路基冻胀对CRTSⅢ型板式轨道变形的影响研究

Research on the Influence of Subgrade Frost Heave on CRTS Ⅲ Slab Ballastless Track

研究目的:严寒地区高速铁路路基冻胀变形时常出现,局部冻胀变形不仅影响无砟轨道的平顺性,还可能导致层间离缝发生。为此,本文建立CRTSⅢ型板式无砟轨道-路基系统有限元模型,以分析不同路基冻胀波长和路基冻胀幅值下轨道结构的变形特征。研究结论:(1)路基冻胀作用下轨道结构各层的上拱变形与路基冻胀波形基本一致,轨道结构各层的变形受路基冻胀位置影响较大;(2)轨道结构各层的变形、轨道结构层间离缝以及轨道结构各层的上拱波长均随路基冻胀幅值的增大而增大,且底座板与路基表层的离缝远大于自密实混凝土与底座板间的离缝;(3)随着冻胀波长的增加,轨道结构各层的位移、轨道结构层间离缝随之减小,但轨道结构各层的上拱波长逐渐增大;(4)冻胀波长增大对轨道结构变形和减小层间离缝有利,路基冻胀幅值限值应根据冻胀波长来确定;(5)本研究成果可为路基冻胀变形控制提供参考。

Research purposes:The subgrade frost heaving deformation often appears in severe cold area.Local frost heaving deformation will not only affect riding comfort,but also lead to interlayer seam.In order to analyze the deformation characteristics of track structure under different frost heaving wavelength and amplitude,a system finite element model for CRTSⅢballastless track-subgrade was established.Research conclusions:(1)The upwarp deformation of each track-subgrade structure layer is basically in accordance with frost heaving wavelength,and frost heaving position has a great influence on track structure deformation.(2)The displacement of each track structure layer,interlayer seam and upwarp wavelength increase with the increase of the frost heaving amplitude,and the seam between bed plate and subgrade surface is much larger than that between self-compacting concrete and bed plate.(3)With the increase of the frost heaving wavelength,the displacement of each track structure layer and interlayer seam decrease,and the upwarp wavelength of each layer increases.(4)The increase of frost heaving wavelength is beneficial to reduce track structure deformation and interlayer seam.The subgrade frost heaving amplitude depends on its wavelength.(5)The research conclusion can provide a reference for the deformation control of subgrade frost heaving.