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，用于分析饱和土结构在地震过程中和地震后的永久变形。 这是一个由加州大学戴维斯分校和乔治华盛顿大学的主要研究人员参与的小组研究项目。 它涉及到一个已经验证的塑性本构模型到现有的有限元代码的改进和实施。 其目的是提高该代码的能力，以准确地预测饱和土壤的行为之前和液化过程中。 本构模型被扩展到代表粒状土壤的行为，在适度高和非常低的有效应力，使其能够模拟土壤液化之前和期间的行为。 这是通过考虑当土壤接近非常低的有效应力时土壤组构的变化来实现的。 该有限元模型可用于研究地震引起的地基大位移，包括饱和土地基的侧向扩展和沉降，提高预测强震后地基侧向扩展的能力将对减轻地震影响做出重要贡献。

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.