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Mechanism of dilatancy localization of clayey soils under shearing

剪切作用下粘性土剪胀局部化机制

基本信息

批准号：
10650483
负责人：
IIZUKA Atsushi
金额：
$ 1.79万
依托单位：
Kobe University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650483/
关键词：
shear deformation dilatancy strain localization pore water migration soil water coupled problem strength F. E. simulation せん断帯水連成場進行性破壊スケール効果飽和粘性土有限変形理論

项目摘要

Localized deformation appearing in geo-materials has attracted many researchers with expecting the rational explanation of phenomena such as progressive failure and size effect of footing on bearing capacity. In the engineering practice, the specification of strength parameters in an important task in the design work of soil structure. the specimen in the laboratory tests is intended and generally assumed to represent a single point in the in-situ soil medium. However, since the uniformity of stress/strain distribution within the specimen is hardly achieved during shearing, the strength parameters thus obtained cannot be essentially regarded as material properties. In this research project, the mathematical formulation of initial-boundary value problem for soil mass was presented and the finite element code was developed considering pore water migration in the soil media. After examining the numerical stability of the finite element scheme, the triaxial compression shear test of a clay specimen is simulated under the plane strain condition. It is revealed that the shear band observed as the strain localization in clay specimen always develops with dilation, which can be called the localization of dilatancy. Moreover is examined the applicability of such non-linear soil/water coupled formulation in the engineering practice in this study. Particularly, the geosynthetic-reinforced soil structures were considered and their reinforcement mechanism was examined.

岩土材料中出现的局部化变形引起了许多研究人员的关注，人们期望对渐进破坏、地基尺寸效应等现象作出合理的解释。在工程实践中，强度参数的确定是土体结构设计工作中的一项重要任务。实验室测试中的样本旨在并通常假定代表现场土壤介质中的一个点。然而，由于在剪切过程中很难实现试件内部应力/应变分布的均匀，因此所获得的强度参数本质上不能被视为材料特性。在本研究项目中，给出了土体初边值问题的数学表达式，并编制了考虑孔隙水在土壤介质中迁移的有限元程序。在检验了有限元格式的数值稳定性后，模拟了粘土试件在平面应变条件下的三轴压剪试验。结果表明，作为应变局部化的剪切带总是伴随着膨胀而发展的，这可称为膨胀局部化。此外，还对这种非线性土/水耦合公式在工程实践中的适用性进行了检验。特别是，考虑了土工合成材料加筋土体结构，并对其加固机理进行了探讨。