Abstract:To improve the damping performance of fault-crossing tunnels in dangerous mountainous areas with high-intensity earthquakes, based on the Menggushao tunnel engineering of Lixiang Railway, this paper used the finite differential software FLAC3D to study the damping effect of the shock absorption layer of the fault-crossing tunnel under different setting modes. Results showed that if the shock absorption layer is set between the primary support and surrounding rock, the lateral displacement, the vertical displacement, the maximum principal stress, the minimum principal stress, and the maximum shear stress will decrease by 4.17%, 14.32%, 47.89%, 25.93%, and 27.74%, respectively, and the minimum safety factor will increase by 34.62%-59.40%; If the shock absorption layer is set between the primary support and secondary lining, the lateral displacement, the vertical displacement, the maximum principal stress, the minimum principal stress, and the maximum shear stress will decrease by 3.72%, 7.73%, 16.11%, 20.21%, and 20.73%, respectively, and the minimum safety factor will increase by 0.04%-28.38%. The damping effect of the shock absorption layer, set between the primary support and surrounding rock, is better than that set between the primary support and secondary lining. This study is of great significance for the damping design and damping shake technology of fault-crossing tunnels.