土体热力学模型的改进及三轴试验有限元分析

Improvement of Thermomechanical Model for Soil and Its FEM Analysis of Triaxial Test

摘要:

基于土体本构模拟的热力学方法,分析了Collins土体热力学本构模型,针对其硬化定律的不足,引入统一硬化参量进行改进,将其扩展为能反映砂土和黏土变形特性的统一热力学模型.运用建立三维临界状态模型的方法将改进模型三维化,并针对常规三轴实验试样的轴对称变形特点,编制了改进前、后的土体热力学模型的有限元程序.对上海粉细砂常规三轴实验的有限元模拟分析表明模拟与试验变形一致,初步验证了模型的合理性和有效性.

Abstract:

Based on the thermomechanical approach to establish elasticplastic constitutive model for geomaterials and analysis of thermomechanical model proposed by Collins,its shortage of hardening law is improved by incorporating unified hardening parameters,then the unified model which is suitable for both clay and sand is presented.After the threedimension being generalized,the finite element method (FEM) computer program of thermomechanical model and the improved model which consider the deformation characters of traditional triaxial test are worked out.Then the improved program is used to simulate traditional triaxial compression tests of Shanghai silt sand,the rationality and validity of the improved model can be seen from the comparison of the calculated results.