Study on Rock Mass Stability Effect of High Water Pressure Tunnels by Hydraulic Fracturing Failure

The hydraulic fracturing is one of common failure in hydraulic high water pressure tunnels. The process of hydraulic fracturing of high water pressure tunnel with different initial fracture length in tunnel inner wall is simulated using nonlinear FEM. The couple effect of fracture inner water pressure with surrounding rock mass deformation is considered in the model. The fracture propagation process with increasing of tunnel inner water pressure is analyzed, its effect on stress, displacement and plastic zone of tunnel surrounding rock mass is obtained. The results are compared with that obtained without considering existence of fracture water pressure. There are different results from two analysis method. The results show that only couple analysis can obtain relative authentic stress, displacement and plastic zone of tunnel surrounding rock mass, providing base data for correct stability assessment of surrounding rock mass.