Abstract：The dynamic finite element method is employed to analyze the failure mechanism of vaulted tunnel concrete lining and the factors influencing failure range under the impact of explosion. The result indicates that the failure mode of concrete lining is made up of flexure，stress-shear，and cracking into layers under the condition of the explosive closing to concrete lining. With the increase of the distance between the explosive and the lining，the failure range increases firstly. Then，it declines and the failure modes is converted gradually from stress-shear to flexure. The increase of reinforcement ratio can enhance the ability of tunnel resisting failure. As the ratio of thickness to height of cross-section increases，the failure range decreases and the failure mode has the tendency of shearing failure.
