高速铁路CRTSⅡ型板式无砟轨道稳定性理论研究

摘要

研究目的:目前,纵连轨道板上拱是我国CRTSⅡ型板式轨道主要伤损类型之一.本文基于微分方程法和能量法相结合,采用单波弯曲变形曲线,建立更加符合纵连轨道板实际状态的直板和考虑竖曲线的曲板稳定性分析模型,推导得出稳定性计算公式,研究轨道板稳定性相关参数的影响规律.研究结论:(1)CRTSⅡ型板式无砟轨道应参照无缝线路稳定性理论进行纵连轨道板稳定性分析,得出轨道板最小临界温升幅度,为确定施工锁定板温提供依据;(2)轨道板与砂浆层界面的离缝或削弱是造成轨道板上拱的最直接原因,CA砂浆黏结强度的降低可导致轨道板臌曲临界力大幅度下降,CA砂浆黏结强度降低50％时,临界板温降低25％;轨道板纵向阻力降低50％时,最小临界板温降低5.7％,临界正矢增加38.1％;轨道板初始弯曲越大,最小临界板温越低,临界波长也变长,临界正矢减小;竖曲线对轨道板稳定性的影响很小,最小临界温度力降低不超过1％;(3)本研究成果阐明了纵连轨道板上拱的力学机理和诸多关键参数的影响规律,可为高速铁路CRTSⅡ型板式无砟轨道稳定性研究提供理论参考.%Research proposes:The upwarp deformation of longitudinal connected track slab is one of the major disease forms of CRTS Ⅱ slab track in China at present.Based on the combination of differential equation method and energy method,adopting the track bending deformation patterns with sing-wave,the stability analysis models of longitudinal connected straight track slab and curved track slab which is considering vertical curve are established,and the formula of stability calculation is deduced,and the influence regularity of the parameters related to the stability of the track slab is studied.Research conclusions:(1) For CRTS Ⅱ slab ballastless track,the theory of stability of CWR (continuous welded rail) should be used to analyze the stability of longitudinal connected tack slab,and obtain the minimum critical temperature rise amplitude of the track slab,providing the basis for the stress free temperature of the slab during construction.(2) The open joints or the weakening between track slab and the interface of mortar is the most immediate cause of the upwarp deformation of longitudinal connected track slab.The reduction of the bond strength of CA mortar will lead to the marked decline of the critical buckling load of the track slab.When the bond strength of the cement and asphalt (CA) mortar is reduced by 50％,the minimum critical slab temperature will be reduced by 25％;When the longitudinal resistance of the track slab is reduced by 50％,the minimum critical slab temperature will be reduced by 5.7％ and the critical versine will increase by 38.1％.The larger the initial bending of the track slab,the lower the minimum critical slab temperature,also the critical wavelength is longer and the critical versine is reduced.The effect of the vertical curve on the stability of the track slab is very small,and the reduction of minimum critical temperature force is not more than 1％.(3)The research results clarify the mechanical mechanism of the upwarp deformation of longitudinal connectedtrack slab and the influence rules of the key parameters,which can provide theoretical reference for the stability study of CRTS Ⅱ slab ballastless track on high-speed railway.