中文摘要：

针对由于大跨钢桁梁形变导致其上设置的轨道控制点（CPIII）空间位置的变化,进而导致轨道平顺性的测量结果受到影响的问题,该文从轨道维护角度出发,探讨大跨钢桁梁形变对轨道测量及平顺性影响规律。通过模拟实验对大跨钢桁梁形变引起的自由设站坐标、钢轨几何位置测量值以及轨道平顺性指标3方面的影响进行了深入讨论,结果表明：对于直线段大跨钢桁梁部分的轨道平顺性影响较小,对钢桁梁与两端混凝土梁连接处的轨道平顺性影响较大。

英文摘要：

Considering the spatial position of the track control points（CPIII）,the spatial reference for the track surveying,located on the long-span steel trussed bridge,is varying with the beam deformation,and it will cause undesirable influence on the track regularity measurement.Aiming at the problem,the relationship between the track regularity measurement and the beam deformation was discussed in this paper.The variation of free-station,track geometry and regularity measurement caused by the long-span steel trussed beam deformation were analyzed by simulated data sets.Experimental results showed that the station position and the track geometry were remarkably affected;the main influence of the regularity of the track is located on the region where the steel trussed beam connected to its adjacent concrete beam,while the regularity of the track on the straight steel trussed beam has less influence.