Abstract: The fault-resistant design of tunnel crossing active faults is very important to avoiding the serious damage of cross-fault tunnel structure caused by stick-slip dislocation of reverse fault. Hence, a 1 ∶ 50 similar model experiment for Qipanshi Tunnel is established to study the failure mode of mountain-crossing tunnel caused by stick-slip dislocation of reverse fault, and analyze the deformation process and failure characteristics of tunnel and strata. Some conclusions are drawn as follows: (1) The reverse fault dislocation forms a shear zone in the stratum near the fault trace, and the shear zone develops along the arc direction of the upward disk with a slight protrusion of the fault line. (2) The influence of fault dislocation on the deformation failure of the upper tunnel is greater than that of the footwall; the maximum earth pressure and the maximum longitudinal strain are mainly distributed in the upper tunnel; the soil pressure and longitudinal strain increase with the increase of the dislocation displacement. (3) The ultimate failure of the tunnel is shear failure under reverse fault, which is accompanied by tensile failure locally; the shear failure is mainly manifested as tunnel lining falling off and longitudinal cracks on both sides of the deformation joint; the influence of fault dislocation on the tunnel is mainly concentrated in the fault fracture zone and the 2D (where D is the diameter of tunnel) area around it, especially in the upper part of the tunnel, where enough attention should be paid to during the design of crossfault tunnel.

Key words: tunnel, reverse fault stick-slip dislocation, model experiment, shear zone, failure mechanism