Influence of soil liquefaction on the seismic response of a subway station in model tests

In this work, several shaking table tests are conducted to investigate the seismic responses of a large subway station in various liquefied soil conditions. Different liquefaction states are modeled for the soil foundation by inputting different earthquake intensities. According to the test results, when the lateral soil layer surrounding the underground structure is partly liquefied, the cumulative residual deformations of the subway station are much greater than those in either non-liquefied or completely liquefied ground, which is mainly as a result of the large unrecoverable lateral deformation of the partially liquefied ground. Additionally, when the surrounding lateral soil layer is completely liquefied, the subway station structure experiences significant uplift. When only the soil layer near the upper wall is liquefied, large residual dynamic soil pressures on the sidewall are observed at the end of the test. In addition, the strain distribution rules of the underground structure are clearly altered in the presence of different states of soil liquefaction. These new findings can be used as a basis for evaluating the seismic risk of large underground structures in liquefiable ground.