Mechanism of progressive failure in river dike during infiltration and overflow and its prediction
| Project/Area Number |
17560441
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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 | Tohoku University |
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Principal Investigator |
UZUOKA Ryosuke Tohoku University, Tohoku University, Graduate School of Engineering, Associate Professor (40333306)
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| Co-Investigator(Kenkyū-buntansha) |
SENTO Noriaki Tohoku University, Graduate School of Engineering, Assistant Professor (40333835)
IZUMI Norihiro Hokkaido University, Graduate School of Engineering, Professor (10260530)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,850,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥450,000)
Fiscal Year 2007: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2006: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2005: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | geotechnical engineering / land protection / flood / disaster reduction / disaster prevention / river dike / infiltration / progressive failure |
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| Research Abstract |
The purpose of this study is to clarify the mechanism of progressive failure of river dike during the infiltration and overflow of river water. First, infiltration-shear tests during of unsaturated soil from actual river dike were performed in order to propose a constitutive model which can reproduce shear deformation during infiltration. As the results of the infiltration-shear tests, large shear strain was produced during infiltration under initial shear condition. An elasto-plastic constitutive model was newly proposed to reproduce the results of the infiltration-shear tests. The proposed constitutive model is based on super/sub loading surface Cam-Clay model and it has a modified evolution law which is a function of suction as an internal variable. The proposed model reproduced the increase in large shear strain during infiltration in the simulation of the infiltration-shear tests. Second, dynamic soil-water-air coupled analysis method at finite strain was developed. Static self-weight analyses, quasi-static consolidation analyses, dynamic consolidation analyses and quasi-static leaking flow analyses of unsaturated soil were performed in order to verify the developed numerical code. Preliminary analyses with elastic constitutive model showed that the proposed "aerial element" which has water retention characteristics of air and small stiffness could be used for direct modeling of river water. Although further investigations into convection term are needed, aerial element can be useful for the interaction analysis between overflow water and soil embankment. Third, progressive failure of river dike during infiltration of river water was simulated with the proposed constitutive model and numerical code. Although further investigations into implicit integration of stress are needed, the numerical results showed that seepage flow appeared at the landside toe of the dike and the slope became unstable at the waterside toe of the dike when the river level rose.
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Report
(4 results)
Research Products
(10 results)
