Seismic response of fault-crossing tunnel under near-fault motion

抄録

The area where tunnels crossing faults may suffer from severe damage during earthquakes. For fault-crossing tunnels, it is inevitable to be subjected to near-fault earthquake motions when the nearby faults rupture. However, current research rarely considers the impact of near-field motions in seismic analyses of fault-crossing tunnels. In this study, shaking table tests were conducted to investigate the seismic response of fault-crossing tunnels. Both near-fault motion and far-fault motion were adopted as input motions for a comparative analysis of fault site response and tunnel response. The findings reveal a discernible difference in the seismic responses of fault-crossing tunnels subjected to near-fault and far-fault motions. Given equivalent input peak ground acceleration (PGA), near-fault motion markedly amplifies both the acceleration amplification factor, the deformational response, and Arias intensity the fault-crossing tunnel. Furthermore, the origins of this amplification effect can be attributed to two elements: the richer low-frequency components inherent in near-fault motions and the higher PGV/PGA ratio.