DamageAnalysis on Subway Tunnel Structure under Effect of Reverse Fault DislocationAN Shao1，TAO Lianjin1，BIAN Jin2，HAN Xuechuan1，WU Xiaowa1 (1. Beijing Key Laboratory of Earthquake Engineering and Structural Retrofit，Beijing University of Technology，Beijing 100124，China;2. Guang Dong Ocean University，Zhanjiang 524008，China)Abstract:Taking the subway tunnel in Urumqi crossing Xishan reverse active fault as an example，a three- dimensional elastic-plastic finite element model of soil-tunnel structure was established to simulate and analyze plastic strain development process of secondary lining，transverse and longitudinal distribution of tensile damage factor，compressive damage factor and shear strain，calculate the crack width of concrete under the action of reverse fault dislocation. Then the damage law of the tunnel structure with different dislocation displacements,different vertical distances from tunnel bottom to the interface of surrounding rocks and different widths of fault zone was studied. Finally，the disaster reduction effect of the flexible joint was studied. Results show that the damage of secondary lining first appeared in the vault，then the bottom，and finally accumulated at the waist. The shear，tensile and compressive damage all appear at the tunnel waist of the rupture surface. When the tunnel structure is away from rupture surface，the tensile damage appears at the tunnel vault of hanging wall and invert of fault zone，the compressive damage appears at the tunnel invert of hanging wall and vault of fault zone. The severe and slightly tensile-crack damaged length are 10 m and 30 m respectively based on the crack width of concrete. The larger the fault displacement is，the more serious the structural damage is. The larger the vertical distances from tunnel bottom to the interface of surrounding rocks，the thicker the soil is，resulting in that more energy is dissipated and the structural damage is lighter. The damage to tunnel increases with the increase of width of fault zone，but when the width increases to 26 m，the influence of width of fault zone on tunnel damage becomes stable. Setting flexible joints can significantly reduce structural damage and substantially meet the design requirements for fault displacement.