Effect of buried depth on seismic response of rectangular underground structures considering the influence of ground loss

Great efforts have been made in investigating the effect of buried depth influencing the seismic response of rectangular underground structures, however, a consensus hasn't been achieved yet. This paper presents numerical studies on seismic behaviors of rectangular underground structures at different buried depths, and aims to illustrate the rule that buried depth effects the seismic response of underground structures. Firstly, to describe the softening and over-consolidated propertied of soils, a 3D elastoplastic constitutive model was developed. Then the stress states of the underground structures and surrounding soils before earthquakes, which were one of the most important issues and generally ignored in the previous studies, were discussed detailedly. Afterwards, three-dimensional numerical models for nonlinear earthquake response simulations of underground structures were built, and the seismic responses of the rectangular structure at various buried depths and under multiple ground motions were simulated. And vertical and horizontal deformations of both the underground structures and surrounding soils were systematically studied. Consequently, a buried depth of the strongest seismic response for underground structures was proposed based on the exploration of the relations between the buried depth and the structural distortions of underground structures as well as the ground subsidence. Finally, pertinence suggestions were proposed for the seismic design of underground structures at different buried depths.