Research on reasonable aseismic fortified length for tunnel through fault fracture zone

With the dynamic analysis and shaking table model test, this paper focuses on the dynamic response characteristics of tunnel through fault fracture zone in longitudinal direction under seismic action. When tunnel is located on the interface of surrounding rock and fault fracture zone, the seismic internal forces and stresses of lining will increase rapidly. When the tunnel cross-section moves away from the fault fracture zone along the longitudinal direction, the seismic internal forces and stresses of lining tend to be stable gradually. The research shows when the angle between the fault and the tunnel axis is in the range of 35°-90°, the reasonable aseismic fortified length for tunnel through fault fracture zone is 3.5 times of the tunnel span. The results could provide a reference for seismic fortification of tunnel engineering.