Abstract: In order to obtain influence of beam-end lateral expansion of steel truss girderon geometrical shape of track，finite element method was employed to establish the calculation model． The model was to analyze variation of geometrical shape of ballast track and its influence factors when relative subgrade of beam-end of steel truss girder had horizontal expansion under the action of the diurnal temperature range． Results indicated that lateral relative expansion between the steel truss girder and subgrade made larger lateral displacement of ballast track while it exerted little influence on track gauge; ballast and fastening lateral resistance had little effect on lateral displacement of track，and on the change rate of track alignment after its increase to normal value when beam-end of steel truss girder had horizontal expansion; the distance from lateral fixed support of steel truss girder to central line of the route was mainly responsible for variation of geometrical shape of track． If the distance could be controlled within 6． 7m，the maximal lateral displacement track would be less than 2mm and change rate of track alignment less than 1‰．

Key words: steel truss girder, beam-end lateral expansion, track, lateral displacement

摘要： 为研究钢桁梁梁端横向伸缩对有砟轨道几何形位的影响规律，运用有限单元法，建立线－桥横向分析的计算 模型，对在日温差作用下钢桁梁梁端相对路基伸缩时有砟轨道几何形位的变化及其影响因素进行分析。结果表 明，钢桁梁相对路基发生横向伸缩后会使有砟轨道线路产生较大的横向位移和方向变化率，但对轨距影响不明显; 梁端伸缩时，道床、扣件横向阻力对轨道横向位移的影响很小，且其增大到正常值之后，轨道方向变化率受其影响 也很小;钢桁梁横向固定支座和线路中线间的距离是影响轨道几何形位变化的主要因素，当其控制在6．7m以内 时，轨道的最大横向位移小于2mm，方向不平顺变化率小于1‰。

关键词: 钢桁梁, 梁端横向伸缩, 轨道, 横向位移