Based on the ABAQUS software

the seismic responses of the Dakai metro station under the Kobe earthquake were simulated.The unified hardening model which can reasonably reflect the shear dilatation and strain softening characteristics was utilized to simulate the mechanical behavior of the soil

and plasticity damaged model was employed to describe the mechanical properties of concrete.The three-dimensional numerical model of the Dakai metro station was built.The seismic responses of the Dakai metro station and the surrounding soil were studied under the action of horizontal seismic input

and the combination action of horizontal and vertical seismic input

respectively.Moreover

the seismic damage mechanisms of shallow underground structures were explored.The results indicate that the shear failure occurs first on the overlying soil of shallow underground structures

and then the resisting shear capacity of the soil is lost.Besides

when the overlying soil layer lost its resisting shear capacity

the station structure was loaded with the inertia force of soil under the vertical seismic action.The result is that the middle column was damaged by the compress-shear force which was caused by the inertia force and the shear force from the nearby soil of the sidewall.And then the structure roof was broken

which led to the collapse of the station.