Alignment Control Technology for Laying Ballastless Track on Bridges
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 CRTS Ⅲ slab 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 CP Ⅲ point should be re measured after the construction of the base slab for precise adjustment of the sleeper/track plate elevation.
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