Testing and Modeling of Saturated Interfaces in Soil- Structure Problems

在结构-土地基、结构-岩石基础等地质力学问题中，界面和节理处的性态对其在静、动力荷载作用下的响应起着至关重要的作用。尽管过去已经对界面响应进行了实验室测试和模拟，主要是在干燥条件下，但界面孔压对土-结构响应的影响这一重要问题以前还没有得到充分的研究。饱和界面的响应受孔压发展的影响很大，其对结构-基础体系的变形、破坏和承载能力的影响对于安全、经济的设计具有重要意义。这项研究将使用一种新开发的剪切测试设备，该设备允许静态和动态加载以及孔压，包括粗糙度、法向应力、密度、简单和直接剪切条件以及大型试件等因素。由于砂与混凝土之间的界面可以提供一般条件，因此将对渥太华砂-混凝土界面进行一系列的准静态和循环试验。这项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、软化和退化，以及液化模拟(如果试验结果表明)。模型将根据测试数据进行校准，并针对独立测试进行验证。优化程序将允许系统地简化和减少参数，从而实现实际的分析和设计。最后，将制定应用该模型的指导方针，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.