Abstract: The tunnels often cross joints and faults,which have great influence on tunnel stability during their use. In this paper,these joints and faults were approximated as the cracks through the tunnel. In order to study the influence of the cracks crossing the tunnel on tunnel stability under biaxial pressure,some model tests and numerical simulation were implemented. In the experiment study,Longchang sandstone was used to build tunnel models which were a square plate containing a small “ tunnel” and an inclined fault, and in the simulation, Abaqus software was used. Using Abaqus software,the stresses at the points around the tunnel and the stress intensity factor of crack tips were calculated which agreed well with the experimental results. The results show that:① Different angle cracks would have different influence on the stability and strength of tunnel,and produced different stress concentration at the crack tips. When θ is around 40 degrees,the influence of crack on the overall stability and strength of tunnel is maximum,the stress con- centration at crack tips is most obvious,KII value is maximum,its shear failure is more serious,and the peak of failure stress is only 41. 77% of that of tunnels without cracks. ② When θ is around 0 degrees,KII value is close to zero,un- der vertical pressure the cracks close,the stress concentration of crack tips are not obvious,the cracks are more stead- y,the failure stress of tunnel is maximum which is 91. 23% of that of tunnels without cracks,and this position is the strongest for the tunnel stability. ③ Under the influence of vertical stress and confining pressure,the tunnel failure is mainly the pressure-shear failure of the spandrels,side walls,crack tips,and skewbacks,and the tensile failure of arch bottom,vault.