Seismic behavior of adjacent underground structures in liquefiable ground

Abstract

The construction of adjacent underground structures is inevitable due to the increased congestion of underground space. Interaction between adjacent underground structures and soil can significantly affect the seismic response of the former. Evaluating the seismic behavior of adjacent underground structures is therefore crucial to ensure safety of these structures. In this study, a dynamic analysis is conducted to examine the seismic response of adjacent underground structures in liquefiable ground. The behavior of saturated sand is modeled using an advanced plasticity constitutive model capable of simulating large post-liquefaction deformation. A finite difference method, validated through dynamic centrifuge model testing, is employed to investigate the influence of different spatial arrangements on the seismic performance of underground structures. The seismic responses of underground structures in various configurations (side-by-side, piggyback, and offset) are assessed by analyzing structural uplift, differences in horizontal displacements, and peak bending moments. The results demonstrate that structural arrangements significantly impact both the deformation and dynamic internal forces of underground structures in saturated sand. The effects of center-to-center spacing and burial depth on seismic response are quantitatively analyzed. The findings emphasize that seismic design must consider the adverse effects of structural arrangement on underground structures in liquefiable soil.