饱和软粘土的不排水动力本构模型

摘要

Based on the isotropic elastoplastic damage and multi-surface models, a new elastoplastic dynamic model for saturated clay under cyclic loading is proposed which can consider not only isotropic hardening and kinematic hardening but also isotropic shear damage and compression damage. The damage process is described respectively by shear damage variable and compression damage variable and further the damage evolution equations are developed, based on the accumulated plastic deviatoric strain. Numerical simulation of the saturated-clay subsoil subjected to input seismic acceleration shows that new model can preferably depict the dynamic response and then accumulated plastic deviatoric deformation.%根据动荷载作用下饱和软粘土的各向同性弹塑性损伤理论与多曲屈服面模型,提出了一个能分别考虑各向同性硬化、运动硬化以及压缩和剪切损伤的动力损伤本构模型.将压缩和剪切损伤变量表示为累积塑性偏应变路径长度的函数并基于该损伤变量来建立损伤演化方程.分别考虑压缩损伤和剪切损伤能够反映不排水循环加载条件下软粘土动泊松比的变化过程.最后,将模型引入饱和软粘土地基在不排水条件下的地震反应分析中,以验证模型的有效性.结果表明,模型能合理地描述饱和软粘土地基的动力响应及震陷变形.