Study On Deformation Characteristic Of Ballasted Track Under Earthquake

Earthquake, which is one of the most serious natural disasters, has caused a serious damages to the railway. Especially the wide adopted ballasted tracks usually have great deformation after earthquakes because of the foundations such as subgrades and bridges are damaged. Sometimes the foundations are not damaged but the track itself goes to destabilize and appears with bending deformation. It will bring severe threat to the safety and steady runing of trains and it will greatly influence the safe operation of railways. So in this paper track deformation under earthquake without foundation damage is researched. The main research works are as follows:A supported grillage girder model is established to solve the seismic response characteristics of ballasted track. And the ballast lateral resistance is simplified as a nonlinear spring which can be used to accumulate the track displacement under earthquake. The finite element method is adopted to discrete the model. Computational analysis method of track accumulated deformation under seismic action is established too.The time-history curves of seismic waves and the related track parameters are determined. The length of the ballast track model is determined by calculation. And a simplified mass-spring model is established to analyze the seismic response characteristics of ballast track.Through calculation and analysis it is found that the seismic waves which perpendicular to track line is most dangerous. On the basis of this, several influence factors such as construction site, seismic intensity, ballast lateral resistance, fastening lateral stiffness, curve radius and sleeper types are considered to research the ballasted track deformation characteristics and laws under seismic wave and relevant conclusions are obtained.Following the season changing and temperature variation, temperature forces are usually existed in the continuous welded rails. So ballasted track deformation characteristics and laws under temperature rise under seismic wave are researched and relevant conclusions are obtained.According to the above analysis conclusion earthquake resistant measure of track is proposed. It will provide theoretical basis for rapid evaluation on track after earthquake.