Testing and Modeling of Saturated Interfaces in Soil- Structure Problems

在结构-土基础、结构-岩基础等岩土力学问题中，结构-土基础系统的界面和节理特性对其在静、动荷载作用下的响应起着至关重要的作用。虽然过去已经进行了界面响应的实验室测试和建模（主要是在干燥条件下），但界面孔隙水压力对土-结构响应的影响这一重要问题尚未得到充分研究。饱和界面的响应受孔压发展的显著影响，其对结构-基础体系的变形、破坏和承载能力的影响对结构-基础体系的安全和经济设计具有重要意义。本研究将使用新开发的剪切试验装置，该装置允许静态和动态加载以及孔隙水压力，包括粗糙度，正应力，密度，简单剪切和直接剪切条件以及大尺寸试样等因素。由于砂-混凝土界面可以提供一般条件，因此将对干和饱和渥太华砂-混凝土界面进行一系列准静态和循环试验。研究的另一个主要目标是发展统一的扰动状态概念（DSC），该概念允许弹性和塑性变形，硬化，软化和降解，以及液化模型，如果在测试结果中表明。该模型将根据测试数据进行校准，并通过独立测试进行验证。优化程序将允许系统地简化和减少参数，以实现实际的分析和设计。最后，将制定模型应用指南，包括通过非线性有限元程序。

The behavior at interfaces and joints in geomechanical problems such as structure-soil foundation, and structure-rock foundation systems plays a vital role in their response under static and dynamic loads. Although laboratory testing and modeling for the interface response, mostly under dry conditions, have been performed in the past, the important issue of the effect of pore water pressures at interfaces on the soil-structure response has not been fully investigated before. The response of saturated interfaces is influenced significantly by the pore pressure development and its resulting effect on deformations, failure, and load carrying capacities of the structure-foundation systems is important for safe and economical design. This research will use a newly developed shear test device that allows static and dynamic loading and pore water pressures with inclusion of factors such as roughness, normal stress, density, simple and direct shear conditions and large-sized specimens. As interfaces between sand and concrete can provide a general condition, a series of quasistatic and cyclic tests on dry and saturated Ottawa sand-concrete interfaces will be performed. Another main objective of the research is to develop the unified disturbed state concept (DSC) which allows elastic and plastic deformations, hardening, softening and degradation, and modeling of liquefaction if indicated in the test results. The model will be calibrated based on the test data, and validated with respect to independent tests. An optimization procedure will permit systematic simplification and reduction in parameters, toward practical analysis and design. Finally, guidelines for application of the model, including through nonlinear finite element procedures, will be developed.