(1. Department of Geology Engineering，Chang¢an University，Xi¢an，Shaanxi 710054，China；2. Key Laboratory of Western China¢s Mineral Resources and Geological Engineering，Ministry of Education，Chang¢an University，Xi¢an，Shaanxi 710054，China；3. Open Research Laboratory of Geotechnical Engineering，The Ministry of Land Resources，Chang¢an University，Xi¢an，Shaanxi 710054，China)
Abstract：According to the structural characteristics and active forms of normal faults in Weihe River Basin，the finite element method is used to simulate the force and deformation of tunnel lining when the road mountain tunnel passes through the normal fault. Calculation is mainly focused at the four major factors which are the movement quantity of fault，the inclination angle of fault，the depth of tunnel and the across angle between tunnel and fault. And the failure modes of lining are concluded. The result shows that the sensitivity of impact of four factors on the lining force and deformation reduced in turn. On the 40 m scope of both sides of the fault fissure is the central location of force and deformation. When the inclination angle of fault is less than 50°，the force of lining is similar to that of cantilever beam with one end fined. Through analyzing and calculating the relative settlement quantity，longitudinal stress and shear stress of the lining，the main failure mode of lining will be divided into three categories. First type is extension-compression，which is actived by large longitudinal stress，then it is extension breakage mainly with compression breakage. Second type is direct-shear，which is controlled by large sheer stress. And the third type is combination of the extension-compression breakage type with direct-shear breakage type.
