Research On Drawer-type Telescopic Track At The End Of Long-span Railway Bridge

In recent years,with the increasing span of high-speed railway bridges,the influence of train,temperature and wind load on the longitudinal expansion and vertical rotation of long-span bridges has gradually increased,which has brought some difficulties to the laying of long-span beam-end tracks.In order to ensure the stability of the track structure and the safe operation of the train,it is particularly important to set up a more reasonable beam end expansion device at the beam end.Combined with the experience and shortcomings of the existing beam end expansion device,this paper designs a drawer-type expansion track of long-span railway bridge end with large rigidity and large displacement of beam end.By establishing the static and dynamic analysis model of the telescopic track structure,the force,deformation and vehicle driving performance under the static and dynamic loads of the train are analyzed,and the static and dynamic characteristics of the structure are analyzed and studied to verify the rationality and reliability of the structure.(1)The design scheme of drawer-type telescopic track at the end of long-span railway bridge is proposed.This paper expounds the main structure of the beam end drawer type telescopic track and the connection mode between the structures,and expounds the working principle of the joint iron and the telescopic principle of the telescopic track structure.The maximum expansion of the telescopic track structure can reach ±600 mm,which can be applied to railway long-span concrete bridges and steel bridges with train design speed of 300 km/h and below.(2)The stress and deformation of drawer-type telescopic track at the end of long-span railway bridge under static load of train are studied.The static analysis model of drawer-type telescopic track at the end of long-span railway bridge is established,and the stress of the main structure of the telescopic track is analyzed.The stress analysis of the whole track structure is carried out,and the stress and deformation of the whole telescopic track are analyzed to verify the overall safety of the track structure.(3)The dynamic characteristics of drawer-type expansion track at the end of long-span railway bridge under different working conditions are analyzed.According to the train-expansion track dynamic analysis model,analyze the vertical dynamic characteristics of rail,movable steel pillow,displacement box and rail bearing beam when the train runs at different speeds through the drawer type expansion track,and analyze the vertical dynamic characteristics of rail,movable steel pillow,displacement box and rail bearing beam when the train runs at the same speed through the expansion track in two limit states.The safety of the track structure is verified.(4)The driving performance of drawer-type telescopic track at the end of long-span railway bridge is studied.Using the established vehicle-telescopic track dynamic analysis model,the safety and ride comfort of the vehicle when the train passes through the telescopic track at different running speeds are studied.The driving safety and stability of the vehicle under the ultimate tension and ultimate compression state of the beam end drawer type telescopic track are compared and analyzed,and the safety and stability of the telescopic track are verified.