Abstract:A high-precision indirect boundary integral equation method (IBIEM) was adopted to simu-late the scattering effect of seismic waves on the mountain-fault fracture zone-tunnel model, consider-ing three influencing factors: incident wave intensity, the distance between the tunnel and fault fracturezone, and the dynamic characteristics of the fracture zone. The impact of these factors on the seismicdynamic response of the mountain surface and tunnel was analyzed. The results showed that the pres-ence of the fault fracture zone complicated the interactions within the mountain-fault fracture zone-tun-nel system. The displacement amplitude of the mountain surface, as well as the displacement andstress amplitude of the tunnel, primarily exhibited magnification effects. Damage was particularly se-vere at the fracture of the mountain surface, with displacement amplitudes sharply increasing to more than 10 units. Stress concentration was more notable at the spandrel and arch foot of the lining, whilestress at the top and bottom of the lining was relatively small. When seismic waves were incident atlow frequencies, the stress and displacement curves of the tunnel's inner and outer walls were relative-ly smooth. As the incidence frequency increased, the coherence effect of the wave became more pro-nounced, causing spatial redistribution in the lined tunnel, with peak values concentrated in multiplesections. The research results can provide a theoretical basis for seismic design of tunnel structuresnear fault fracture zones in mountains.
