Dynamic Stress Concentration Factors and Damage Mode of Horseshoe Tunnels Crossing Fault Fracture Zone

A series of uniaxial compression tests are carried out firstly to confirm the reasonable surrounding rock parameters. Then building up the finite element analysis models of the horseshoe tunnel subjected to the seismic loads. The tunnel buried in different geological conditions, like the different plane angles between tunnel and fault fracture zone (e.g. 0°, 30°, 60° and 90°), different width of the fault zone (e.g. 1 m, 0.5D, 1.0D, 1.5D, 2.0D) (D is the tunnel width). The paper mainly discusses the dynamic stress concentration factors and damage mode on the horseshoe tunnel. Based on the experimental and numerical results, analyzing the distribution of dynamic stress concentration and damage mode on the tunnel, it can be concluded that the tunnel crossing fault fracture zone with the plane angle of 60° and the width of 1.0D are more hazardous, whose vertical convergent deformation, equivalent plastic strain (tensile), tensile damage and the slipping displacement of the fault are in the high level, when compared with other geological conditions simulated in the numerical analysis.