Research On Transition Section Between The Ballasted Track And Ballastless Track On Subgrade Of High-speed Railway

The development of high-speed railway should be based on security, reliability and comfort property.Moreover,high-level track regularity and the stability of sub-rail foundation should be guaranteed.The construction of high-speed railway will inevitably encounter transitional section of different sub-rail foundations,which is the weak part in high-speed railway.The difference of the strength,stiffness and settlement of the track in transition section will lead to kink deformation and track irregularities.In order to guarantee the smoothness of high-speed railway line,measures should be taken in transition section to avoide sudden change of stiffness.Based on the former research and the construction of Beijing-Shanghai High-speed Railway,the author establishes a three-dimensional model with commercial software ABAQUS,trying to simulate the dynamic response of transition section between the ballasted track and ballastless track on the railway subgrade.In this paper,the established model is presented in detail,including solid model of ballasted track,solid model of ballastless track,three-dimensional model of transition section between ballasted track and ballastless track,model of track irregularities and model of wheel-rail contact.Combined with related dynamic test data of Suining-Chongqing Railway Line,the reliability of this modeling is approved.Other questions which need special attention, including integral step,grid density,calculation time and boundary conditions are also indicated in this paper.Based on the former model,the dynamic response of transition section between the ballasted track and ballastless track on the railway subgrade of high-speed railway is analyzed with the parameters of track stiffness,rail deflection angle,vehicle speed and driving direction.In this model,ballastless track is common slab track;the sleeper of ballasted track is Typeâ…¢concrete sleeper and the vehicle is motor train unit(300km/h) with distributeed power of self development.The applicability and rationality of different options for transitional section between ballasted track and ballastless track on the railway subgrade of high-speed railway are compared and four plans are recommended.Based on vehicle-track-subgrade coupling dynamic theory,the rationality is studied.Besides, preliminary studies are made on the rational length of transition section between the ballasted track and ballastless track on the railway subgrade of high-speed railway.The research work in this paper can provide theoretical referrence for the design of transition section in high-speed railway of our country.