混凝土大坝地震损伤分析

Analysis on seismic damage of concrete dam

基于大坝混凝土的地震反应特点及损伤力学的基本概念,建立了一种考虑残余应变的混凝土非线性损伤模型。模型中假定混凝土的损伤是各向同性的,损伤状态由拉、压损伤变量予以描述;模型考虑拉损混凝土反向受压时刚度恢复及受损混凝土卸载后存留一部分残余变形,单轴时损伤及残余变形的发展由一组经验曲线表示;混凝土损伤准则由Drucker-Prager曲线形式给出;模型中待定参数由混凝土材料试验结果确定。采用简单的算例对该模型进行考核,并将其应用于Kyona坝体的地震损伤分析中。

Based on the seismic response characteristics of dam concrete and the basic concept of damage mechanics,a nonlinear concrete damage model with consideration of the residual strain is proposed herein;in which it is assumed that the damage of concrete is isotropic,while the damage state can be described with the variables of tensile and compressive damages.Furthermore,it is considered in the model that the stiffness of the tension-damaged concrete will recover under reversed compression and a part of residual deformation will remain in the damaged concrete after unloading,and then a group of experience curves is used to represent the uniaxial damage and the residual deformation development.Moreover,the concrete damage criteria are given by the form of Drucker-Prager curve.The parameters to be determined in the model can be given by the material test of concrete.The model is not only evaluated by some simple cases,but also applied to the analysis made on the seismic damage of Kyona Dam.