ANALYSIS OF TUNNEL RESPONSE INDUCED BY ACTIVE REVERSE FAULT MOVEMENT

In great earthquakes, active faulting often leads to the rupture in overlying soil and causes significant damages to constructions including tunnels. We simulated the failure process of soil-tunnel system under the active fault movement with a dip angle of 60ånd explored the tunnel response under fault movement. Results indicate that for footwall tunnels, the tunnellocating near the rupture suffers from great moment and shear force. When the tunnel keeps a certain distance from the fault, the moment and shear force decrease rapidly. In order to ensure its safety, the footwall tunnel needs to keep a safe distance of more than 30 m from the fault. For hanging wall tunnels, they bear tiny moment and shear force, but great displacement will be generated under fault movement. Further studies show that soil property including elastic modulus and dilation angle have significant effects on tunnel response. In stiffer soil, a smaller fault dislocation is required for the rupture to reach the ground surface and the tunnel bears smaller peak loads. Greater soil dilation angle leads to a smaller rupture dip angle and the tunnel suffers from larger peak loads.