Numerical analysis of seismic response of rectangular underground structure in coral sand

The underground structure in coral sand is threatened by earthquake. The special dynamic characteristics of coral sand were realized by finite difference program. Specifically, the stress–strain loops, shear modulus attenuation and hysteresis behaviour of coral sand were simulated using hysteresis damping. On this basis, numerical models were established to study the seismic response of the rectangular underground structure in coral sand, and the fluid–solid coupling and soil-structure interaction were considered. The results illustrate that the increasing relative density of coral sand foundation reduces the excess pore water pressure (EPWP), but amplifies the horizontal dynamic soil pressure of the coral sand-underground structure system. The increase in the permeability coefficient of coral sand reduces the EPWP accumulation, which leads to an increase of the stiffness and a decrease of the acceleration amplification of coral sand sites.