Effect of nearby ground structures on the seismic response of underground structures in saturated sand

Abstract With the development of urbanization, underground structures unavoidably come within the vicinity of ground surface structures, and interaction between ground structure, soil, and underground structure interaction can significantly affect the seismic response of underground structures. Three-dimensional high-fidelity numerical dynamic analysis is conducted to investigate underground structures' seismic response in saturated sand with and without a ground structure. In the numerical analysis, saturated sand is simulated using a plasticity constitutive model for large post-liquefaction deformation of sand. The numerical analysis method is first validated based on a centrifuge shaking table test for a ground structure-underground structure system in liquefiable sand, and then applied to reveal the influence of ground structures on nearby underground structure seismic behavior. Results show that nearby ground structures significantly affect the underground structure's seismic response in saturated sand. A ground structure directly above an underground structure can amplify the underground structure's dynamic internal forces and restrict its uplift, whereas a ground structure to the side can amplify the underground structure's deformation and cause rotation. Factors including relative structure positions, ground structure characteristics, and ground motion properties influence the ground structure's effects on the underground structure's seismic response.