蠕变和中间主应力影响下围岩变形分区弹塑性分析

考虑蠕变和中间主应力的影响，基于巷道变形稳定后围岩的峰值应力应为一定围压下岩石的长期强度的观点和统一强度理论，同时考虑围岩峰后阶段的应变软化和扩容特性，求得了围岩变形分区的弹塑性解析解。最后通过实例分析了蠕变和中间主应力对围岩应力、位移和塑性区半径的影响。研究表明：当忽略蠕变的影响时，一定程度上高估了围岩岩性，塑性区半径的理论结果仅为3.05m，与现场实测结果5.5m相差较大，当考虑蠕变的影响时，塑性区半径的理论结果为5.68m，接近于实测结果|验证了围岩的位移及塑性流动区半径随中间主应力增大而减小的性质，在设计支护时可适当考虑增大中间主应力。研究结果可为软岩巷道的支护力学计算及支护方案设计提供参考。

Elastoplastic analysis of surrounding rock deformation zones with creep and intermediate principal stress

Considering the influence of creep and intermediate principal stress, based on the viewpoint and the unified strength theory that the peak stress of surrounding rock should be the long-term strength of rock under a certain confining pressure after roadway deformation stabilization, and considering the strain softening and capacity expansion characteristics of the post-peak stage of surrounding rock, the elastic-plastic analytical solution of surrounding rock deformation partition is obtained.Finally, the influence of creep and intermediate principal stress on the distribution range of stress, displacement and plastic zone in surrounding rock is analyzed by an example.The results show that when the influence of creep is ignored, the theoretical analysis results of the bearing capacity of the surrounding rock are seriously larger, and the theoretical analysis results of the displacement of the surrounding rock and the distribution range of the plastic zone are seriously smaller due to the non-creep deformation.The intermediate principal stress can obviously inhibit the deformation of surrounding rock and the expansion of the plastic zone. The strength criterion without intermediate principal stress is helpful to eliminate the negative effects of ignoring creep characteristics.