Influence of relative distance between fault and tunnel on dynamic response of tunnel: An experimental and numerical investigation

The effect of earthquakes on deep tunnels near faults has always been a significant issue in underground engineering research. The presence of fault fracture zones tends to intensify the seismic response of tunnels. On the basis of the Xianglushan tunnel project, the influence of relative distance between fault and tunnel on the dynamic response of tunnel was investigated utilizing laboratory test, shaking table test, and numerical simulation. The results indicated that as the relative distance between the fault and the tunnel increased, the peak acceleration and peak strain of the tunnel first increased and then decreased. The results of numerical simulations and experimental tests demonstrated that changes in relative distance had a significant influence on the dynamic response of the tunnel. Since the Xianglushan tunnel is located near the fault, the superposition of seismic load and the residual tensile and compressive stress led to the appearance of through‐type cracks, which eventually resulted in large deformation or even failure. The left arch springing and left spandrel of the tunnel closer to the fault were prone to failure first. This study provides a reference for the seismic dynamic response and failure mechanism of near‐fault tunnels.