ELASTO-PLASTIC RESPONSE ANALYSIS OF A COMPLICATEDSHIELD TUNNEL SYSTEM SUBJECTED TO INCIDENT SEISMICWAVES

摘要

According to the analysis model of the equivalent continuity stiffness of the shield lining, this paper buildsup a practical procedure to evaluate the elasto-plastic stress developed in a complicated shield tunnelsystem subjected to incident seismic waves. The shield lining is simulated by the beam supported on soil,having the same stress-deformation relation as that of the original segments-joint structure. The finiteelement method has been used to calculate the internal forces when a seismic wave passing the shieldtunnel. The calculated results show that the transition stress caused by wave propagation could reach asignificant value in comparison with the case of stable harmonic wave. As a numerical example, theprocedure is applied to analyze the stresses of Yanan East Road Tunnels across the Huangpu River inShanghai subjected to several practical seismic waves. The numerical results displayed that the stressesnear the joint of the shield tunnel and the vertical vent shaft are rather lager than that generated in generalregion of the tunnel. The numerical results also show that the transient stress, the stress concentration andthe frequency characteristics of the seismic waves are the important factors to influence the seismic stressdistribution in the shield tunnel.