Effect of peak ground parameters on the nonlinear seismic response of long lined tunnels

Abstract

The response mechanism of tunnels under earthquake loads is a critical issue in tunnels located in seismically active regions. This study aims to investigate the seismic response and damage sensitivity of tunnels under earthquake motions with different peak ground acceleration, velocity and displacement (PGA, PGV and PGD). Based on the design acceleration response spectrum (ARS), four groups of total 40 artificial accelerograms are synthesized with specified PGA, PGV and PGD. In addition, for considering the wave travelling effect on the tunnel axial response, an obliquely incident method for P waves is developed by using the equivalent nodal force method. Then, the nonlinear response of tunnels subjected to artificial accelerograms with different incident angles are simulated, respectively. The numerical results indicate that the PGV and PGA have accretion effect on the seismic response of the tunnel. However, the impact of PGD on the tunnel earthquake response is less evident. The PGV has obvious incremental effect on the dynamic response of tunnels subjected to earthquake P waves with large incident angles. Compared with PGV, the PGA intends to increase the response of tunnels significantly under P waves with small incident angles. Thus, it is important to take the PGA and PGV into account during seismic analysis and design for tunnels.