Shaking table model test of immersed tunnels with different site conditions and seismic wave input directions

Given the particularity of the environment of the immersed tunnel, once damage occurs by earthquake, it will cause catastrophic consequences. Therefore, it is necessary to evaluate the seismic performance of immersed tunnel. To study the seismic response law of immersed tube tunnels under different site conditions and seismic wave input directions, we tested four groups of immersed tube tunnel shaking table models. In the experiment, we took three kinds of site conditions into account, including homogeneous dry sand site, homogeneous saturated sand site and heterogeneous site. The test result was as follows: When considering the different site conditions under horizontal earthquake excitations, soil liquefaction significantly influences the propagation of seismic waves, whereas the dynamic responses of the tunnel in the heterogeneous site were larger than those of the other two groups. The input directions of seismic waves have a great influence on the dynamic response of soil layer and tunnel. Furthermore, the relative displacement between tunnel sections was analysed.