桥梁上铺设无砟轨道的线形控制技术

Alignment Control Technology for Laying Ballastless Track on Bridges

桥梁上铺设无砟轨道时,桥梁变形会导致轨道线形变化,影响铺轨质量,须进行线形控制。本文通过调研统计和计算分析,确定须控制轨道线形的桥型及跨度,然后分析了桥面、底座板和轨面线形的设计方法及控制措施,其中对轨面线形的控制提出了三种方法,并逐一分析其适用条件。结果表明:跨度128 m及以下的桥梁无须采取线形控制措施;中等跨度刚性桥上铺设CRTS双块式无砟轨道时应采取线形控制措施,而铺设CRTSⅢ型板式无砟轨道时可通过轨道精调进行调整;对于柔性斜拉桥,均应采取线形控制措施。桥面施工预拱度的计算不宜计入活载及铺轨完成后收缩徐变产生的变形。设置轨面预拱度和调整轨道施工步骤均适用于变形小的桥梁,大跨度桥宜采用等量压重的措施。应在桥面附属二期荷载施工完毕后再铺设桥上无砟轨道,底座板施工后再次复测CPⅢ点,用于精调轨枕/轨道板的标高。

When laying ballastless tracks on bridges,bridge deformation can cause changes in track alignment and affect the quality of track laying,which needs the alignment control.This article determined the bridge type and span that need to control the track alignment through research,statistics,and calculations.Then,it analyzed the design methods and control measures for the bridge deck,base slab,and track alignment.Three methods for controlling the track alignment were proposed,and their applicable conditions were analyzed one by one.The results indicate that bridges with a span of 128 m or less do not require alignment control measures.When laying CRTS double-block ballastless tracks on medium span rigid bridges,alignment control measures should be taken,while when laying CRTSⅢslab ballastless tracks,adjustments can be made through track fine-tuning.For flexible cable-stayed bridges,alignment control measures should be taken.The calculation of pre arch degree for bridge deck construction should not include the deformation caused by shrinkage and creep after live load and track laying completion.Setting the pre camber of the track surface and adjusting the construction steps of the track are both applicable to bridges with small deformations,and measures of equal weight should be adopted for large-span bridges.The ballastless track on the bridge should be laid after the completion of the secondary load construction of the bridge deck attachments,and the CPⅢpoint should be re measured after the construction of the base slab for precise adjustment of the sleeper/track plate elevation.