| Project/Area Number |
07650562
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Geotechnical engineering
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| Research Institution | Ibaraki University |
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Principal Investigator |
YASUHARA Kazuya Ibaraki University, Faculty of Engineering, Department of Urban and Civil Engineering, Professor, 工学部, 教授 (20069826)
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| Co-Investigator(Kenkyū-buntansha) |
MURAKAMI Satoshi Ibaraki University, Faculty of Engineering, Research Assistant, 工学部, 助手 (10261744)
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| Project Period (FY) |
1995 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1997: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1996: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1995: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Earthquake, / Cohesive soil, / Cyclic loading, / River dyke, / Residual deformation, / Instability / 側方流動 |
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| Research Abstract |
Based on the results from laboratory investigation using cyclic and direct-simple shear tests on clays and their consideration into modeling for numerical analysis of behavior of embankments on soft ground, the following is pointed out :
l) Degradation of stiffness and strength of cohesive soils triggered by undrained cyclic loading in triaxial conditions can be uniquely correlated to the magnitude of shear strain observed during cyclic loading. This is common with normally consolidated and overconsolidated specimens.
2) Numerical analysis using a computer program for dynamic response analysis called SADAP incorporating the above-mentioned finding was carried out to obtain the design chart for predicting the earthquake-induced settlements as a parameter of the maximum acceleration and the overconsolidation ratio (OCR). A practical availability of the design chart was proved by comparing with the settlements observed in the results of centrifuge tests on the river dyke founded on soft clay.
3) The results from numerical analysis were also given in the from of the design chart to forecast whether the dyke or the ground leads to instability during earthquakes.
4) Through the results not only from the numerical analysis but also from the centrifuge tests, the effectiveness of preloading or surcharging was recognized as a countermeasure for increasing the stability of river dykes founded on soft clay.
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