A Comprehensive Approach to Modeling Stress-strain Behavior of Unsaturated Soils for Geohazard Mitigation

摘要0301457，K. K. Muraleetharan，俄克拉荷马大学诺曼分校“一种综合方法来模拟非饱和土壤的应力-应变行为，以减轻地质灾害“该研究项目涉及地质灾害和与非饱和土壤相关的岩土工程结构的经济设计。 膨胀和收缩的非饱和土会导致土木工程基础设施的破坏，例如降雨引起的残积土边坡失稳。 非饱和土是由固体骨架、孔隙气体和孔隙液体组成的三相多孔介质。 吸力（孔隙气体压力减去孔隙液体压力）是影响非饱和土力学行为的主要因素，基于混合物理论的应力度量选取是该模型的关键。 另一个关键方面是在弹塑性框架内描述土-水特征曲线（SWCC），并将其与土骨架变形充分耦合。 SWCC和土壤变形之间的耦合允许该模型来描述的现象，如收缩引起的含水量减少，湿陷性，和土壤变形的影响SWCC。 一旦开发，本构模型将首先验证在一般应力空间中使用一系列的实验室试验压实粉质土（Minco粉土）使用三轴和空心圆柱装置（HCA）进行非饱和土测试。 一旦在单元素水平上验证，本构模型将被纳入完全耦合的2-和3-维计算机代码。 这些计算机程序将用于模拟静态和动态离心模型试验结果，例如压实土填料的润湿和基底振动引起的路堤沉降，目的是为工程师提供分析在各种土壤湿度条件下承受静态和动态荷载的复杂二维和三维岩土工程结构的能力。 这项研究将通过研究生和本科生参与拟议的研究，以及通过课程工作和创新的课程改革项目，如尽快城市项目，目前正在俄克拉荷马州大学的教育整合。

Abstract0301457, K. K. Muraleetharan, University of Oklahoma-Norman"A comprehensive approach to modeling stress-strain behavior of unsaturated soils for geohazard mitigation"This research project addresses geohazards and the economic design of geotechnical engineering structures associated with unsaturated soils. Swelling and shrinking unsaturated soils can result in damage to the civil engineering infrastructure, such as slope failures in residual soils caused by rainfall. Unsaturated soils are three-phase porous media consisting of the solid soil skeleton, pore gas, and pore liquid. The soil suction (pore gas pressure minus pore liquid pressure) plays a major role in the behavior of unsaturated soils.A key aspect of the proposed constitutive model is the choice of stress measures derived based on mixture theory. Another key aspect is the description of the soil-water characteristic curve (SWCC) within the framework of elastoplasticity and full coupling of it with the deformation of the soil skeleton. The coupling between the SWCC and soil deformation allows the model to describe phenomena such as shrinkage induced by reduction in water content, wetting induced collapse, and the influence of soil deformation on SWCC. Once developed, the constitutive model will be first validated in the general stress space using a series of laboratory tests performed on a compacted silty soil (Minco Silt) using triaxial and Hollow Cylinder Apparatuses (HCA) for unsaturated soil testing. Once validated at the single element level, the constitutive model will be incorporated into fully coupled 2- and 3-dimensional computer codes. These computer codes will then be used to simulate static and dynamic centrifuge model test results such as embankment settlement induced by wetting and base shaking of compacted soil embankments.The aim is to provide engineers with a capability to analyze complex 2-D and 3-D geotechnical engineering structures subjected to static and dynamic loading under a variety of soil moisture conditions. The research will be integrated into education through the participation of graduate and undergraduate students in the proposed research, as well as through course work and innovative curriculum reform projects, such as the Sooner City Project, currently underway at the University of Oklahoma.