非规则巷道开挖边界对围岩受力及破坏特征的影响分析

Influence of Irregular Excavation Boundary on Stress and Failure Characteristics of Surrounding Rock

以唐口煤矿深部圆形巷道为例,分别以该巷道的实际形状和光滑圆形为几何边界条件,采用有限元软件ANSYS模拟计算巷道开挖后围岩的应力分布和塑性区范围。结果表明:光滑圆形断面下围岩塑性区范围与基于Drucker-Prager准则推出了解析解相接近;非规则断面下两帮围岩局部破坏,塑性区范围为1.33R_0,45°方向塑性区范围为2.08R_0,大于简化断面的模拟计算值和理论解。因此,评价围岩稳定性必须考虑几何的非规则性所导致的应力集中效应,这对于开挖边界附近的塑性区发展过程产生重要影响。

Taking the circular roadway of Tangkou Coal Mine as an example,the actual shape and smooth circle of the roadway is used as the geometric boundary conditions. The stress distribution and the plastic zone are calculated by the finite element software ANSYS.The results show that the plastic zone of surrounding rock under smooth excavation boundary is close to the analytical solution based on Drucker-Prager criterion,which is less than the results under irregular excavation boundary; the plastic zone range of local failure of surrounding rock of two sides is 1. 33R_0,and the scope of 45 ° direction of the plastic zone is 2. 08R_0. Therefore,it is important to consider the stress concentration effect caused by the irregular geometry,which is important for the development of plastic zone near the excavation boundary.