三峡花岗岩峰后力学特性及应变软化模型研究 张 帆，盛 谦，朱泽奇，张勇慧

 通过对三峡花岗岩进行常规三轴压缩试验，得到不同围压下的应力–应变全过程曲线。基于弹塑性理论，通过试验数据拟合屈服面，分析研究花岗岩强度参数与峰后应变软化参量的关系，得出在花岗岩的应变软化过程中，黏聚力c随应变软化参量的增大而快速减小，而内摩擦角j在应变软化的过程中几乎保持不变的结论。在此基础上建立花岗岩峰后应变软化模型，利用FLAC3D程序对花岗岩三轴压缩试验进行了数值模拟，其结果与试验数据比较吻合。

STUDY ON POST-PEAK MECHANICAL BEHAVIOUR AND STRAIN-SOFTENING MODEL OF THREE GORGES GRANITE

Based on the conventional triaxial compression tests of the Three Gorges granite，the complete stress-strain curves under different confining pressures have been attained. The test results show that the peak and residual strengths increase，and plastic deformation of the Three Gorges granite can be improved with increasing the confining pressure. Based on the stress-strain curves of triaxial experiments，the softening law of physical property parameters is studied，and a post-peak softening numerical model is established by analyzing the relationship between the strength parameters of granite and parameters of post-peak strain softening with elasto-plastic theory and curve-fitting. Conclusion is drawn that cohesion decreases gradually and keeps almost unchangeable with the increasing of strain softening parameter in the strain-softening process of the Three Gorges granite. The post-peak softening model of granite is used in software FLAC3D to simulate the compression tests，and the numerical simulation based on the model approximately matches the triaxial experiments.