Dynamic response of the input direction of ground motion to the fault section of large cross-section tunnel

In the ASEISMIC analysis of tunnel passing through fault fracture zone, the influence of earthquake input direction should be considered. The tunnel passing through fault fracture zone of Shantou railway is modeled by ABAQUS simulation software, the reflection superposition effect at the boundary is eliminated by using the infinite element transmission boundary. The dynamic response of the lining in the fault zone of the tunnel under different seismic input directions is analyzed and compared. The results show that: 1 The acceleration response of the tunnel structure is amplified by the fault fracture zone, when the seismic acceleration is input along the tunnel transverse, longitudinal and vertical direction respectively, the acceleration response of the lining in the fracture zone is amplified by 1.127,1.157 and 1.391, respectively. The maximum displacement appears at the top of the arch, the maximum displacement occurs at the vertical input, the next is at the transverse input, and the minimum is at the longitudinal input. 3 The maximum stress occurred at the vault, spandrel and arch foot of the section at the fault interface.