高速铁路桥上有砟-无砟轨道过渡段动力学研究

基于京沪高速铁路特大桥上的有砟轨道与CRTS II型板式无砟轨道之间的过渡段实例,建立车辆-轨道耦合动力学有限元计算模型,通过不同结构处理措施对有砟-无砟轨道过渡段动力学特性的影响研究,研究表明:当有砟轨道轨下胶垫刚度为55~75 MN/m,无砟轨道轨下胶垫刚度为20~30 MN/m时,有砟轨道的整体刚度大于无砟轨道;当有砟轨道轨下胶垫刚度为55~75 MN/m,无砟轨道轨下胶垫刚度为40~50 MN/m时,无砟轨道整体刚度与有砟轨道大体相当;过渡段枕、宽枕等不宜在有砟轨道刚度大于无砟轨道时使用;采用道砟胶结后提高了道床的整体性及过渡段轨道结构的稳定性,但增加了轨道刚度,应同时降低轨下胶垫刚度,以减小轮轨力;辅助轨只是增加了轨道结构的稳定性,对轨道刚度影响较小。

DYNAMIC ANALYSIS OF BALLASTED-BALLASTLESS TRACK TRANSITION SECTION ON HIGH SPEED RAILWAY BRIDGE

Based on the project of transition section between ballasted track and CRTS II ballastless track on super large bridge of Beijing-Shanghai high-speed railway, the finite element model of vehicle-track coupling dynamics is established, and the influence of different structural measures on dynamic characteristics of the transition section are studied. The results show that overall stiffness of the ballasted track is greater than ballastless track when the under-rail pads stiffness of ballast track is 55~75MN/m and that of ballastless track is 20~30MN/m. The overall stiffness of ballasted and ballastless track are roughly identical when the rail pad stiffness of ballasted track is 55~75MN/m while that of ballastless track is 40~50MN/m. Transition sleeper and wide sleeper is unsuitable to be used in the transition section when ballast track stiffness is greater than ballastless track. The ballast glue improves the integrity of ballast bed and the stability of track structure in transition section but it also increases the track stiffness. In order to reduce the wheel-rail forces caused by the increased track stiffness, the rail pad stiffness has to be decreased. The auxiliary rails enhance the stability of track structure but it has little impact on the track stiffness.