimen proceeded with strain softening of soil. It suggests the reason for the slow failure of landslide. The pore water pressure loading test was simulated with the constitutive equation by Hashiguchi. The yield and failure points were shown to be well estimated.

    DOI: 10.3313/jls1964.37.4_10

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  • EFFECT OF ASPERITY SHAPE ON SHEAR STRENGTH CHARACTERISTICS OF ROCK JOINT

    DOI Masanobu, OHTSUKA Satoru, MOTEGI Ryushi

    Doboku Gakkai Ronbunshu   659   141 - 152   2000.9

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    This paper employed the numerical procedure based on the lower bound theorem by introducing the contact condition along rock joint to clarify the mechanical property of joint strength. By simplifying the complicated real geometry of rock joint, the effect of triangle shape asperity on joint strength was investigated. The applicability of employed method was examined in comparison with both the experiments by Patton and the upper bound solutions by limit analysis. The failure mechanism of rock joint was shown to change with the increasing normal stress from the sliding failure along the asperity to the mixed failure of sliding along the asperity and shearing of asperity. It was found that the non-linearity in joint shear strength for normal stress was caused by the change in failure mechanism of rock joint.

    DOI: 10.2208/jscej.2000.659_141

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  • Pore water pressure loading tests of a clay

    S Ohtsuka, Y Miyata, H Toyota

    SLOPE STABILITY ENGINEERING, VOLS 1 & 2   731 - 734   1999

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  • ULTIMATE BEARING CAPACITY OF FOOTING CONSIDERING STATIC SOIL-FOOTING INTERACTION

    OHTSUKA Satoru, YAMADA Eiji, MATSUO Minoru

    Doboku Gakkai Ronbunshu   582   151 - 162   1997.12

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    The static soil-footing interaction changes with the applied load in bearing capacity problem. The interaction at the limit state is required as the boundary condition in bearing capacity analysis so that the rigidity of footing is, hitherto, idealized as perfectly flexible or rigid to simplify the problem. This study presents the ultimate bearing capacity of footing by taking account of the finite rigidity of footing and the change in soil-footing interaction. The lower bound theorem in shakedown analysis is employed to consider the interaction redistribution. The ultimate bearing capacities of footing against uniform and eccentric concentrated load applications are estimated and discussed in comparison with the reported experiments. The change in ultimate bearing capacity with the rigidity of footing is taken into consideration in view point of static soil-footing interaction.

    DOI: 10.2208/jscej.1997.582_151

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Books

  • 解体新書・大河津分水可動堰

    大塚 悟( Role: Joint author)

    (公社)土木学会  2014.9 

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  • すべり面

    山田正雄他( Role: Joint author)

    公益社団法人 日本地すべり学会  2013.3 

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  • 地震地すべり

    大塚 悟ほか( Role: Joint author)

    日本地すべり学会  2012.2  ( ISBN:9784902628036

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MISC

  • Experimental measurement of flow in granular porous media focusing on tortuosity

    渡邉尚幸, 山本七輝, 福元豊, 大塚悟

    地盤工学研究発表会(Web)   59th   2024

  • Limit load curve for vertical eccentricity load and inclined load applied for foundation on sandy ground

    安藤康介, IQBAL Tahir, 大塚悟, 福元豊

    地盤工学研究発表会(Web)   59th   2024

  • Proposal of Ultimate Bearing Capacity Equation for Sandy Ground for Vertical Loads

    池田澪央, IQBAL Tahir, 大塚悟, 福元豊

    地盤工学研究発表会(Web)   58th   2023

  • Observation of boundaries of different grain sizes using transparent soil focusing on hydraulic tortuosity

    山本七輝, 大下倭駆, 福元豊, 大塚悟

    地盤工学研究発表会(Web)   58th   2023

  • AIを用いた斜面の広域危険度評価の試み

    會川健朗, 片平耀款, 大塚悟, 福元豊

    日本応用地質学会北陸支部研究発表会論文集   2021   2022

  • Compaction property of clayey soil against repeated consolidation

    伊與和真, 大塚悟, 福元豊

    地盤工学研究発表会(Web)   57th   2022

  • Attempt for estimating high risk slope failure block by machine learing and image recognition

    會川健朗, 片平耀款, 大塚悟, 福元豊, 岡滋晃, 鬼束俊一, 河村直明

    地盤工学研究発表会(Web)   57th   2022

  • Observation of seepage flow in pore by transparent sand from different cross-sections

    大下倭駆, 平田壮, 福元豊, 大塚悟

    地盤工学研究発表会(Web)   57th   2022

  • 屈折率マッチング技術とステレオ撮影を併用した浸透流速の3方向成分の計測

    平田壮, 大下倭駆, 福元豊, 大塚悟

    農業農村工学会誌   90 ( 7 )   2022

  • Model test on compaction effect of loose sandy soils by gravel pile

    金子泰士, 大塚悟, 福元豊

    地盤改良シンポジウム論文集(CD-ROM)   15th   2022

  • Experimental Measurement of Three Velocity Components of Seepage Flow inside Pore of Soil Particles Using Transparent Soils

    平田壮, 関口泰徳, 福元豊, 大塚悟

    地盤工学研究発表会(Web)   56th   2021

  • Development of Method for Evaluating the Extensive Hazard Level of Slopes Using Machine Learning

    片平耀款, 大塚悟, 福元豊, 岡滋晃, 河村直明, 塚田智之

    地盤工学研究発表会(Web)   56th   2021

  • 屈折率マッチング技術とステレオ撮影を併用した浸透流速の3方向成分の計測

    平田壮, 大下倭駆, 福元豊, 大塚悟

    農業農村工学会京都支部研究発表会講演要旨集   78th   2021

  • Experimental study on quantitative evaluation of liquefaction countermeasures by using gravel piles

    中島啓太, 新宮康希, 大塚悟, 福元豊

    地盤工学研究発表会(Web)   55th   2020

  • Direct observation of seepage flow using refractive index matching technology: Examination by changing soil particle arrangement

    関口泰徳, 塩原祐希, 福元豊, 大塚悟

    地盤工学研究発表会(Web)   55th   2020

  • HYDRODYNAMIC CHARACTERISTICS AND STABILITY OF GROUNDSILL BLOCKS WITH CONSIDERING SEEPAGE AND HYDRAULIC JUMP IN RIVER

    YANG Hongxuan, 山本陽子, 福元豊, 細山田得三, 大塚悟, 福島雅紀

    河川技術論文集   26 (CD-ROM)   2020

  • Study on bearing capacity formula of intermediate soil considering the effect of foundation size

    DUNG Huynh Anh, SON Dang Hoang, 大塚悟, 福元豊

    地盤工学研究発表会(Web)   55th   2020

  • Periodic consolidation characteristics of natural sedimentary clay in the former Shiunjigata

    新宮康希, 衣川元貴, 大塚悟, 福元豊, 畠山正則

    地盤工学研究発表会(Web)   55th   2020

  • Bearing Capacity of Footing Resting on Sand for Eccentric Vertical Load Reviewed

    Quang, P., N., Ohtsuka, S., Isobe, K., Fukumoto, Y.

    Geotechnics for Sustainable Infrastructure Development (Proceedings of the 4th Geotech Hanoi)   1135 - 1142   2019.11

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  • 2-D numerical simulation of weathering process of geomaterials by particle simulation model with swelling and shrinking

    立花賢吾, 輪島僚也, 福元豊, 大塚悟

    地盤工学研究発表会(Web)   54th   2019

  • 基礎の寸法効果を考慮した中間土地盤の支持力式に関する研究

    HUYNH Anh Dung, PHAM Ngoc Quang, 大塚悟, 福元豊, 保科隆

    地盤工学研究発表会(Web)   54th   2019

  • 透明砂を用いた浸透流の直接計測手法による層流-乱流域の観察

    塩原祐希, 宇井智章, 福元豊, 大塚悟

    地盤工学研究発表会(Web)   54th   2019

  • Experiments on reinforcement method of resilient bank for overflowing water

    坂本恭史, 大塚悟, 福元豊

    地盤工学研究発表会(Web)   54th   2019

  • Quantitative evaluation of liquefaction countermeasure method with gravel pile

    新宮康希, 大塚悟, 福元豊, 栗田修平

    地盤工学研究発表会(Web)   54th   2019

  • Numerical analysis of weathering process of geomaterials by using the 3-D DEM model with changes in size of particles

    福元豊, 輪島僚也, 立花賢吾, 大塚悟

    計算工学講演会論文集(CD-ROM)   24   2019

  • 背面地盤の変状を考慮した石積構造物の2次元DEMモデル

    衛藤修平, 福元豊, 大塚悟

    日本地すべり学会研究発表会講演集(CD-ROM)   58th   2019

  • 透明土を用いた浸透破壊に伴う土粒子と浸透流の直接観察

    宇井智章, 福元豊, 大塚悟

    農業農村工学会京都支部研究発表会講演要旨集   75th   2018

  • 土骨格中の浸透流の直接的観察手法の検討 その2:模型実験と数値解析の比較

    福元豊, 宇井智章, 清野颯, 大塚悟

    地盤工学研究発表会発表講演集(CD-ROM)   53rd   2018

  • 屈折率マッチング手法を応用した土骨格内部の浸透流の直接観察

    宇井智章, 福元豊, 大塚悟

    農業農村工学会大会講演会講演要旨集(CD-ROM)   2018   2018

  • 柏崎平野における地震後広域地盤沈下に関する検討

    坂本恭史, 長谷川拓也, 大塚悟, 福元豊

    地盤工学研究発表会発表講演集(CD-ROM)   53rd   2018

  • 土骨格中の浸透流の直接的観察手法の検討 その1:RIMSを用いた模型実験

    宇井智章, 清野颯, 福元豊, 大塚悟

    地盤工学研究発表会発表講演集(CD-ROM)   53rd   2018

  • ケーソン海岸防波堤の津波に対する安定解析

    HO Sy Quoc, 高木大地, 大塚悟, 福元豊, 山崎浩之, 金田一広

    地盤工学研究発表会発表講演集(CD-ROM)   53rd   2018

  • Direct numerical simulation method of seepage flow in soils: Comparing with a model experiment

    福元豊, 宇井智章, 清野颯, 大塚悟

    計算工学講演会論文集(CD-ROM)   23   2018

  • グラベルパイルの砂質地盤の締固め効果に関する小型模型試験

    栗田修平, 猪狩貴寛, 大塚悟, 福元豊, 折戸清治

    地盤工学研究発表会発表講演集(CD-ROM)   53rd   2018

  • DEMモデルによる膨潤性を持つ泥岩のスレーキングシミュレーション

    輪島僚也, 福元豊, 大塚悟

    地盤工学研究発表会発表講演集(CD-ROM)   53rd   2018

  • Particle simulation model for geomaterials including swelling clay mineral

    22   4p   2017.5

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  • 模型実験による地盤材料の侵食強さの評価方法の検討

    清野颯, 梅沢圭佑, 福元豊, 大塚悟

    地盤工学研究発表会発表講演集(CD-ROM)   52nd   2017

  • 水中での砂柱崩壊実験に基づく土粒子-間隙水連成計算手法の高度化

    齋藤雅史, 福元豊, 大塚悟

    農業農村工学会大会講演会講演要旨集(CD-ROM)   2017   2017

  • 土粒子-間隙水連成計算モデルによる水中での砂柱の崩壊シミュレーション

    齋藤雅史, 福元豊, 大塚悟

    農業農村工学会京都支部研究発表会講演要旨集   74th   2017

  • 地盤中の細粒分移動を直接観察するための模型実験方法の検討

    清野颯, 宇井智章, 福元豊, 大塚悟

    農業農村工学会京都支部研究発表会講演要旨集   74th   2017

  • 実物大スケールで応用するための3次元個別要素モデルによる地盤材料の強度定数の表現

    瓜谷匠, 福元豊, 大塚悟

    土木学会年次学術講演会講演概要集(CD-ROM)   72nd   2017

  • 膨潤性粘土鉱物を有する粘土鉱物の圧縮・膨張特性

    金田陽樹, 高木大地, 大塚悟, 福元豊

    地盤工学研究発表会発表講演集(CD-ROM)   52nd   2017

  • 粒状体モデルによる膨潤性粘土鉱物を含む泥岩の変形シミュレーション

    福元豊, 藤川聡司, 大塚悟

    地盤工学研究発表会発表講演集(CD-ROM)   52nd   2017

  • 締固めグラベルパイルによる宅地地盤の液状化対策効果に関する検討

    猪狩貴寛, 大塚悟, 福元豊, 折戸清治

    地盤工学研究発表会発表講演集(CD-ROM)   52nd   2017

  • 内部侵食に伴う細粒分流出の小型模型装置内での観察

    清野颯, 福元豊, 大塚悟

    農業農村工学会大会講演会講演要旨集(CD-ROM)   2017   2017

  • Coupled particle-fluid numerical simulations of seepage flow and fine soil particles

    21   3p   2016.5

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  • 土の侵食特性の定量的な測定方法の検討

    梅沢圭佑, 福元豊, 大塚悟

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

  • ロックフィルダムの強震時変状の3次元個別要素法シミュレーション

    瓜谷匠, 福元豊, 大塚悟

    計算工学講演会論文集(CD-ROM)   21   2016

  • 粒径差のある粒状体に対する内部侵食の数値計算モデル

    福元豊, 大塚悟

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

  • 模型実験による土の侵食強さを表す物理量の抽出

    梅沢圭佑, 清野楓, 福元豊, 大塚悟

    農業農村工学会京都支部研究発表会講演要旨集   73rd   2016

  • 地盤材料の強度を表現する3次元粒状体モデルの検討と実物大スケールでの応用

    瓜谷匠, 福元豊, 大塚悟

    農業農村工学会京都支部研究発表会講演要旨集   73rd   2016

  • 地震時の擁壁主働土圧に関する検討

    山根悠司, LE Hong Nguyen, 大塚悟, 福元豊

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

  • 粒子ベースの数値シミュレーション手法によるロックフィルダムの破壊挙動解析

    瓜谷匠, 福元豊, 大塚悟

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

  • 20308 The analysis example of combined bearing capacity of spread foundation using rigid plastic FEM

    AOKI Masamichi, KANEDA Kazuhiro, OHTSUKA Satoru

    Summaries of technical papers of annual meeting   2015   615 - 616   2015.9

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  • Ultimate bearing capacity of spread foundation on sandy soils for inclined load by rigid plastic FEM

    20   5p   2015.6

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  • Development of moving particle simulation method using a rigid plastic constitutive model Reviewed

    K. Isobe, S. Ohtsuka, T. Hoshina

    Geomechanics from Micro to Macro, Vols I and II   995 - 998   2015

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  • Estimation of Reinforcement Effect on Slope Stability by Nailing Method based on Rigid Plastic Finite Element Analysis

    ( 39 )   51 - 54   2014.11

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  • 20296 The bearing capacity of spread foundation considering inclined load and scale effect using rigid plastic FEM

    AOKI Masamichi, KANEDA Kazuhiro, HAMADA Junji, TANIKAWA Tomohiro, OHTSUKA Satoru

    Summaries of technical papers of annual meeting   2012   591 - 592   2012.9

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  • 20297 The bearing capacity of spread foundation using rigid plastic FEM

    KANEDA Kazuhiro, SHIGENO Yoshimasa, HAMADA Junji, TANIKAWA Tomohiro, AOKI Masamichi, OHTSUKA Satoru

    Summaries of technical papers of annual meeting   2012   593 - 594   2012.9

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  • 自然現象を観察する科学:応用地質学への期待 Invited

    大塚 悟

    新潟応用地質研究会誌   79 ( 1 )   1 - 1   2012.1

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  • 斜面安定(3)対策工(7.地盤防災,総括,<特集>第47回地盤工学会研究発表会)

    大塚 悟

    地盤工学会誌   60 ( 12 )   24 - 24   2012

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  • 30. GIS based analysis of slope disaster in 2004 Mid-Niigata Prefecture Earthquake

    Ohtsuka Satoru

    24   59 - 60   2012

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  • 46回地盤工学研究発表会一般発表総括 地すべり・落石(1)

    大塚 悟

    地盤工学会誌   59 ( 12 )   34 - 34   2011.12

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  • 巻頭言

    大塚 悟

    2004年新潟県中越地震地すべり記録集   1 - 1   2011.9

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  • 35 年の実績を誇る、長岡技術科学大学の実務訓練制度の歩みと発展

    大塚 悟

    新潟自治   48 ( 1 )   25 - 30   2011.7

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  • Stability analysis on reverse dis slope including low strength seam layer

    16   4p   2011.5

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  • Vision of JGS Hokuriku Branch

    OHTSUKA Satoru, MATSUMOTO Tatsunori

    59 ( 2 )   2 - 3   2011.2

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  • 第45回地盤工学研究発表会を終えて

    大塚 悟

    地盤工学会誌   58 ( 12 )   1 - 1   2010.12

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  • 地震(地盤防災1)第45回地盤工学研究発表会

    大塚 悟

    地盤工学会誌   58 ( 12 )   31 - 32   2010.12

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  • Internal Movement of Complex Slope Disaster by Rainstorm and Earthquake

    58 ( 2 )   54 - 54   2010.2

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  • 中越・中越沖地震における宅地地盤の繰り返し液状化に関する現地調査

    大塚 悟

    「北陸地域の活性化」に関する研究助成事業論文集   15   25 - 30   2010

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  • 第1章とりまとめ

    大塚 悟

    降雨と地震に対する斜面崩壊機構と安定性評価に関する委員会報告書   2 - 51   2009.10

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  • 地盤の液状化(刈羽村稲場)

    大塚 悟, 磯部公一

    新潟県中越地震災害調査報告書   3-3-1 - 3-3-5   2009.2

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  • 盛土の地震時挙動((2)土構造物等の地震時挙動,7.地盤防災,<特集>第44回地盤工学研究発表会)

    大塚 悟

    地盤工学会誌   57 ( 12 )   31 - 31   2009

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  • Site Investigation Using Surface-wave Method and Micro-tremor Array Measurements in Disaster Area of The Niigataken Chuetsu-oki Earthquake in 2007

    HAYASHI Koichi, HIRADE Tsutomu, OHTSUKA Satoru, ISOBE Koichi

    118   97 - 100   2008.5

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  • 類似の被害事例の発掘と収集/潜在する課題への対応

    大塚 悟, 細山田得三, 豊田浩史, 磯部公一, 高原利幸

    活褶曲帯における防災シンポジウム 2004年新潟県中越地震被害の教訓にもとづく今後の課題・対策への提言   75 - 103   2008.3

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  • 新潟県中越沖地震における宅地の液状化被害

    大塚 悟, 磯部公一

    長岡技術科学大学新潟県中越沖地震災害調査団最終報告書   3 - 11   2008.3

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  • DS-10 降雨と地震の複合災害に対する斜面崩壊機構と安定性評価(ディスカッションセッション,<特集>第43回地盤工学研究発表会)

    大塚 悟

    地盤工学会誌   56 ( 12 )   22 - 22   2008

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  • 新潟県中越沖地震における液状化による宅地被害調査

    大塚 悟, 磯部公一

    長岡技術科学大学新潟県中越沖地震災害調査団報告書(速報版)   5 - 8   2007.10

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  • 類似被害事例の発掘と収集/潜在する課題への対応 Invited

    大塚悟, 細山田得三, 豊田浩史, 佐藤啓介, 高原利幸, 大澤範一

    2004年新潟県中越地震被害の科学的調査今後の課題・対策への提言, 講演概要集   113 - 133   2007.3

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  • 地盤防災 : 地すべり・落石 その他

    大塚 悟

    土と基礎 = Soil mechanics and foundation engineering   54 ( 12 )   65 - 66   2006.12

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  • A SHEAR STRENGTH MODEL FOR ROCK JOINTS USING GEOMETRIC INFORMATION ON JOINT ASPERITY

    OZAWA Tomokazu, OHTSUKA Satoru, DOI Masanobu

    ( 813 )   191 - 202   2006.3

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  • 盛土等構造物の被害 (総特集 2004年新潟県中越地震) -- (4章 中越地震がもたらした災害)

    大塚 悟

    号外地球   ( 53 )   132 - 138   2006

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  • JGS Propositions on Geotechnical Damage of the 2004 Niigataken Chuetsu Earthquake(<Theme>Niigataken Chuetsu Earthquake, Fukuokaken Seiho-Oki Earthquake)

    Kokusyo Takaji, Ohtsuka Satoru

    53 ( 11 )   3 - 11,図巻頭2p   2005.11

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    The 2004 Niigataken Chuetsu Earthquake led to enormous damages on earth structures that we had have not experienced recently. The magnitude of the earthquake was 6.8 and the seismic intensity registered a higher 6 to 7 on the 7-point Japanese intensity scale, which corresponded to the level 2 seismic motion. The magnitude of this earthquake is not so huge and earthquakes of the same level will take place often in Japan. The damage on earth structures was so heavy that it affects the protection measures for earthquake disaster in Japan, especially on slope disaster. The JGS has been active not only to send the disaster investigation team and to have the report symposium, but also to organize the disaster investigation committee to make clear the damages and causes of enormous disaster. The JGS announced the propositions on geotechnical damages of the 2004 Niigataken Chuetsu Earthquake to contribute the society. This reports the content of propositions with the explanation of typical geotechnical damages in the earthquake.

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    Other Link: http://dl.ndl.go.jp/info:ndljp/pid/10444325

  • 切土斜面の地震被害 (特集 新潟県中越地震の教訓と対策)

    大塚 悟

    基礎工   33 ( 10 )   70 - 73   2005.10

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  • Experimental Study on Shear Strength Properties of Artificial Rock Joint

    Matsumoto Yoshinori, Doi Masanobu, Ohtsuka Satoru

    Research report of Takamatsu National College of Technology   40   31 - 35   2005.3

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    A rock mass naturally includes some cracks inside in formation. The size of crack widely varies from minute to huge. The stability of rock structures including macroscopic cracks depends on the configuration and the shear strength property of the rocks. The purpose of this experimental study is to investigate the effect of asperity shape of rock joint on shear strength of rock joint, which is made of artificial plaster material. By simplifying the complicated real geometry of rock joint, the effect of various asperity shape on joint strength was investigated. This study, was investigated with ordinary box shear test. Through many experimental studies with respect to various types of shape with the first and second order of asperity, it could be shown to estimate the relationship asperity shape and the joint shear strength.

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  • Shear strength of overconsolidated clay for repeats of pore water pressure loading

    OHTSUKA Satoru, MIYATA Yoshifumi, IWABE Tsukasa

    Journal of the Japan Landslide Society   41 ( 5 )   475 - 482   2005.1

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  • Geo-disaster Induced by Niigataken-Chuetsu Earthquake

    ( 49 )   377 - 381   2005

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    Other Link: http://hdl.handle.net/2433/26629

  • 1. 7.13新潟豪雨災害における河川被害と土砂災害(<特集記事>平成16年豪雨による土砂災害)

    大塚 悟

    自然災害科学   24 ( 2 )   107 - 117   2005

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  • 地盤材料 ; 中間土とメタンハイドレート, 砂質土(一般), 不飽和土(変形, 強度)

    大塚 悟

    土と基礎 = Soil mechanics and foundation engineering   51 ( 12 )   38 - 39   2003.12

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  • 剛塑性有限要素法の斜面安定解析への適用

    大塚悟

    豪雨時の斜面崩壊のメカニズムおよび危険度予測に関するシンポジウム, 2003   2003

  • Reliability of the Conventional φ_u=0 Stability analysis

    ASAOKA Akira, OHTSUKA Satoru, SUZUKI Makoto, KANEDA Kazuhiro

    50 ( 8 )   3 - 5   2002.8

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    The circular arc stability analysis of a clay foundation based on the φ_u=0 assumption is investigated by examining conventional procedures for determining undrained shear strength of the clay. In a conventional analysis procedure, strength anisotropy, the difference between plain strain strength and axi-symmetric strength, and partial drain effect on the strentgth, for example, are all neglected for simplicity. However, the conventional analysis is still found to yield, in some cases, acceptable accuracy due to a "lucky harmony" among errors. The demand for the observational support to the conventional analysis is newly identified in order to avoid the accidental lucky harmony.

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  • 中間土(3.地盤材料)

    大塚 悟

    土と基礎   49 ( 12 )   22 - 22   2001

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  • 剛塑性有限要素法による斜面安定解析

    大塚悟

    地すべり   38 ( 3 )   47 - 52   2001

  • 6. 地盤と構造物 ; 抗土圧構造物 (擁壁 ・ アンカー, 土留め ・ アンカー1・2, 動的試験1・2)

    大塚 悟

    土と基礎 = Soil mechanics and foundation engineering   48 ( 12 )   47 - 48   2000.12

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  • 間隙水圧載荷試験による地すべり発生機構の考察

    大塚 悟

    財団法人環境地質科学研究所研究年報   ( 11 )   125 - 133   2000

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  • 不連続面の接触条件を考慮した岩盤の支持力解析(『地盤工学会論文報告集』Vol.39,No.6 (1999年12月発行)掲載論文の概要)

    大塚 悟, 土居 正信

    土と基礎   48 ( 1 )   64 - 64   2000

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  • BEARING CAPACITY ANALYSIS OF ROCK MASS TAKING ACCOUNT OF CONTACT INTERACTION ALONG DISCONTINUOUS LINES

    OHTSUKA Satoru, DOI Masanobu

    Journal of the Japanese Geotechnical Society   39 ( 6 )   91 - 101   1999.12

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    A new stability analysis of rock mass is proposed by taking account of contact interaction along macroscopic discontinuous lines. The lower bound theorem in plasticity is employed with the finite element discretization technique. The joint element is introduced to describe the equilibrium equation in terms of stress in rock and contact traction along discontinuous line. The shearing behavior of joint as sliding and detachment is modeled as a rigid perfectly plastic one. The applicability of proposed method has been investigated in detail in comparison with the upper bound solutions by Tamura (1990). For every case, both computation results matched well indicating that both methods could be applicable to the stability estimation of a rock mass including macroscopic cracks inside. The ultimate bearing capacity of ground which includes discontinuous lines inside has been further assessed to investigate the effect of geometrical configuration and shearing property of discontinuous lines on the total stability. In particular, non-linear shearing property of discontinuous line against confining stress has been brought into the proposed method. The wide applicability of the proposed method to stability estimation of rock mass is clearly confirmed through some numerical studies.

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  • 地盤材料 (3)一般土 (一般土)

    大塚 悟

    土と基礎 = Soil mechanics and foundation engineering   47 ( 12 )   22 - 23   1999.12

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  • 剛塑性有限要素法を用いた地すべり安定解析に関する基礎的検討

    大塚 悟

    研究年報   ( 10 )   22 - 31   1999

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  • 地震に対する土構造物の安定解析

    大塚 悟, 山田 英司, 松尾 稔

    土と基礎 = Soil mechanics and foundation engineering   46 ( 4 )   74 - 74   1998.4

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  • STABILITY ANALYSIS OF EARTH STRUCTURES RESISTING EARTHQUAKE

    OHTSUKA Satoru, YAMADA Eiji, MATSUO Minoru

    Journal of the Japanese Geotechnical Society   38 ( 1 )   195 - 205   1998.3

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    This study proposes two methods of stability for earth structures resisting earthquakes based on the shakedown theory and discusses their applicability in practice. One is a stability method for repetitive static loads based on the seismic coefficient concept (Method A) and the other is a stability method which considers the acceleration time history of the earthquake accurately (Method B). The applicability of Method B was evaluated for both sine and irregular acceleration waves. The applicability of the seismic coefficient method (Method A) is discussed in comparison with Method B. The conclusions from this study are as follows : 1) The effects of periods of enforced accelerations on embankment stability are suitably evaluated with Method B. The stability depends not only on the enforced acceleration but also the dynamic properties of the subsoil profile. The resonance of embankment to the enforced acceleration was simulated. 2) The result of Method A was coincident with that of Method B for the long period case.

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  • Seismic stability of earth structures dependent on loading history

    S Ohtsuka, E Yamada, PT Simatupang

    DEFORMATION AND PROGRESSIVE FAILURE IN GEOMECHANICS - IS-NAGOYA'97   565 - 570   1997

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  • Stability analyses of embankment on soft clays against earthquakes

    S Ohtsuka, E Yamada

    PROCEEDINGS OF THE FOURTEENTH INTERNATIONAL CONFERENCE ON SOIL MECHANICS AND FOUNDATION ENGINEERING, VOL 1   1   715 - 718   1997

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  • Bearing capacity analysis of reinforced ground

    S Ohtsuka, E Yamada, M Matsuo

    EARTH REINFORCEMENT, VOL 1   1   647 - 652   1996

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  • 土圧, アンカー, 泥水

    大塚 悟

    土と基礎   43 ( 12 )   32 - 32   1995

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  • 地盤の支持力(<小特集>第29回土質工学研究発表会)

    大塚 悟

    土と基礎   42 ( 12 )   31 - 31   1994

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  • 分割法による斜面安定解析法の塑性力学的考察

    大塚悟

    第36回土質工学シンポジウム平成3年度発表論文集   13 - 18   1991

  • Bearing Capacity Analysis of a Normally Consolidated Clay Foundation

    ASAOKA AKIRA, OHTSUKA SATORU

    Journal of the Japanese Society of Soil Mechanics and Foundation Engineering   27 ( 3 )   p58 - 70   1987.9

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    In this research an attempt is made to derive a general procedure of determining ultimate bearing capacity of a normally consolidated clay foundation as a function of a loading history taking into account a drainage condition during the loading. The analysis procedure is based on the critical state concept with the use of rigid plastic finite element method. The plastic flow at critical state introduced in the analysis is derived from Sekiguchi-Ohta's yield function which evaluates anisotropic deformation-strength characteristics of anisotropically, normally consolidated clays.Strain hardening effect on the magnitude of ultimate bearing capacity is newly analyzed under the conditions of both undrained, instantaneous loading and partially drained, gradual load application, from which the bearing capacity is obtained as being dependent of a loading history.

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  • The Analysis of Failure of a Normally Consolidated Clay Foundation under Embankment Loading

    ASAOKA AKIRA, OHTSUKA SATORU

    Journal of the Japanese Society of Soil Mechanics and Foundation Engineering   26 ( 2 )   p47 - 59   1986.6

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    In this research an attempt is made to derive the following two approaches of arithmetic methods of evaluating ultimate bearing capacity of normally consolidated clay foundation subject to partial loading such as embankment with finite width. The two approaches are as follows : (1) Finite element deformation analysis of elasto-plastic clay foundation including consolidation behavior, and(2) Limit state analysis by rigid plastic finite element method.In the former analysis, the stiffness factor of clay foundation in terms of effective stresses is newly introduced, from which the definition of total failure of clay foundation is freshly made. In the latter analysis, stress induced anisotropy of undrained shear strength of clay is newly introduced so that the consistency be held between the limit analysis and load deformation analysis.Main conclusions obtained in the present study are as follows : (1) The solution of rigid plastic finite element analysis is shown to be very close to the solution obtained in a deformation analysis as far as undrained condition is concerned.(2) The effect of partial drainage expected during gradual load application is found to be less than 30% of undrained bearing capacity when the loading rate is within the range commonly used in engineering practice.

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Awards

  • 令和5年度事業企画賞(地盤工学会)

    2024.6   公益社団法人 地盤工学会   令和5年度事業企画賞(地盤工学会)

    北陸支部第57回地盤工学研究発表会実行委員会(実行委員長大塚悟)および北陸支部

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  • 新潟日報文化賞(産業技術部門)

    2023.11   (株)新潟日報社  

    大塚 悟

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  • 研究業績賞

    2017.4   (公)地盤工学会北陸支部  

    大塚 悟

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  • 功労賞

    2008.5   (社)地盤工学会  

    大塚 悟

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    Award type:Award from Japanese society, conference, symposium, etc.  Country:Japan

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  • 学会誌年間最優秀賞

    2006.5   (社)地盤工学会  

    大塚 悟

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  • 奨励賞

    1992.5   (社)地盤工学会  

    大塚 悟

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Research Projects

  • Development of rigid plastic finite element method using nonlinear shear strength of soil material and quantitative analysis of design standard

    Grant number:18H01533

    2018.4 - 2022.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (B)

    Awarding organization:Japan Society for the Promotion of Science

    Ohtsuka Satoru

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    Grant amount:\17550000 ( Direct Cost: \13500000 、 Indirect Cost:\4050000 )

    The purpose of this study is to refine a bearing capacity analysis method and advance bearing capacity equations of rigid footing. A rigid-plastic finite element method was improved to be highly accelerated, a coupled soil-water analysis method was developed, and constitutive equations for linear and nonlinear yield functions of geomaterials were introduced. From the case study analyses of various conditions, limit load surfaces for combined vertical, horizontal, and moment loads on strip footing were formulated for base ground from cohesive to sandy and intermediate soils. The applicability of the coupled soil-water analysis to the practice was clarified by comparing the results of caisson foundation with those of centrifuge model tests under the condition where seepage forces act on the ground. For sandy soils, a bearing capacity equation was developed that takes into account the effect of footing size by modeling the internal friction angle depending on confining pressure.

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  • Is cohesive soil grounds stable even at the magnificent?

    Grant number:16H02362

    2016.4 - 2020.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (A)

    Awarding organization:Japan Society for the Promotion of Science

    Yasuhara Kazuya

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    Grant amount:\38480000 ( Direct Cost: \29600000 、 Indirect Cost:\8880000 )

    Clarification of cohesive soil behavior during and after earthquakes was achieved through field investigation, laboratory experiments, and numerical analysis, with special emphasis on earthquake-induced residual deformation, instability and post-earthquake settlements. Instability of residential foundations is accelerated by rising groundwater levels and by the increasing gradient of foundations. Even for gently sloping foundations, the importance of initial shear stress was emphasized when evaluating the severity of residual deformation of residences during earthquakes. In relation to the post-earthquake settlement, highly structured cohesive soils induce marked settlement and also prolong settlement. Results of field observations and numerical analyses proved that the combined technique of a partial embankment removal with sheet pile installation between embankments and residences was effective as a countermeasure against the instability of embankments caused by earthquakes.

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  • Study on resilience index of ground resistance for evaluation of required performance of structure

    Grant number:15K06223

    2015.4 - 2018.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    Hiroyuki Yamazaki

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    Grant amount:\4940000 ( Direct Cost: \3800000 、 Indirect Cost:\1140000 )

    From the experiences of the Great East Japan Earthquake, "resilience" of structure is required against the load exceeding the design. For the purpose of quantifying the resilience, the model shaking table test result of the caisson type revetment was analyzed by numerical calculation using finite element methods, and the relationship between the development characteristics of the seawall displacement according to the increase of the seismic load and each structural form was investigated. Furthermore, numerical analysis using rigid plastic finite element method was carried out on the results of the centrifugal model test of breakwater and revealed that it can be reasonably evaluated by conventional methods. Based on these studies the reference displacement and the reference safety factor were proposed, and it was shown that they could quantitatively express the difference in resilience due to the structural form of the caisson type revetment against the seismic load.

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  • Development of GIS based realtime evaluation method of hazard for wide-area slope collapse during heavy rain

    Grant number:25560178

    2013.4 - 2015.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Challenging Exploratory Research

    Awarding organization:Japan Society for the Promotion of Science

    SATORU Ohtsuka

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    Grant amount:\3640000 ( Direct Cost: \2800000 、 Indirect Cost:\840000 )

    In this research, a real-time risk evaluation system of surface slope failure during heavy rain was developed by using the GIS software. First, the shear strength property of soil at slope surface was investigated by reverse analysis of wide-area slope disaster by treating the disaster in 2004 Chuetsu earthquake as a full scale model test. Then, by collecting slope failure datas of 2004 and 2011 Fukushima- Niigata heavy rainfall disasters, statistical analyses of two slope disasters were carried out. Based on these results, the real-time risk evaluation model of slope failure was developed by using rainfall record in time.

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  • Seismic risk assessment of housing by using geographical information

    Grant number:22510195

    2010 - 2012

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    OHTSUKA Satoru

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    Grant amount:\4550000 ( Direct Cost: \3500000 、 Indirect Cost:\1050000 )

    For the purpose of elucidation of damage mechanism and development of disaster prediction method for housing by the earthquake, this study collected the afflicted proof of the affected houses in Chuetsu earthquake and Chuetsu-oki earthquake and analyzed for correlation with seismic intensity and house damage. By handling two earthquake damages caused by inland and coastal earthquakes, a housing damage model was investigated by excluding the locality of earthquake damage as much as possible. The housing damage ratio was introduced and employed in the correlation analysis since the number of damaged houses is not appropriate to quantitative estimation of housing damage. Finally, the relationship between housing damage ratio and seismic intensity was proposed by arranging the ground classifications into four groups

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  • Reevaluation of the seismic resistance of coastal areas in the event of large-scale serial ocean trench earthquakes, with a consideration of foundation reinforcement technologies

    Grant number:21226012

    2009.5 - 2014.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (S)

    Awarding organization:Japan Society for the Promotion of Science

    NODA Toshihiro, ASAOKA Akira, NAKANO Masaki, NAKAI Kentaro, SAWADA Yoshihiro, OHTSUKA Satoru, KODAKA Takeshi, TAKAINE Toshihiro, YAMADA Shotaro, SHIRAISHI, TAKEUCHI Hidekatsu, KAWAI Tadashi, TASHIRO Mutsumi, SAKAI Takayuki, KOMURA Seiichi, FUKUTAKE Kiyoshi, NIGORIKAWA Naohiro, NONAKA Toshihiro

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    Grant amount:\78000000 ( Direct Cost: \60000000 、 Indirect Cost:\18000000 )

    Many important infrastructures in Japan are located on the soft ground, such as Alluvial plain and coastal artificial reclaimed ground where extensive seismic damages are expected to occur. This research tries to reevaluate the seismic resistance of coastal areas in the event of large-scale serial ocean trench earthquakes with a consideration of ground reinforcement technologies. Existing damage prediction methods focus primarily on seismic stability assessment during an earthquake and are inadequate to forecast ongoing long-term ground settlement which inevitably occurs after an earthquake. To use a new numerical technology to evaluate the seismic and post-seismic resistance capabilities of natural and artificial soils in systems, in parallel with the existing methods, it will be responsible not only for a accuracy enhancement but also for preventing oversight of the serious seismic damages.

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  • Characteristics of landslides developed around Usuki-Yatsushiro Tectonic Line in Kyusyu district

    Grant number:19560503

    2007 - 2009

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    IWABE Tsukasa, OHTSUKA Satoru, ISOBEK Koichi

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    Grant amount:\2990000 ( Direct Cost: \2300000 、 Indirect Cost:\690000 )

    This study investigated the characteristics of the landslides developed around the Usuki-Yatsushiro Tectonic Line in the Kyushu district. As a result of statistical analysis of the landslide shapes, the incidence and the direction of movement of the sliding unit varied depending on its geology. The pattern of longitudinal profile of landslides changed gradually in proportion to the increase of the displacement ratio.

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  • Study on River Bank Stability Estimation Method Taking Account of Erosion Process by Overflow Water

    Grant number:19510187

    2007 - 2008

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    OHTSUKA Satoru, HOSOYAMADA Tokuzo, ISOBE Koichi

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    Grant amount:\4550000 ( Direct Cost: \3500000 、 Indirect Cost:\1050000 )

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  • A Comrehensive research on the safety evalustion of Tunnel Cosntructuion

    Grant number:18360229

    2006 - 2008

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (B)

    Awarding organization:Japan Society for the Promotion of Science

    TAMURA Takeshi, TATEYAMA Kazuyoshi, OHTSUKA Satoru, KIMURA Makoto, KISHIDA Kiyoshi, KOBAYASHI Syunichi, MASHIMO Hideto

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    Grant amount:\8180000 ( Direct Cost: \7100000 、 Indirect Cost:\1080000 )

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  • Application of Rigid-plastic Finite Element Method to Geotechnical Engineering

    Grant number:15360252

    2003 - 2005

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (B)

    Awarding organization:Japan Society for the Promotion of Science

    TAMURA Takeshi, SUMI Tetsuya, OHTSUKA Satoru, KIMURA Makoto, KISHIDA Kiyoshi, KOBAYASHI Shunichi

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    Grant amount:\6800000 ( Direct Cost: \6800000 )

    The plastic finite element method is a numerical technique for the limit analysis of structures which requires very few The programming of the rigid-plastic finiete element method is, however, a little bit more complicated than the usual finite element method. Therefore this method is not being used popularly. The main object of this research is to show the great advantages and effectiveness of the rigid-plastic finite element method by re-establishing the theoretical background and improving the computational techniques. The findings from this research are as follows.
    1)Treatment of elastic region
    In the rigid-plastic finite element method, all the region is assumed to be in plastic state, which means no elastic region exists even if it is far from loading. This assumption results in some amount of numerical error and numerical instability. Therefore it is one of the problems in the rigid-plastic finite element method to solve the treatment of elastic region. In this research, we have established the new technique for this problem by assuming the elastic region to be completely rigid without any deformation rate. This idea follows directly the theory of rigid-plasticity and can make the numerical process stable.
    2)Limit analysis of soil structure with groundwater
    It is general to assume that there exists the groundwater around the soil structures which affects the stability of ground severely. This is due to the fact that the groundwater changes the gravity force of the ground and decrease the effective stresses which makes the ground strength decreased. Therefore the treatment of the groundwater is essential to consider the limit state of the soil structures. Thus far no research cannot be found which combines the relationship between the critical state of soil structures and the effect of the groundwater in the limit state analysis. In this research, we have succeeded to combine the effect of pore water pressure as well as the change of gravity force with the equations of equilibrium at the limit state of the whole region.

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  • Study on shear strength property of re-slide type landslide and failure mechanism

    Grant number:13650538

    2001 - 2002

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    OHTSUKA Satoru, IWABE Tsukasa

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    Grant amount:\3600000 ( Direct Cost: \3600000 )

    Pore water pressure loading test on clay under constant deviator stress was conducted to investigate the behavior of landslide. From the observation on soil specimen, two threshold magnitudes in pore water pressure for deformation were obtained. One was a yield point and the other was a failure point. It was shown that the constitutive equation of sub-loading surface mode could express these threshold magnitudes through the comparison with experiments. The change in threshold magnitudes for repeats of pore water pressure loading was investigated with simulation. The failure envelopment line was drawn for failure points against the repeats of pore water pressure loading, which expressed the change process of state variable for repeated loads. The obtained failure envelopment line was examined with experiments. The existence of failure envelopment line was proved, however, the discrepancy between simulation and experiment was observed. It was pointed out to the progressive failure of soil specimen in experiment. The lost of element property in specimen was a serious problem to investigate the ideal failure stress in experiment. The detailed discussion was left to future problem. Time dependent behavior of soil specimen for pore water pressure loading was observed due to progressive failure. It suggested that the slow failure of landslide was due to progressive failure from the viewpoint of soil mechanics. The so-called second creep behavior was also measured in experiment. This phenomenon would be clarified from soil-water coupling concept. In pore water pressure loading cycle, two opposite effects were observed: one was a strain softening for increase in pore water pressure and the other was a consolidation for decrease in pore water pressure. The balance of two opposite effects much affected the soil strength of clay for repeated loads. In this study stability method for slope including the preformed slip line was also developed. Rigid plastic constitutive equation was employed.

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  • 不連続面のせん断強度特性と強度異方性を考慮した岩盤構造物の安定性評価法の開発

    Grant number:12650489

    2000 - 2001

    System name:科学研究費助成事業

    Research category:基盤研究(C)

    Awarding organization:日本学術振興会

    土居 正信, 大塚 悟

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    Grant amount:\3200000 ( Direct Cost: \3200000 )

    本研究課題に関する研究を実施した成果および今後の課題などを研究実施計画に基づいて,以下のようにまとめる.
    1.巨視的な不連続のせん断強度性を考慮した岩盤の安定解析プログラムの開発
    研究代表者および分担者は既に,塑性論におけるシェイクダウン解析の下界定理に基づく安定解析手法を開発している.岩盤特有の巨視的不連続面で発揮されるせん断強度特性(非線形な垂直応力依存性のせん断強度)を区分線形化することによって既開発プログラムに導入し,その適用性・妥当性も検証した.
    2.微細な不連続面を内包する岩盤の強度異方性を表す数値モデルの開発
    微細な亀裂を巨視的な不連続面と同様に境界値間題として取り扱うことは現実的ではなく,その特性を表現できる数値モデルの開発を試みた.しかしながら,実際の岩盤挙動を一つの数値モデルで表現できるか否かの検討および検証が今後の課題として残った.実岩盤を対象とした挙動の実験的解明も重要であることが認識された.
    3.岩盤構造物の総合的な安定解析プログラムの開発
    上記1.については実岩盤構造物への適用は十分可能である.上記2.に対する数値モデルの検証がなされれば,これを降伏関数として扱うことによって同じ既開発プログラムへの導入は容易である.
    4.既存のプログラムによる比較検討
    市販されている多くの解析プログラムは変形・応力解析を目的としたものが多く,本研究課題のように構造物の最終荷重を直接求めるものは非常に少ない.購入した弾塑性FEM解析プログラムによる解析結果と本開発プログラムによる解析結果の間には解析条件さえ同じであれば,かなりの部分で定性的な一致は見られた.しかしながら,定量的な一致は得られなかった.この原因究明も今後の課題と考えられる.

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  • Study on landslide mechanism and mechanical property of clay due to large deformation

    Grant number:11650502

    1999 - 2000

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    OHTSUKA Satoru, DOI Masanobu

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    Grant amount:\3600000 ( Direct Cost: \3600000 )

    Pore water pressure loading test on clay under constant deviator stress has been conducted to investigate the behavior of landslide. From the observation on soil specimen, two thresholds in pore water pressure for deformation were obtained. One was a yield point defined from the discrepancy from the swelling line in the void ratio and mean effective stress space. The other was a failure point where the soil specimen deforms largely and the deviator stress could not keep constant. A series of tests resulted in the yield points locating on the critical state line. At the failure point the soil specimen already got heterogeneous and deformed progressively. The soil dilated with shear due to overconsolidation and deformed with water migration. It caused the soil deformed with time for a long time. It was thought a reason for the slow failure of landslide. Numerical simulation with the Hashiguchi model well presented the soil behavior of pore water pressure loading test. It predicted the soil, which was initially overconsolidated, would get to the normally consolidated state by the repeats of pore water pressure loading. The failure point line was obtained in the void ratio and mean effective stress space for pore water pressure loading. This failure point line was empirically examined, but the effect of causes on the failure point line was still left to future stubjects. The steady state of soil after the repeats of pore water pressure loading was investigated numerically. It was found to depend on the recovery in mean effective stress. When the recovery was large, the soil would stand for larger pore water pressure loading. From the viewpoint of strain level, the ring shear test was conducted on the soil to investigate the angle for shear resistance at the residual state. The angle for shear resistance got lower with large deformation and it inspired the landslide for gentle slope.

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  • 都市社会基盤施設を支える擁壁構造物の耐震安定性評価と耐震補強に関する基礎的研究

    Grant number:11115211

    1999

    System name:科学研究費助成事業

    Research category:特定領域研究(A)

    Awarding organization:日本学術振興会

    大塚 悟, 土居 正信, 海野 隆哉

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    Grant amount:\1400000 ( Direct Cost: \1400000 )

    地震の加速度履歴や地盤・土構造物の動的特性を考慮して構造物の全体安定性を評価する手法を開発した。特に,擁壁などの人工斜面や自然斜面においては構造物のせん断強度を低減して構造物が破壊する極限状態における低減係数を用いて安全率を定義することから,研究代表者によって開発された解析手法を新たに修正・開発した。開発した手法の斜面の安定性評価への適用性を検討するために単純斜面の静的安定性について既存の解析手法と比較検討を行った。次に斜面の耐震安定性について,震度法(単一方向慣性力),震度法(慣性力の繰り返し変化の考慮),加速度履歴を考慮した解析,の3つの方法を用いて開発した手法の適用性について検討した。新しく開発した手法によると加振加速度の振動数に応じて変化する安全率が精度良く評価され,また構造物の共振による安全率の低下についても評価できることが示された。斜面の耐震安定性評価では動的変形解析によって得られた応力解を用いて静的安定解析を行うことによって耐震安定性を評価する方法があるが,この方法によると刻々と変化する安全率が得られるので全体安定性とどのような関係があるのか不明である。本研究では開発した解析手法による安全率と比較することにより,簡便解析が比較的精度の良い解を与えることを明らかにした。擁壁の地震時における土圧は変位や作用する慣性力によって様々に変化するために,擁壁を安全に保つための設計土圧は従前まで明らかでなかった。本研究では上述した解析手法を適用して擁壁の設計動土圧の評価アルゴリズムを開発した。規則・不規則波加速度に対する数値解析を通して開発した手法の適用性について検討した。

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  • Environmental Study on Underground City (Derinkuyu, Turkey)

    Grant number:09044154

    1997 - 1998

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for international Scientific Research

    Awarding organization:Japan Society for the Promotion of Science

    AYDAN Omer, KAWAMOTO Toshikazu, OTSUKA Satoru, KUNO Satoru, KATAGI Atsushi, NISHI Junji

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    Grant amount:\11000000 ( Direct Cost: \11000000 )

    Dennkuyu Underground City in Cappadocia Region of Turkey, which is unique in the world, is descending for eight floors (about 40 meters deep) beneath the ground surface and it is linked to the ground surface though inclined and vertical shafts. This underground city is presumed to had accomodated more than 10000 people and it had been used more than tousand years. In this study, we investigated the environmental, pyschological, disaster prevention and short and long term satbiity aspects of Derinkuyu Underground City to develop some guidelines for the use of underground space in modern times. We first surveyed the three-dimensional layout of the underground city and developed its geometrical model. We investigated geological, hydrogeological, seismological, archeological and rock mechanics aspects of Cappadocia Region and the close environment of Derinkuyu underground city. These investigations clarified why underground cities were stable even more than 1500 years passed over their excavations. Furthrmore, the most likely motivations for the use of underground space in Cappadocia Region are presented and discussed. The investigations on environmental aspects of Derinkuyu underground city made clear that more than 10000 people could live comfortably in this city.

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  • 都市社会基盤施設を支える地盤構造物の耐震評価と既存構造物の耐震補強に関する研究

    Grant number:08832002

    1996

    System name:科学研究費助成事業

    Research category:基盤研究(C)

    Awarding organization:日本学術振興会

    大塚 悟

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    Grant amount:\1800000 ( Direct Cost: \1800000 )

    都市社会基盤施設を支える地盤構造物の耐震安定性評価手法を新しく開発した。この方法によると,従来地震力を静的慣性力に置き換えていた方法と異なって,地震波の周期や繰り返しなどの履歴の影響の他に,荷重方向の反転による構造物の安定性低下や地盤・土構造物のダンピング特性などを考慮して構造物の安定性を評価できる特徴がある。本研究では解析手法を新たに開発すると共に,基盤で(1)正弦波加速度波,(2)不規則加速度波を与える条件の下で盛土の安定性の評価を試みた。その結果,地震波の周期による盛土の安定性の差異や,特定の周期における盛土の安定性の低下を表現することができた。この安定性の低下は盛土の共振現象に対応している。また,地盤及び盛土のダンピング特性はレーリーダンピングモデルを用いて評価したが,ダンピング特性の大きい場合には盛土の安定性は高く,また小さい場合には低く評価することができた。基盤にて不規則波を与える際の盛土の安定性についても検討を行った。
    鉄筋やジオテキスタイル等による構造物の補強が注目されているが,本研究ではこれらを線材にモデル化して解析に取り込み,配置や強度,曲げ剛性等の耐震補強効果に与える影響について数値解析を用いて各種の検討を行った。その結果,これらの線材による補強効果は無補強に対して確かに認められるものの,劇的な補強効果は見られなかった。盛土のり面においてフェーシングを施す方法と補強材とを結合して用いる補強を行うと,補強効果がかなり大きく得られ,このような施工が耐震安定性の向上には必要であることを明らかにした。

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  • Residual deformation assessment of earth structure against earthquake and its application for design

    Grant number:07455190

    1995 - 1996

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (B)

    Awarding organization:Japan Society for the Promotion of Science

    MATSUO Minoru, NAKANO Masaki, OHTSUKA Satoru

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    Grant amount:\6700000 ( Direct Cost: \6700000 )

    This study presents new stability methods of earth structures against earthquakes and rigid-plastic dynamic deformation analysis, and discusses their applicability in practice.
    1. Consideration on safety factor of earth structure against earthquakes
    A new stability method based on the shakedown theory considers the acceleration time history of earthquake exactly. The applicability of this method is examined for both sine and irregular acceleration waves enforced at the bedrock. The conclusions in this study were as follows : 1) The effects of periods in enforced accelerations on embankment stability were suitably evaluated. The stability depended on not only the enforced acceleration, but also the dynamic properties of the ground. 2) The applicability of new method is discussed in comparison with the conventional seismic coefficient method.
    2. Development of rigid-plastic dynamic deformation analysis
    The dynamic deformation analysis based on rigid-plastic assumption was developed in purpose of residual deformation assessment of earth structure against earthquakes. The results obtained in this study were as follows : 1) THe rigid-plastic dynamic deformation analysis could simulate the behavior of the geotechnical structures properly which changes their states between rigid body and plastic flow. 2) With the use of the stress history model of clays for repeated loads, the liquifaction process of plane strain repeated test was fairly simulated by rigid-plastic dynamic deformation analysis.

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  • Stucy of Liquefaction Protection of Ground Supporting Infrastractures

    Grant number:06555138

    1994 - 1995

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Developmental Scientific Research (B)

    Awarding organization:Japan Society for the Promotion of Science

    MATSUO Minoru, SUZUKI Y, NAKANO M, OHTSUKA S, KANATANI Y, UENO M

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    Grant amount:\1100000 ( Direct Cost: \1100000 )

    This sutdy developed two methods to evaluate the stability of soil structures. One is a stability analysis which deals with the limit state of structures and the other is a dynamic deformation analysis to examine the residual deformation of structures against earthquakes. In stability analysis, a new safety concept is proposed against dynamic loads and shown to give rational factors of safety through some numerical examples. It could consider the effect of acceleration time history of earthquakes. On the other hand, in dynamic deformation analysis rigid perfectly plastic assumption is employed. It is exhibited to yield good solutions for large deformation problems. The effect of geometrically change of structures on the deformation is discussed. For liquefaction problems, an excess pore water model for earthquake is introduced after Carter et al.. The liquefaction process is well simulated with this method.

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  • 建設残土を利用した改良地盤の特性とその設計法に関する研究

    Grant number:06838003

    1994

    System name:科学研究費助成事業

    Research category:一般研究(C)

    Awarding organization:日本学術振興会

    松尾 稔, 中野 正樹, 大塚 悟

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    Grant amount:\2000000 ( Direct Cost: \2000000 )

    本研究では砂に代わって建設残土を用いる新しい地盤改良工法を開発を目指している。今年度行った研究の成果を以下に示す。
    1.まず,建設残土の性質に応じて、4種類の地盤改良の施工方法を提案した。すなわち、(1)砂や第1種建設発生土(建設省により分類されたもの)に対して、従来のSCP施工と同じ工法、(2)第1、2種や石炭灰の加工したものに対して、SCP施工と周辺土にプラスチックドレーン(PD)を併用、(3)第2、3種では、SDP施工が不可能となり、ドレーン施工とPDの併用、(4)第3、4種に対して(3)ほとんどおなじ施工方法である。
    2.残土杭打設過程には水-土骨格連成極限つり合い解析を、一時的破壊後の再圧密過程には弾塑性圧密変形解析を用いて破壊後の圧密効果および支持力増加特性を調べた。バイブロによるケーシング打ち込みと打ち戻しによる砂杭経拡幅と締め固めを行う「SCP施工」では、周辺地盤の強度は拡幅後、圧密することによって、かなり上昇した。
    3.実際に、砂杭打設を想定した室内貫入試験を行った。その結果、打設後、周辺粘土の過剰間隙水圧は上昇することがわかった。さらに、貫入後の含水比を測定したところ、貫入前よりも小さくなっていて、載荷することにより、さらに含水比は小さくなった。このことは、砂杭打設によって周辺の粘土の強度が上昇することを意味する。すなわち、2.の計算を実証することができた。
    4.1.の(3)、(4)に対して、排水を助けるためのPDの効果を調べるため、3.の室内貫入試験の貫入棒の周りにPDを入れた。その結果、PDが多くなるほど、圧密時間は短くなることがわかった。

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  • 剛塑性動的変形解析に基づくN値の力学的考察と動圧密工法の解析的研究

    Grant number:06805042

    1994

    System name:科学研究費助成事業

    Research category:一般研究(C)

    Awarding organization:日本学術振興会

    大塚 悟, 中野 正樹, 松尾 稔

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    Grant amount:\2100000 ( Direct Cost: \2100000 )

    Martinの塑性定理に基づいて、標準貫入試験の変位量を推測する方法を与えた。具体的事例に標準貫入試験を採用したが、地表面に物体の落下を与えれば動圧密工法における運動メカニズムと全く変わらない。ここでは標準貫入試験を重錘の落下による衝撃問題と捕らえて、運動量の等価な変位速度を地盤に与えて物体の落下による最終変形量を算出する。最終変形量は地盤の塑性エネルギーの消散から与えられる。地盤を粘性土の様なMises材料と、砂質土の様なDrucker-Prager材料に理想化して、地盤深さとN値との関係を数値解析を用いて求めた。その結果、従来提案されている実験公式と比較的良く似た傾向を得ることができた。しかし、実際の標準貫入試験ではサンプラーの機構を兼ね備えているために、数値解析で用いた地盤の初期変位速度に関する等変位速度条件は実際問題を過度にモデル化しているために、解析結果の妥当性や適用性については若干問題が残されている。その点ではN値を求める方法については従来のような標準貫入試験ではなく、むしろサンプラーの機能を捨てて、もっと単純な条件での試験を行うことが、N値自身の土の物性評価力を上げることになると思われる。重錘落下工法に本方法を適用するためには、重錘落下によって生じる地盤の過剰間隙水圧分布の算出が必要になる。本研究ではカムクレイモデルを用いて破壊時有効応力分布の算出を行って過剰間隙水圧分布を算出した。地盤の応力は衝撃力と運動によって刻々と変化するが、境界値問題に固有なモードに到達すると、そのモードのまま変形が収束する性質を用いて固有モードにおける地盤内応力を算出し、過剰間隙水圧算出に成功した。今後は得られた過剰水圧分布の消散に基づく地盤の強度上昇量の評価について実施する予定である。

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  • Stability evaluation of soil structure for earthquake taking acceleration time history into consideration

    Grant number:04452225

    1992 - 1993

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for General Scientific Research (B)

    Awarding organization:Japan Society for the Promotion of Science

    MATSUO Minoru, KODAKA Takeshi, NAKANO Masaki, OHTSUKA Satoru, ASAOKA Akira

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    Grant amount:\5800000 ( Direct Cost: \5800000 )

    This study focuses on two topics. One is stability evaluation of soil structure for dynamic loading as earthquake. The other is evaluation on residual deformation of soil structure caused by dynamic loading.
    The seismic coefficient method has been employed to estimate a stability of soil structure for a dynamic load the direction and the magnitude of which vary in time. But, it can not consider an acceleration time history of an earthquake and dynamic properties of both soil structure and ground. This study presents a new analytical method to estimate a stability of soil structure for a dynamic loading as an earthquake taking acceleration time history into account. The applicability of this method to design is discussed.
    On the other hand, rigid plastic dynamic deformation analysis is developed to evaluate a residual deformation by an earthquake loading. In a rigid plastic assumption displacement is generally in determinate. It is, however, rationally determinate in concern with a prescribed acceleration on the boundary. Typical numerical examples are shown for embankment problems under earthquakes.

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  • 土構造物の時間的な安定性の低下を考慮した降雨・地震荷重に対する安定解析

    Grant number:03650402

    1991

    System name:科学研究費助成事業

    Research category:一般研究(C)

    Awarding organization:日本学術振興会

    松尾 稔, 菅井 径世, 鈴木 康弘, 大塚 悟, 浅岡 顕

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    Grant amount:\2100000 ( Direct Cost: \2100000 )

    鉄道や高速道路などに代表される大量交通機関を支える斜面・土構造物の降雨や地震、および交通荷重に対する繰り返し荷重に対する安定性を評価する方法論の開発を目的に研究を実施した。このような問題は従来よく取り扱われてきた、支持力問題や斜面安定問題などのいわゆる単調載荷問題とは異なって、これらの外的要因の繰り返しによる残留変形量の蓄積などによる構造破壊が問題となる点に特徴がある。斜面や土構造物の経時劣化の評価とその維持管理への応用が本研究の最終目標である。研究代表者らは降雨による斜面の経時的な安定性の劣化についてその方法論を開発してきており、本研究では繰の返し荷重を受ける土構造物の安定性を適切に評価する解析手法の開発を中心に研究を行なった。交通荷重などの繰り返し載荷も静的荷重の繰り返しと捉えると解析は比較的簡単になる。Sakedown解析による土構造物の解析はこれらの静的荷重の方向や大きさが変化したり、また繰り返し載荷する場合にも容易に解析することが可能である。ところが、地域荷重のように動的な載荷の場合には従来の静的荷重に対する解析では取り扱うことが出来ず、以前として問題は解決されない。物体力を静問荷重に置き換えて土構造物の安定性を評価する静的震度法が従来このような問題に対する解析手法として用いられてきたが、この方法は地域の最大加速度を考慮するものの、地域加速度の方向や加速度の変化、地震加速度の周期、土構造物の振動特性等を全く考慮できない問題点があった。本研究ではShakedown解析を拡張することにより、これらの影響を正当に評価できる方法論を開発し、数値解析を通して地震荷重と土構造物の振動特性による安定性の差異について検討し、解析手法の妥当性について考察した。
    今後はこれらの個々のサブシステムを統合して総合的な安定性評価手法の開発を行なう予定である。

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  • 静的および繰り返し的に作用する浸透力による砂質地盤離の破壊機構の研究

    Grant number:03650401

    1991

    System name:科学研究費助成事業

    Research category:一般研究(C)

    Awarding organization:日本学術振興会

    浅岡 顕, 菅井 径世, 鈴木 康弘, 大塚 悟

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    Grant amount:\2000000 ( Direct Cost: \2000000 )

    砂質地盤からなる海岸防波堤マウンドの潮力、波力等の繰り返しによる経年劣化と破壊機構の解明を目本に砂質地盤の浸透破壊のメカニズムについて実験的検討を行なった。本研究では砂質地盤中に矢板を打設し、一方から水を浸透させて地盤を破壊させる実験を行なった。この問題における限界水位高さにはTerzaghiによる解法があるが、水位高さの上昇速度や地盤のせん断強さなどの項目が無視されているなどの問題がある。本研究ではこの水位上昇速度を変化させて、限界水位に及ぼす透水係数や荷重履歴の影響について検討した。載荷速度による室内せん断試験にはBishopによる正規圧密・過圧密粘土三軸供試体の非排水・排水せん断試験が著名であるが、本研究においても室内モデル実験を用いてこれらの条件に反応する実験を試みた。試料には粘土でいうところの正規圧密と過圧密試料を想定した密詰め砂と緩詰め砂を用いて、急速載荷・超緩速載荷によってそれぞれ非排水と排水条件をシミュレ-トした。この結果、地盤条件が同じでも載荷条件によって地盤の限界水位高さは随分異なることが明らかになった。
    他方、土の構成式を用いた極限釣り合い解析手法によって、この実験の解析を試みた。急速載荷の場合には水位上昇速度が排水より著しく速いために地盤が殆ど非排水的な挙本となることから、解析は実験値と非常に良い対応を示した。それに対して超緩速載荷の場合には地盤が緩い砂質土の場合には比較的良く解析値と一致するものの、密詰め砂の場合には、過圧密粘土の排水試験時に発生しやすいひずみ軟化挙動のため解析不可能であった。これらの一連の実験および解析を通して浸透破壊問題の解析手法を示すと共に、解析手法の限界を明らかにした。なお、浸透実験では気泡の発生が破壊に著しく関与する事実を発見しており、今後この気泡の発生と破壊の進展について研究を進めていく予定である。

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  • Soft Soil Improvement by Vertical Sand piles

    Grant number:02555110

    1990 - 1991

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Developmental Scientific Research (B)

    Awarding organization:Japan Society for the Promotion of Science

    MATSUO Minoru, KANATANI Yoshihisa, OHTSUKA Satoru, ASAOKA Akira

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    Grant amount:\4600000 ( Direct Cost: \4600000 )

    Sand Drains
    (1)The range of soil permeability which yields the variation of partial drain behavior was found
    10^<-7>cm/sec k 10^<-4>cm/sec
    when a clay deposit of about 25 meters thick is considered.
    (2)When soil permeability lies on this particular range the bigger the load intensity, the more the partial drain effect should be expected.
    (3)The efficiency of sand drains is to be observed in a limited range of soil permeability and under a particular magnitude of load intensity.
    2. Sand Compaction Piles
    (1)The bearing capacity of soft clay with vertical sand compaction piles is extremely influenced by the stiffness of applied load. When load application through a rigid
    footing is considered fully drained/swelling conditions for sand piles provide bigger
    bearing capacity than undrained/no swelling conditions. On the other hand, when
    flexible load application such as embankment loading is the case, undrained conditions
    give bigger bearing capacity than fully drained/swelling condition.
    (2)The increase of the undrained strength of clay due to displacement and consolidation by sand pile installation should be correctly evaluated when relatively low sand replacement ratio is considered.

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  • 海上造成地盤の支持力・変形予測システムの最適化に関する研究

    Grant number:01460178

    1989 - 1990

    System name:科学研究費助成事業

    Research category:一般研究(B)

    Awarding organization:日本学術振興会

    松尾 稔, 大塚 悟, 馬場 俊介, 浅岡 顕

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    Grant amount:\4500000 ( Direct Cost: \4500000 )

    海底超軟弱地盤に大規模な土地造成を行う際の設計のための最適な支持力・変形の予測システムの開発を目的に研究を実施した。本研究の特徴は事前設計の開発だけでなく、本工事の一部、または試験盛土の観測結果を用いて設計・施工を変更する動学的設計システムを構築する点にある。以下に、本研究で得られた成果を箇条書きにする。
    (1)圧密を考慮した軟弱地盤の支持力評価手法の開発
    (2)原地盤と同様に部分的な排水を伴いながらせん断する部分排水実験を実施し、(1)の手法の適用性について実験的に実証した。また、解析に必要な各種土質パラメ-タの決定方法についても考察している。
    (3)弾塑性理論に基づき、軟弱地盤上に盛土を構築する際の地盤の支持力・変形特性について詳細に調べた。地盤の挙動は載荷速度や上載荷重の大きさによって随分異なる挙動を示す。
    (4)(3)の解析では観測される沈下量から算定される圧密速度と支持力の増加速度を比較し、両者が良く一致する傾向のあることが分った。
    (5)本工事の一部または試験盛土の観測を用いた施工管理には、最終沈下量の予測には自己回帰モデルによる予測手法が、また安定性の評価には、松尾・川村の方法や接線骨格変形係数の劣化過程の追跡による破壊予測法が適用できる。
    (6)盛土の動学的設計は事前設計と本工事の一部または試験盛土の観測と(5)による施工管理、そして(3)、(4)による地盤安定性の確認と変形量の予測に基づく設計の確認やチェックボ-リングによる調査を用いた設計変更により行われる。

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  • 浸透力による地盤破壊の理論的および実験的研究

    Grant number:01550383

    1989

    System name:科学研究費助成事業

    Research category:一般研究(C)

    Awarding organization:日本学術振興会

    浅岡 顕, 大塚 悟

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    Grant amount:\2100000 ( Direct Cost: \2100000 )

    飽和地盤の支持力・安定解析は、近年、間隙水圧と変位速度場を連成させて極限釣合い式を解く手法の開発によって、新たに実際的な応用の範囲を広げている。本研究では更に、浸透力による地盤の多次元的な破壊の問題(砂質地盤中の締切り矢板の下を回る浸透力による破壊)を取り上げ、解析方法の確立とともに模型実験による現象の把握・検証を試みた。以下に、本研究で得られた結論を箇条書きにする。
    (1)砂は詰め方により単位体積重量が異なる。本研究では常に所定の単位体積重量となる模型砂質地盤の作成方法を確立し、緩い地盤・密な地盤に対して浸透破壊実験を行った。
    試料には豊浦標準砂および愛知県知多半島で採取される野間砂を用いたが、上述の模型地盤において豊浦砂は詰め方に依らず常に過圧密的な挙動を示し、他方、野間砂は緩詰めの際には正規圧密的、密詰めの際には若干過圧密的な挙動を示すことを各種の力学試験より明らかにした。
    (2)浸透破壊実験では矢板の根入れが深いと破壊に至るまでに大きな変形を生じるのに対して、根入れが浅いとボイリングの生じるまでにはほとんど変形が生ぜず、急速に全般破壊を生じる結果が得られた。
    (3)限界水位高さは従来のTerzaghiの方法によると、載荷速度によらず一意的に決定されたが、実験では載荷速度の依存性が現れる。
    (4)浸透力による砂質地盤の安定解析手法を提案し、非排水および排水条件で数値解析を行った。得られた限界水位高さは排水条件によって異なり、(3)の実験結果を裏付けた。載荷速度の大きい非排水条件の場合には実験と解析結果には若干の差異がみられるが、正規地盤と見做すことが出来る排水条件の場合には実験結果と非常によく一致した。

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  • 地盤補強型深礎基礎の設計および施工法の開発

    Grant number:63850113

    1988 - 1989

    System name:科学研究費助成事業

    Research category:試験研究

    Awarding organization:日本学術振興会

    松尾 稔, 上野 誠, 鈴木 壽, 大塚 悟, 浅岡 顕, 正垣 孝晴

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    Grant amount:\7400000 ( Direct Cost: \7400000 )

    本年度の研究目的は、深礎基礎体の縮小化を図ることが期待できる地盤補強型深礎基礎の耐力評価式と施工技術を確立することにある。実務への適用を前にした本研究では、(1)実規模大現場実験を行い、小型模型実験、中規模模型実験で得られた知見の確認をし、補強効果のメカニズムの確認を行い、それを基にした(2)モデル化により補強効果を考慮した(3)設計法を確立した。また、(4)現場施工実験を行い、効率的な施工方法を確立した。以下、研究成果を箇条書きにする。
    (1)実規模大現場実験では実大基礎(直径:3m、長さ12m程度を想定)の1/2の基礎体を用いて、砂質土系地盤で、補強材打設方向をパラメ-タとした鉛直引上げ載荷実験を行った。実験では中規模現場実験と同じ項目の計測を行った。地盤・基礎体・補強材の挙動は中規模現場実験の挙動と同様な傾向にあり、補強効果(降伏荷重、終局荷重の増加量)も無補強基礎に比して、1.3〜2.2倍程度と同等の効果が期待できた。
    (2)前年度の研究成果で明らかになった構造効果、補強土効果による評価モデルを設定し、補強効果の分析を行った結果、降伏荷重レベルまで同一変位における荷重の実験値と評価値が概ね一致し、評価法の妥当性が検証された。また、終局荷重状態においても地盤の円筒形せん断面における地盤や補強材に作用する力の釣合いより評価した極限支持力は実験値と比較し、工学的にみて十分な精度をもつと判断された。
    (3)補強効果モデルを基にした設計方法を確立した。実用的で効果的な補強材配置を選定し、そのときの補強効果を評価できる設計法である。
    (4)深礎基礎の基礎部分の掘削時における補強材孔(φ10cm)を穿孔する穿孔機械の開発を行い、実規模大の模擬施工(施工実験)を行った。小型かつ軽量な資機材で、迅速かつ確実な補強材の打設・定着を行える結果を得、効率的な施工方法を確立した。

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  • 山岳高速道路隣接のり面の豪雨時崩壊予測システムの構成とその実証的研究

    Grant number:63601516

    1988

    System name:科学研究費助成事業

    Research category:重点領域研究

    Awarding organization:日本学術振興会

    松尾 稔, 大塚 悟, 鈴木 壽, 浅岡 顕

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    Grant amount:\2000000 ( Direct Cost: \2000000 )

    本研究は以下の2段階的な研究を総合し、高速道路に隣接する危険のり面について豪雨時の崩壊予測に至る実際的な研究を行った。
    1 統計的決定理論によるのり面危険度判定と「要管理のり面」の抽出
    中央道多治見〜諏訪間に限ってもおよそ380もののり面が存在し、個々ののり面について2にて後述する厳密な地質力学的逆解析は実施することはできない。そこでこのうちどののり面が最も監視・管理を要するのかを、のり面諸性質(地質・幾何構造・水理条件・土質条件)と崩壊履歴との間の統計法則を導き、統計的方法により抽出する。統計的決定理論によると、(1)判定のための評価基準は何か、(2)因果関係(崩壊メカニズム)の推定、(3)統計データの質の判断、(4)決定(判定)に至る論理、を峻別してとらえ、(1)〜(3)のどのような要求に対しても対応することができる。
    2 刻々の降雨データを用いる危険のり面の安定解析と崩壊予測
    1で抽出された危険のり面に対して、地質・幾何形状の調査および各種の土質試験を行い、過去の崩壊事例に対して豪雨時の斜面安定解析を行った。その際に1次元飽和〜不飽和浸透解析と円弧・直線すべり法による豪雨時の斜面崩壊解析手法を開発している。
    本解析法の特徴は飽和・不飽和浸透解析に必要な土質諸定数および地盤内強度分布など未知パラメータを過去のそののり面の降雨時挙動を説明するように逆解析を通じて定める点にある。この方法によると、従来考慮することのできなかった、(1)のり面のコンクリート吹付およびのり枠の有無、(2)風化の程度、(3)涌水の有無などの要因についても考慮することが可能になる。のり面の崩壊は破壊確率の急上昇を用いて判定したが、その結果は過去の崩壊事例をよく説明することができる。

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  • 信頼性理論に基づく杭の設計用支持力評価法に関する研究

    Grant number:63550361

    1988

    System name:科学研究費助成事業

    Research category:一般研究(C)

    Awarding organization:日本学術振興会

    松尾 稔, 大塚 悟, 鈴木 壽, 浅岡 顕

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    Grant amount:\2100000 ( Direct Cost: \2100000 )

    本研究は杭の支持力に関する力学的な解明と実務設計を念頭においた支持力評価法の開発を行うために、(1)載荷試験データに基づく極限支持力推定法の提案、(2)既存データの整理による静的支持力式の開発、および、(3)より精度の高い動的支持力式の開発とそれを用いた信頼性理論による打ち止め管理システムの開発、を試みている。
    (1)載荷試験データを用いた極限支持力の推定は従来、載荷試験データが破壊近傍まで与えられないと十分な精度で支持力を予測することは非常に難しい。本研究では、杭頭での荷重〜変形関係だけでなく荷重〜残留沈下関係を用いた極限荷重推定法を開発し、既存データの解析から本解析法の妥当性について検討した。本手法を用いると従来法に較べて極めて高精度に極限荷重を予測することが可能になる。
    (2)既存静的支持力式の考察に基づき、数多くの載荷試験データの統計的な解析から先端支持力と周面摩擦との分離を可能とする新しい静的支持力式を提案し、その工学的有用性を従来法との比較を用いて検証した。
    (1)、(2)については現在、その研究をとりまとめて土木学会論文集に投稿中である。
    (3)打ち込み時の杭の挙動を一次元波動方程式で記述し地盤の動的支持力を推定する方法を新しく提案した。本手法は光学式変位形を用いて杭頭波形を高精度にしかも比較的簡便に測定することが可能になったことに着目して、測定された杭頭波形を境界条件に用いて一次元波動方程式を厳密に解く方法である。載荷試験との比較による本解析法の妥当性についても検討した。研究成果は土質工学会による杭の打ち込み性および波動理論の杭への応用に関するシンポジウム論文集にて発表している。
    本研究では信頼性理論に基づく杭の打ち止め管理システムの開発を行っているが、サブシステムを含めて今後の研究が必要である。

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  • 若干過圧密な自然堆積粘土地盤の支持力・安定解析に関する研究

    Grant number:62550359

    1987

    System name:科学研究費助成事業

    Research category:一般研究(C)

    Awarding organization:日本学術振興会

    浅岡 顕, 大塚 悟, 正垣 孝晴, 鈴木 壽, 松尾 稔

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    Grant amount:\1400000 ( Direct Cost: \1400000 )

    本研究は, 若干過圧密である事が多い沖積粘土地盤上での盛土施工の安定性の検討(極限荷重の計算)を目的に, (a)部分排水三軸試験を用いた自然堆積粘土の挙動の解明, (b)荷重履歴を考慮した支持力の算定, (c)施工中の観測を用いた極限荷重の予測, に対する系統的な研究を行った. 以下に, 本研究で得られた成果を要約する.
    (1)練り返し粘土および自然堆積粘土の非排水試験を行い, 構成式(Cam clayモデル, 関口・太田モデル)の適用性について検討した. その結果, 間隙水圧〜軸ひずみ関係は構成式によって比較的良く表現されるが, 軸差応力〜軸ひずみ関係を同時に記述することは難しいこと, しかし(非排水)強度については弾塑性パラメータを巧く選ぶことで十分に表現することができること, が明らかになった.
    (2)粘土の構成式は硬化パラメータを塑性体積ひずみにとることが多く, 構成式から得られる非排水条件を用いて荷重履歴を考慮した非排水支持力を算定することができる. 軟弱地盤上の盛土, および部分排水三軸試験の数値シミュレーションを行い, 載荷速度, 載荷荷重の影響について検討した. 載荷速度の大きいほど残留変形は大きくなるが, 載荷荷重が非排水支持力に対して安全率で1.1以上の場合には載荷速度の影響が殆ど表れないことが明らかになった. この傾向は正規圧密, 地表面過圧密, および全体過圧密地盤で変わらない. 他方, 三軸試験による部分排水強度については予測値と実験値が良く一致し(b)の方法の妥当性が検証されたが, 漸増載荷の後に荷重一定で放置するような場合にはシュミレーションと実験には軸ひずみの発生に差異があり, 上述(1)と共に構成式に関する課題が残された.
    (3)荷重〜時間〜変形関係を用いた極限荷重予測法に, 骨格変形係数の劣化過程の追跡による方法がある. この場合には一切土質パラメータは必要ない. しかし過圧密地盤では適用に際して十分な注意が必要であることが指摘された.

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  • 統計的決定理論によるのり面危険度判定の支援システムに関する基礎的研究

    Grant number:62550358

    1987

    System name:科学研究費助成事業

    Research category:一般研究(C)

    Awarding organization:日本学術振興会

    松尾 稔, 大塚 悟, 正垣 孝晴, 鈴木 壽, 浅岡 顕

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    Grant amount:\2100000 ( Direct Cost: \2100000 )

    本研究は道路公団中央自動車道の多治見〜諏訪間のような山岳切り取りのり面の安全性の評価を, 単に土質力学的な視点から究明するものではなく, 既往のり面の崩壊・未崩壊事例に基づいて素因の分析とそのデータベースに基づき, 対象のり面の危険度判定を行うための統計的決定理論による意思決定支援システムを構成したものである. 本研究の成果を要約すると以下のようである.
    (1)中央自動車道のり面・斜面の崩壊・未崩壊事例の収集・整理を行った. その結果, 斜面崩壊の形態はすべり面が高々1〜2mの浅いものが多く, のり面保護は植生である場合に崩壊が多いこと, 連続雨量では100〜200mm, 最大時間雨量は20〜40mm程度であることを明らかにした.
    (2)飽和・不飽和浸透解析を基礎とした降雨時の斜面安定解析法による事例解析を実施するために, 崩壊履歴のある斜面において現位置土質調査と不攪乱土質試験の室内試験を実施した. 不飽和土の強度係数を求めるために三軸圧縮試験を排気・排水条件別に実施し, それらの強度差を明らかにした.
    (3)(2)で得られた各種入力データに基づいた事例解析を実施した. その結果降雨時の斜面安定解析法に用いるべき強度試験法としては, 排気・非排水試験で十分であること, ひずみレベルによる不飽和土の強度差は解析結果にあまり影響しないことが明らかとなった. また, 各種入力パラメータの安全率の絶対値に与える影響が大きいので, 安全率の低下速度に着目した方法も検討した. この方法によれば, 一般に知ることが困難である地盤内の初期飽和度などの影響にあまり依存されず, 崩壊発生時で指摘することができる.
    なお, これらの解析と多数収集・整理された崩壊・非崩壊データに基づきのり面危険度判定の支援システムを開発中である.

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