Numerical Simulations of Seismic Responses of Concrete Segments for Tunnel Linings in Shenyang City

Abstract

In order to evaluate the influence of seismic action on internal forces on segments, the seismic responses of concrete segments for tunnel linings in Shenyang city are numerically simulated with finite element method. The seismic inputs acting on bottom of FEM model are modified in order to make peak value of accelerations on ground surface equal to 1m/s2 based on code for seismic design of buildings. The investigations show that, by comparing with those of the seismic inputs on bottom of FEM model, the predominant frequency of ground surface movements is significantly modified because the soil has an important filtering effect. By comparing with the peak value of accelerations of seismic inputs on bottom of FEM model, the peak value of accelerations on ground surface is only amplified as 1.57 times because the elastic moduli in different soil layer have little different. The maximum bending moments on segment linings induced by static soil loading are 496kN·m. The maximum bending moments on segment linings induced by seismic loading are 58kN·m. The maximum bending moments on segment linings induced by static soil loading are located in roof, floor and two side walls. However, the maximum bending moments on segment linings induced by seismic loadings are located in left and right spandrels. On those sites, the bending moments induced by static loading approaches zero. By comparing with the maximum bending moment on segment linings induced by static soil pressure, the maximum bending moment superposed by static and dynamic loadings only increases 0.4%.