Constitutive Modeling of the Dynamic Anisotropic Response of Soils

本研究项目将研究应力应变（本构） 土的行为时，受到地震荷载，重点放在 各向异性响应尽管许多型号已经在 然而，这种模型的验证是困难的。 该项目涉及一个综合的分析，计算， 实验方案，以确定本构行为。的 分析组件侧重于一个层次模型， 调查人员正在开发。项目的试验阶段 将使用能够装载 试样沿着各种加载路径。将使用超声波方法 测量土样的各向异性程度。立方体 将对装置进行修改，以便可以测量各向异性的程度 在装载、卸载和重新装载期间。的替代 也将考虑超声方法，即测量 样品的电性能。 上述测试将首先以静态方式完成，当验证后， 然后将其推广到动态载荷的情况。为此将 与一些土壤，以验证该技术的各种各样的 地质材料。 最后，本构表征将用于 求解非线性土的典型边值问题 行为例如，动态加载的问题 结构-基础系统，或嵌入 将考虑无粘性土壤。然后计算的响应 将结构-土壤系统的性能与 可用的封闭式解决方案和实验室或现场数据。 首席研究员在国际上享有盛誉， 地质材料本构行为的公式化。 他有专业知识和可用的机构设施 成功完成了所提出的研究。

This research project will investigate the stress-strain (constitutive) behavior of soils when subjected to earthquake loading, focusing on the anisotropic response. Although a number of models have already been proposed, verification of such models is difficult. This project involves a combined analytical, computational, and experimental program to determine the constitutive behavior. The analytical component focuses on a hierarchical model that the principal investigator has been developing. The experimental phase of the project will utilize a multiaxial cubical device which is capable of loading the specimen along various loading paths. An ultrasonic method will be used to measure the degree of anisotropy of the soil specimen. The cubical device will be modified so that the degree of anisotropy can be measured during loading, unloading, and reloading. An alternative to the ultrasonic method will also be considered, namely measurement of the electrical properties of the specimen. The above tests will first be done statically, and when verified they will then be extended to the case of dynamic loading. This will be done with a number of soils so as to verify the technique for a wide variety of geological materials. Finally, the constitutive characterization will be utilized to solve typical boundary value problems involving nonlinear soil behavior. For example, the problem of dynamically loaded structure-foundation systems, or of a foundation pile embedded in cohesionless soil will be considered. Then the computed response of the structure-soil system will be compared qualitatively with available closed-form solutions and laboratory or field data. The principal investigator has an international reputation in the formulation of the constitutive behavior of geological materials. He has the expertise and the institutional facilities available to successfully complete the research proposed.