Influence of Water-rich Fault Fracture Zone on Stability of Tunnel Surrounding Rock

To study the influence of the water-rich fault fracture zone on the stability of the surrounding rock of the tunnel, this paper takes Yonglian Tunnel Project of Jilian expressway as the background. Based on the numerical simulation results of deformation and failure of a section passing through a fault fracture zone, the influence of thickness, inclination angle and head pressure of fault fracture zone on the deformation of tunnel surrounding rock is analyzed. The results show that: the rock displacement of tunnel face will begin to grow at a distance of 9 m from the fracture zone as the tunnel advances. When the separation distance is 6 m, the loose rock ring in front of the tunnel face will be connected with the loose zone of fault fracture zone, and a water-conducting fissure channel will appear to cause a water inrush disaster. When the tunnel face is close to the fracture zone, its maximum longitudinal displacement has little relationship with the thickness of the fracture zone, and it has an exponential decay and linear relationship with the inclination and head pressure of the fracture zone respectively. The maximum displacement of the tunnel in the fracture zone is exponentially decayed, parabolic and linear with the thickness, inclination and head pressure of the fracture zone.