| Project/Area Number |
16K06500
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Geotechnical engineering
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| Research Institution | Kochi National College of Technology |
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Principal Investigator |
OKABAYASHI Kojiro 高知工業高等専門学校, ソーシャルデザイン工学科, 教授 (70185461)
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| Project Period (FY) |
2016-10-21 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000)
Fiscal Year 2018: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2017: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Fiscal Year 2016: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
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| Keywords | 液状化 / 動的一面せん断試験 / 南海トラフ巨大地震 / 地盤の残留強度 / 地震応答解析 / 遠心力模型実験 / 逐次非線形解析 / 南海地震 |
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| Outline of Final Research Achievements |
The Cyclic Box Shear Test Machine installed at Kochi KOSEN has been improved in accuracy to make it possible to carry out a liquefaction strength test. The effects of shear box inclination and constant volume conditions were also examined to determine appropriate test methods. The liquefaction strength tests were carried out at relative densities of 30% and 50%. Moreover, the validity of the liquefaction strength test was verified in comparison with the cyclic triaxial test using the same material. Furthermore, with regard to residual strength after cyclic testing, experiments were conducted using cyclic stress amplitude ratio as a parameter to examine the influence of dilatancy.
The liquefaction strength obtained in the test was applied to seismic response analysis by effective stress method and centrifugal model test. It was confirmed that it could be used for examination of liquefaction prevention construction method of river embankment and fishing port wharf.
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| Academic Significance and Societal Importance of the Research Achievements |
東日本大震災では、東北から関東にかけての広範囲で地盤の液状化が発生し、埋め立地盤や河川堤防などが甚大な被害を受けた。高知県でも「南海トラフ巨大地震対策」として最大クラスの地震動を想定した検討がなされている。地盤構造物も地震や地盤の液状化に対して粘り強い構造とすることが望まれる。
本研究では、繰返し一面せん断試験装置を開発し液状化強度試験が高精度で実施できる装置とする。次に、地震動の継続時間と地盤の粘り強さに着目して、繰返し載荷回数に対する地盤の残留強度の動的せん断試験法を提案する。また、得られた結果が動的有限要素解析や遠心力模型実験にも適用できることを検証する。
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