Abstract: Previous study shows that there exit structural planes in rockmass and soilmass and deformation and failure of rockmass and soilmass around engineering projects are controlled by the structural planes. Based on quantitative comparison of integrated preferred index value (R i) of structural planes(faults), we find out the influence degree of structural planes(faults) on tunnel stability.Thus, different measures can be taken for treating the different structural planes(faults). The study result reveals that water hazard, gas outburst and rockmass quality are closely related with the structural planes.