Discussion on Dynamic Numerical Simulation for Earthquake of Immersed Tunnel at Seabed

The finite element limit analysis method is applied to study the reinforcement concrete immersed tunnel at seabed under earthquake in this paper. FLAC3D is adopted to establish the equivalent model of reinforcement concrete, and the solution is executed according to elastic-plastic plane problem. Firstly, it is indicated that there are extreme strain values for concrete and reinforcement concrete, and the finite element limit method is adopted to calculate the ultimate shear strain value of equivalent material test pieces of reinforcement concrete of immersed tunnel so as to judge whether the immersed tube failures, thus, a new failure criteria for finite element limit analysis of immersed tunnel is provided. Secondly, the location and shape of failure surface of the immersed tunnel are simulated and its safety factor is obtained, and relation curve between subsidence displacement of top plate and strength reduction factors is combined to analyze the whole failure process of immersed tube. Finally, the influence law for safety factors of immersed tunnel under the function of different seismic wave.