Response Analysis of Curved Tunnel under Near-Field Long-Period Ground Motion Considering Seismic Wave Propagation Effect

In this paper, long-period ground motion is used as the dynamic input to study the performance evolution of curved tunnel lining structure under seismic wave propagation excitation. This paper presents numerical studies on seismic waves, considering propagation effect, and aims to illustrate the response principle and structural failure mechanism of tunnel structures under long-period ground motion. Firstly, based on the dynamic analysis method, the dynamic balance equation of a tunnel under the seismic wave effect was analyzed. Secondly, this equation was applied to the 3D finite element software, the corresponding numerical model and boundary conditions were established, and the parameterized numerical analysis of the tunnel was carried out. Finally, according to the numerical simulation results, the seismic response principle and structural failure mechanism of a tunnel structure under long-period ground motion were discussed. The research results show that the depth and segment thickness of the tunnel significantly affect the seismic performance of the tunnel. The seismic response mechanism of a curved tunnel is complex, which shows that the relative displacements on the left and right symmetrical positions are different. The displacement inside the curve is less than the displacement outside the curve. Compared with other types of ground motion, the near-site motion considering the seismic wave propagation effect can lead to large deformation of the tunnel, which damages the lining structure greatly, and the enhancement effect is prominent for the long shield tunnel.