3D Seismic Response Study on Underground Structures Based on Damaged Plasticity Theory

摘要

The reinforced concrete(RC)underground structure were always taken as solid during an earthquake,though some cracks were induced,no complete collapse of a RC underground structure was recorded until 1995. During the 1995 Kobe earthquake,underground subway structures suffered serious damage,including central column shear failure,which was never been observed in the past. In order to study the dynamic performance of underground structure during earthquake, the damage mechanism of Dakai subway station in Kobe earthquake was analyzed by general-purpose finite element program ABAQUS based on the damaged plasticity theory. In this paper,the soil was described by the extended D-P model, which could reflect the mechanical properties of soil properly. The artificial boundary and the dynamic response of concrete were also taken into account during the simulation. Through the three dimensional(3D)finite element analysis,the failure modes of the central column in Daikai station were simulated. The two dimensional(2D)analysis was also carried on,and the 3D numerical results were compared with the 2D results. The outline of results is summarized as follow:Firstly,the 3D numerical results agree well with the in situ observation. The typical failure mode of underground structure under seismic loading could be predicted by the 3D analysis based on the damaged plasticity theory properly. Secondly,it is necessary to carry on the 3D analysis to investigate the seismic response of the underground structure. The localized 3D effects could not be taken into account in the 2D analysis,the 2D method could not describe the material and geometrical nonlinear behavior of the underground structure precisely.