Dynamic Response of Rectangular Tunnels Embedded at Various Depths in Spatially Variable Soils

This study investigated the seismic response of rectangular tunnels with various embedment depths considering the spatial variability of soil shear modulus. The spectral representation method was adopted to simulate the anisotropic random field of soil. The excess pore water pressure, the liquefied zone, the ground displacement and the uplift displacement of the tunnel were obtained through the random finite difference method to analyze the seismic response. It was observed that the soil excess pore water pressure ratio under the tunnel gradually decreased and the liquefaction degree reduced with depth increase. The peak value of the liquefied zone range increased with the increase in embedment depth. The mean response of stochastic analysis was smaller than the deterministic calculation results when the tunnel embedment depth was less than 10 m. The maximum tunnel floating displacement obtained from random analyses had the probability of 67.3%, exceeding the value calculated by deterministic analyses when H = 12 m.