考虑水-应力耦合作用的地下洞室的锚杆支护效果

从建立应力平衡方程、水连续性方程入手,使用Galerkin方法,将各控制方程分别在空间域和时间域进行离散,开发出了一个用于分析饱和岩土介质中水–应力耦合弹性问题的二维有限元程序。通过处于地下水位以下的洞室施工时锚杆支护效果问题的模拟计算表明:在有地下水赋存的条件下,锚杆的作用仍主要是约束围岩位移,但比无水时有所减弱,其对岩体中渗流的抑制效果不大,而渗透系数的取值方式将明显地影响孔隙水压力的分布。

EFFECTS OF SUPPORTING FOR UNDERGROUND OPENING CONSIDERING COUPLED HYDRO-MECHANICAL ACTION

Firstly the momentum equilibrium equation,the continuity equation for water are established. Secondly by using the Galerkin method all the governing equations are discredited in the space domain and in the time domain respectively,thirdly a two dimensional FEM code for coupled hydro-mechanical elastic analysis of saturated porous medium is developed tentatively. Then the computations of the effects of rock bolting for an underground opening located under water table,in which the rock mass is assumed to be saturate,are given. For the cases without water and with water (the seepage coefficient K are constants and the functions of the normal stresses respectively)t,he elastic analyses are carried out by using the developed FEM code. After investigating the distribution states of the displacements and the pore pressures in the rock massi,t is known:under the condition of groundwater existing,(1) the main action of rock bolting is also limiting the displacements of surrounding rock mass but the action becomes weaker compared with the case without groundwater,(2) rock bolting does not have obvious restraining effect for percolation,(3) the determining patterns of permeability values will greatly influence the distributions of pore pressures in rock mass.