Inertia force-displacement method for seismic analysis of shallow buried underground structures

As for the existing practical methods for seismic analysis of underground structures, including seismic coefficient method, free-field racking deformation method, flexible coefficient method, response displacement method, response acceleration method and Pushover analysis method, the inertia force of overburden backfilled soil or overburden soil which has shear failure under the vertical ground motion is not considered. The recent researches show that the vertical inertia force of overburden soil has important influence on the seismic performances (shear strength and ultimate deformation) of support components for shallow buried underground structures. And it is also one of the critical factors in the seismic safety evaluation of shallow buried underground structures, which cannot be ignored. A response displacement method is proposed for seismic analysis of shallow buried underground structures considering the vertical inertia force of overburden soil, called inertia force-displacement method for short. The determination methods for two critical parameters are given, including the foundation spring coefficient and the maximum vertical inertia force of overburden soil layer. The analysis results of engineering projects show that the inertia force-displacement method overcomes the defect of the classical response displacement methods which cannot calculate the axial force of the center column, and the other results have a similar calculation accuracy compared with those of the classical response displacement methods.