Collaborative Research: Constitutive and Numerical Modeling for Analysis of Permanent Deformations of Soil Structures

本研究计划的目的是开发一个计算效率高的数学模型，用于分析地震期间和地震后饱和土结构的永久变形。这是一个小组研究项目，涉及加州大学戴维斯分校和乔治华盛顿大学的主要研究人员。该模型基于有限变形两相混合理论。它涉及到一个已经验证的塑性本构模型的改进和实现到现有的有限元代码。目标是提高该代码的能力，以准确地预测液化前和液化过程中的饱和土壤的行为。本构模型被扩展到表示颗粒土在中等高和非常低的有效应力下的行为，使模拟土壤在液化之前和液化过程中的行为成为可能。这是通过考虑土壤接近非常低的有效应力时土壤结构的变化来实现的。利用所建立的有限元模型研究了液化引起的大位移的机理，包括饱和土沉积物的横向扩展和沉降。提高预测强震后土壤基础横向扩展的能力，将对减轻地震的影响作出重大贡献。

The objective of this research program is to develop a computationally efficient mathematical model for analyzing the permanent deformation of saturated soil structures during and following an earthquake. This is a group research project involving principal investigators at the University of California-Davis and George Washington University.The model is based on a finite deformation two-phase mixture theory. It involves the improvement and implementation of an already-validated plasticity constitutive model into an existing finite element code. The goal is to enhance the capability of this code to accurately predict the behavior of saturated soils prior to and during liquefaction. The constitutive model is being extended to represent the behavior of granular soils, both at moderately high and at very low effective stresses, making it possible to simulate the behavior of soil prior to and during liquefaction. This is achieved by considering the change of soil fabric as the soil approaches very low effective stresses. The resulting finite-element model is used to study the mechanism of liquefaction-related large ground displacements, including the lateral spreading and settlement of saturated soil deposits.Advancing the ability to predict the lateral spreading of soil foundations following strong ground shaking will be a significant contribution to mitigating the effects of earthquakes.