Research On The Impact Of The Earthquake On The Safety Of Running Train On Embankment

As a rapid transit facilities of solving intercity and metropolitan traffic problems, rail transportation, including rail and urban mass transit, is in the national large-scale construction process recently.At the same time,the disaster problem of rail transportation is getting more and more attention,especially for our country with many earthquakes.In our country, many subway lines or along urban rail transit region is in a highly seismic fortification area. Meanwhile earthquakes also cause serious damage to railway facilities and a direct threat to the safe operation of trains. Therefore, the study of the safety of running trains under earthquake is imminent.This paper,summarizing the findings on the basis of their predecessors,use ANSYS software to establish a wheel-rail-roadbed finite element model. The model using the viscoelastic artificial boundary and the ground motion input method of equivalent load, analyzes the dynamic response of soil roadbed and improved soil subgrade. The results show that two kinds of roadbed has an amplification process of seismic wave,and the amplification degree of soil is greater than improved soil subgrade;Both of the displacement and stress in soil roadbed are greater than improved soil subgrade.Moreover, this paper analyze the train running safety under earthquake according to the conventional train safety evaluation.Then it puts forward the relative lateral displacement between wheel and rail evaluation criteria according to the relative vertical displacement between wheel and rail evaluation criteria proposed by Kazuhiko Nishimura.The calculation result is that the relative lateral displacement between wheel and rail evaluation criteria is more conservative and better to ensure the train safety under earthquake.Finally, This paper choosing the Tianjin wave,El centro wave,Taft wave,Qianan wave as the seismic ground motion,using the normalization of seismic waves analyzes dynamic response between wheel and rail,studys the effects of ground motion characteristics on the safty of running trains The results show that the wheel lateral acceleration, the wheel-rail lateral force, the wheel-rail vertical force, the wheel load reduction ratio and the derailment coefficient are enhanced with the increase of ground motion and the rate of the increases are also increase. This indicates that with the increasing intensity of the earthquake, the hazard of the train is increasing exponentially. The same ground motion intensity, different seismic waves spectral characteristics,their wheel-rail power spectral response shows different laws:The wheel-rail lateral force and derailment coefficient is inversely proportional to the predominant period,wheel load reduction rate makes little difference.