Nonlinear Seismic Response Analysis of the Surrounding Rock-Tunnel System in the Mountain Areas Under SV Wave

Abstract

The seismic responses and failure mechanisms of the tunnels embedded in the rock are quite different from those of the aboveground structures due to the dynamic interactions between tunnel and surrounding rock. In the previous studies, the tunnel models were under some extent of simplification without considering much of critical issues such as the three-dimensional (3D) characteristics, nonlinear mechanical properties or initial in-situ stress in the model, which are bound to bring the unpredictable errors in the evaluation of seismic response of tunnel-rock system. In this paper, some 3D nonlinear finite element models are established to evaluate the seismic response of surrounding rock-tunnel system in the mountain areas, considering the initial stress state of surrounding rock-tunnel system induced by gravity and excavation, General Mohr Coulomb nonlinear constitutive. Based on the proposed model, the optimal value of the longitudinal length of the model is firstly discussed to determine the value range of the model size. After that, a series of numerical parametric analyses are carried out to investigate the deformation of the surrounding rock. One important finding is that there exists a most unfavorable stress condition which makes the tunnel induce maximum seismic responses. Finally, the typical control variable method is employed to compare the results of the models established in this paper with those of the model considering or not some of significance factors, the comparison results further prove the necessity of establishing the 3D nonlinear model.