Influence of Groundwater Table Depth on the Seismic Response of Underground Structures in Liquefiable Ground

Climate change and human activities have caused significant fluctuations in groundwater tables in cities worldwide, which in turn substantially influence the seismic response of underground structures in liquefiable ground. This study performs numerical analysis on the influence of groundwater depth on the response of underground structures subjected to seismic loading for typical soil profiles. The liquefiable soil is modeled using the CycLiq constitutive model. Numerical results reveal that shallow‐depth groundwater table rise increases maximum drift ratio and bending moment when liquefiable soil passes through the underground structure, but reduces these responses when liquefiable soil exists only above or below the structure. The presence of liquefiable soil beneath the structure leads to significant uplift as the groundwater table rises. The variation of the drift ratio is influenced by the inertia, initial stiffness, and softening of the surrounding soil. The predominant frequency and peak ground acceleration of the input motion and underground structure depth significantly affect the dependency of the drift ratio and the vertical displacement on groundwater table change. These findings highlight the critical importance of considering groundwater table changes in seismic design and risk assessment of underground infrastructure.