Effect of Earthquake on Pressure Arch above the Tunnel

Abstract

Abstract In this paper, the changes in the pressure arch height above the tunnels subject to earthquake were analyzed by using theoretical, numerical, and experimental ways, respectively, and then, a corresponding formula was derived. The phenomenon of stress rotation and pressure arch around the tunnel under earthquake was found by illustrating the stress vector around tunnel. The force transmission method was used to analyze the change in pressure arch height of rectangular, horseshoe-shaped, and circular tunnels before and after earthquake, and then, a new method was presented to determine the pressure arch height above the tunnel under earthquake according to stress changes in surrounding rock. Then, the two methods were jointly used to analyze the pressure arch height above the tunnel. The results show that the tunnel shape has great effect on the shape of pressure arch, and the pressure arch height of deep tunnel varies little with depth. The changes in the shape and height of tunnel pressure arch before and after earthquake obtained from theoretical analysis and numerical simulation were finally verified by shaking table model tests. The research results in this paper may provide practical significance in seismic design of tunnel structures.