基于强度参数演化行为的岩石峰后应力-应变关系研究

基于岩石材料峰后强度参数的演化行为，结合强度准则，提出了建立峰后应力-应变关系的一般方法。在此基础上，基于摩尔-库仑强度准则，以最大主应变 作为应变软化参数，假设黏聚力 ，内摩擦角 为主应变 的分段线性函数条件下，给出了岩石材料的峰后应力-应变关系式的求法。在数值算例中，利用提出的方法，给出了大理岩在不同围压下的应力-应变曲线，算例显示，利用这一方法求得的峰后应力-应变关系曲线变化趋势与试验数据基本一致，表明该方法在研究峰后应力-应变关系上具有一定的合理性。

Study of post-peak stress-strain relationship of rock material based on evolution of strength parameters

The post-peak deformational characteristics of rock materials play a leading role in safety of geotechnical engineering. So it is important to study the post-peak stress-strain relationship. Based on the evolution of post-peak strength parameters of rock material, a general method for establishing the stress-strain relationship is presented. Firstly, strength criterion is selected to establish the connection of stress with strength parameters. Then, the relationship between strength parameters and strain softening parameter is determined. Finally, the post-peak stress-strain relationship can be obtained by strength parameters which are as intermediate variables. On this basis, based on Mohr-Coulomb strength criterion, regarding maximum principal strain as strain softening parameter, on the assumption that the cohesion and friction angle are the piecewise linear functions of , the method of solving express of post-peak stress-strain relationship is obtained. In numerical cases, the stress-strain curves under different confining pressures are obtained and they agree well with the test data. It reveals that the method proposed by this paper is reasonable and effective in studying post-peak stress-strain relationship.