渗流效应对基于广义非线性屈服准则洞室弹塑性解的影响

Influence of seepage effect on solutions for elastic and plastic around an opening based on generalized nonlinear yield criterion

考虑渗流效应,基于广义Hoek-Brown非线性屈服准则,推导出圆形洞室围岩塑性区半径、洞壁径向位移和洞室周边径向应力的数值解。绘制在考虑渗流的情况下和基于广义Hoek-Brown屈服准则的不同围岩条件下,圆形洞室内外水头差h与R/e(R为塑性区半径,e为洞室半径)的关系曲线、围岩特性曲线和径向应力的分布曲线。研究结果表明:在水头差相同时,位于较差围岩中洞室的塑性区比位于较好围岩中洞室的塑性区发展快;在支护力相同时,支护结构对处于较差围岩中的圆形洞室洞壁位移约束效果较差;在围岩质量较差时,渗流效应对圆形洞室径向应力的影响比围岩质量较好时的影响大。

Based on generalized Hoek-Brown yield criterion, and taking into the effect of seepage account, the numerical solution for radius of plastic zone, radial displacement of tunnel wall and stresses around circular opening were derived. The relation curve between hydraulic head pressure difference h and radius of plastic zone R/e around circular opening for different types of rock masses, ground reaction curve, and distribution curve of radial stress based on generalized Hoek-Brown yield criterion were obtained with seepage being considered. The results show that with the same hydraulic head pressure difference, the plastic zone develops faster in the poor quality rock masses than that in good quality rock masses. For poor quality rock masses, the confinement effect on supporting structure for radial displacement of tunnel wall around circular opening is worse when the supporting force is the same. The influence of seepage effect on radial stress around circular opening is more significant in poor quality rock mass than in good quality rock mass.