Numerical Modeling of the Seismically Induced Uplift Behavior of Twin Tunnels

Abstract

During an earthquake, large movements of soil may cause the instability and uplift of buried structures in liquefied soil. Intensive studies on the uplift behavior of underground structures have mainly focused on a single tunnel. In this paper, numerical modeling is performed to investigate the uplift mechanism of twin tunnels with various configurations under earthquake loading. The excess pore pressure and uplift displacements of twin tunnels with different mutual positions and spacings are analyzed and compared with those of a single tunnel. The effects of the tunnel spacing and the mutual position on the uplift mechanisms of the tunnels are investigated. The results show that the generation of excess pore pressure and the liquefaction of soil surrounding the tunnels are prerequisites for the uplift. The interaction between twin tunnels affects their uplift behavior.