Three Dimensional Numerical Simulation of Immersed Tunnel Seismic Response Based on Elastic-plastic FEM

摘要

Using the high performance computer SGI Onyx3800, this paper introduced finite element method in simulating the seismic response of this immersed tunnel in Shanghai. First, consisted of the immersed tunnel, soil and river, a large three dimension solid model was constructed by CAD software according to actual size and geologic circumstance. Second, the finite element model was finished in the CAE software, and the number of nodes and element in final finite element model exceeded 1.2 million and 1 million respectively. Considering the complicity and the diversity of different parts in the model, several material models with distinctive constitution relationships were brought in the research. Contact between two parts also was considered in the research. Such contact regions exist between soil and tunnels segment, GINA rubber gasket and tunnels segment, and between vibration isolation rubber cushions and shear key. All these contact style were treated as surface-to-surface style, and penalty function method was used to solve such problems. The ultimate calculation adopted explicit dynamic algorithm and parallel domain decomposition method. The result reveals the weak joints in this immersed tunnel under Tangshan seismic waves. It could also provide data and references for the aseismatic design of immersed tunnel and its flexible joints.