FAILURE MODE ANLYSIS OF MOUNTAIN TUNNEL SHAKE TABLE TEST IN HIGH-INTENSITY EARTHQUAKE AREA

The model test is accomplished to a mountain tunnel structure in high-intensity earthquake area by the large-scale shaking table model, and the failure modes of the tunnel portal and body and model soil are analyzed. The results show that the cracks of the tunnel slope appear firstly at both tunnel hances and the cracks arise a “X”-shape distribution on the surface of the model soil; it is effective that the shock absorption layer can absorb seismic energy and reduce the number of cracks for the tunnel structure and the rock and soil; there is a tensile fracture at the inner edge of the tunnel vault or at the outer edge of both tunnel side-walls, while there is a shear fracture at the junction of the invert and side-wall and a compressive fracture with dislocation arise at the middle of the tunnel invert. There are a lot of cracks terminated after extending to the ring cracks at the body tunnel and a number of deformation joints are proposed near the broken belt.