2003 Fiscal Year Final Research Report Summary
Numerical Analysis for Seepage, Transportation and Collapse in Geo-Environmental problems using micro processors
| Project/Area Number |
13660239
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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 |
Irrigation, drainage and rural engineering/Rural planning
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| Research Institution | The University of Tokyo |
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Principal Investigator |
TANAKA Tadatsugu The University of Tokyo, Graduate School of Agricultural and Life Sciences, Professor, 大学院・農学生命科学研究科, 教授 (70167500)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAI Kazuhito University of Ryukyus, Department of Agricultural Production Environments, Associate Professor, 農学部, 助教授 (10253949)
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| Project Period (FY) |
2001 – 2003
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| Keywords | Seepage / Nonlinear Analysis / Finite Element Method / Elasto-Plastic Constitutive Model / Cyclic Loading / Dynamic Response Analysis |
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| Research Abstract |
The solutions of boundary value problems involving strain-softening material property are full of serious difficulties from both modeling of strain-localization and a viewpoint of numerical procedure. Mesh size-dependent softening modulus is considered to alleviate the mesh size-dependency of the solution. The soil model is based on experimental findings about inherent and induced anisotropies involved in sand. The results of finite element analysis are compared with those from the physical experiments.
The dynamic relaxation method with implicit-explicit type is effective for soil-structure interaction problems and suite for the parallel computations. The explicit method without stiffness matrix is applied to parts of soil mass and the implicit method is used to a part of the stiff structures such as retaining wall, therefore two methods are used simultaneously. Seepage failure have initiated by the rise of a soil layer adjoining the down stream toe of the hydraulic structure. A failur
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e of this kind was often investigated by a model experiment of single-wall sheet-pile. We investigated the problem by a model experiment and finite element analysis. The observed hydraulic head at collapse was simulated well by the finite element analysis employing elasto-plastic constitutive equation.
The elasto-plastic constitutive soil model is applied to the analysis of direct shear tests and slope failure model experiments. Two-and three-dimensional analyses were performed and good agreement with an experiment was obtained. Moreover, in the analysis of a footing load experiment on a wet, slope, we applied the same soil model as dry sand slope by adding cohesion. In order to examine the behavior of earth dams during earthquake, shaking table model tests and finite element analysis were performed. The computed acceleration at crest of a model dam showed almost same acceleration as for a model experiment. Simple elasto-perfectly plastic constitutive model give zones of concentrated maximum shear strain similar to the observed shear band and cracks. Less
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