Analysis For Stiffness Match And Effect On Railway Track Structure

With the rapid development of high-speed railway,the train speed continues to improve,how to improve the speed,at the same time,to ensure the safety and smooth operation now become an important research goal.Track Stiffness not only affects the speed of the train,which is a key factor in orbit stress distribution,vibration of the structure,it also affects the interaction and operation of the train wheel and rail,and it is a decisive factor in workload for track maintenance.Track structure has also been strengthened because of the rapid development of high-speed railway.Some of the new high-intensity sleeper,foundation and highly elastic rubber pad made that changing the stiffness of the track structure is very easy to implement.So it is particularly important that analysis of their own characteristics and portions of the track structure stiffness effect.How to change the stiffness of track structure and optimization for the design also has long-term significance.This paper has changed track stiffness of ballasted track structure and ballastless track structure in two aspects which are static analysis and dynamic analysis,the research that changing track structural stiffness affect the structural response as follows:(1)In this paper,an element analysis software has been used to build three-point elastic support beam model which simulate ballasted track structure,based on the actual structure of ballasted track,the forces and role of the various parts of the track and the method of the elastic point support beam model in quasi-static way.14 different conditions have been determined by changing the rail's bending stiffness,fastener's stiffness,roadbed's stiffness and subgrade's stiffness of ballasted track.By loading static load and cyclical dynamic loads on the structure of ballasted track structure,stress and displacement generating by the static loads and dynamic stress,displacement and acceleration generating by the dynamic loads has been simulated in 14 different conditions.(2)An element analysis software has been used to build three continuous support beam model which simulate ballastless track structure,based on the actual structure of ballastless track,the forces and role of the various parts of the track.12 different conditions have been determined by changing the fastener's stiffness,cement and emulsified asphalt mortar(CA mortar)'s stiffness and subgrade's stiffness of ballastless track.By loading static load and cyclical dynamic loads on the structure of ballastless track structure,stress and displacement generating by the static loads and dynamic stress,displacement and acceleration generating by the dynamic loads has been simulated in 12 different conditions.(3)When rail's bending stiffness,fastener's stiffness,roadbed's stiffness and subgrade's stiffness increases linearly,the static response and dynamic response of ballasted track will change linearly.But the trend of influence on the whole structure single rails,sleepers,roadbed is different because different parts stiffness has been changed in ballasted track structure.When fastener's stiffness.CA mortar's stiffness and subgrade's stiffness increases linearly,the static response and dynamic response of ballastless track will also change linearly.But the trend of influence on the whole structure,single rails.track panels,concrete base plate is also different because different parts' stiffness has been changed in ballastless track structure.The fastener's stiffness and roadbed's stiffness in ballasted track structure will change in a certain ratio when they are simultaneously changed.The fastener's stiffness and CA mortar's stiffness in ballastless track structure will also change in a certain ratio when they are simultaneously changed,0.5 has been decided to be the optimal stiffness ratio for ballasted track structure and 0.4 has been decided to be the optimal stiffness ratio for ballastless track structure by comparing different maximum dynamic stress of track structure in different stiffness ratio.Reasonable range of the total track stiffness of ballasted track structure is from 62.943kN/mm to 107.56kN/mm and reasonable range of the total track stiffness of ballastless track structure is from 64.565kN/mm to 113.23kN/mm based on the optimal stiffness ratio.