Influence Of Train Vibration On Soil Liquefaction For Roadbed Of Wu Jialong Large Bridge

The study on effects of liquefiable soil on ground vibration and structural seismic response is one of the very important subjects in the earthquake resistant engineering.This thesis takes the study of foundation treatment problems of wujialong large bridge on Xiamen-Shenzhen Railway which across the shanjie highway as the background,and this problem is numerically simulated by fast lagrangian method. According to the actual situation of work sites, rout position of the railway and the highway and the type of pile foundation, four kinds of different foundation models are built, and respectively evaluate the highway foundation treatment effect of these four cases.. The main research content of the article are the following aspects:Combined with the local actual working condition, model size and suitable boundary condition are determined, and the suitable earthquake response spectrum and the train vibration spectrum are input.Using the results of Finite Element Numerical Simulation with FLAC3D, stress contour figures, strain contour figures,pore pressure contour figures, and PPR figures are acquired to analyze the difference between static calculation and dynamic calculation,then according to the liquefaction discriminant basis proposed in this paper, to comprehensively evaluate the safety of highway roadbed.The numerical analysis shows that:(1) In the case of Foundation is not reinforced and the railway bridge is not built, the highway roadbed is unstable under the interaction of earthquake and the most adverse vehicle load,and the phenomenon of sand liquefaction will occur.(2) In the case of Sand Piles Compound Foundation and the railway bridge is not built, the highway roadbed which was reinforced by compaction sand pile is stable under the interaction of earthquake and the most adverse vehicle load,and the phenomenon of sand liquefaction does not occur.(3) In the case of Sand Piles Compound Foundation and the railway bridge is built, the highway roadbed which was reinforced by compaction sand pile is unstable under the interaction of earthquake,the most adverse vehicle load and vibration under wujialong train load,and partially liquefied sand will lost its bearing capacity.(4) In the case of Sand Piles together with CFG piles Compound Foundation and the railway bridge is built, the highway roadbed which was reinforced by compaction sand pile is stable under the interaction of earthquake,the most adverse vehicle load and vibration under wujialong train load, and The phenomenon of sand liquefaction does not occur.