大跨度斜拉桥上铺设无砟轨道工程实践

Engineering Practice of Laying Ballastless Track on Long Span Cable-stayed Bridge

研究目的:昌赣高铁赣州赣江特大桥主桥为主跨300 m组合梁斜拉桥,桥上铺设CRTSⅢ型板式无砟轨道,是国内首座铺设无砟轨道的高速铁路大跨度斜拉桥。斜拉桥是柔性结构,在桥面荷载及风力、温度等作用下会产生较大变形,影响无砟轨道铺设精度。需要解决桥上CPⅢ控制网测量的精度问题,并在无砟轨道施工过程中采取精准控制措施,确保成桥后的无砟轨道线形满足要求。研究结论:(1)考虑环境因素影响,优化赣江桥上CPⅢ控制网的测设方案,建立各个CPⅢ控制点在桥轴坐标系下三维坐标的实时改正模型,测量精度满足要求;(2)提出了桥上无砟轨道施工线形控制措施:无砟轨道施工前,通过在桥面预加载获取桥梁真实刚度,并考虑实时温度的影响,得到桥梁的准确线形,通过调整斜拉索索力及利用无砟轨道结构的调整范围逐级修正无砟轨道施工线形;(3)无砟轨道铺设完成后,实测线形与理论线形偏差范围在-10~4 mm之间,满足轨道精调要求;(4)本研究成果可为大跨度桥上无砟轨道的铺设提供参考。

Research purposes:Ganzhou Ganjiang super major bridge is a composite beam cable-stayed bridge with main span of 300 m in Nanchang-Ganzhou high speed railway.The CRTSⅢslab ballastless track is laid on the bridge,which is the first large-span cable-stayed bridge laying ballastless track for high-speed railway in China.Cable-stayed bridge is a flexible structure,so large deformation will occur under the action of deck load,wind force,temperature,etc.This will affect the accuracy of laying ballastless track.It is necessary to solve the problem of measurement accuracy of CPⅢcontrol network on the bridge,and to take accurate control measures in the construction process of ballastless track to ensure that the ballastless track alignment after completion of the bridge meets the requirements.Research conclusions:(1)Considering the influence of environmental factors,the surveying scheme of CPⅢcontrol network on Ganjiang bridge is optimized.The real-time correction model for each CPⅢcontrol point with three-dimensional coordinates in the bridge axis coordinate system is established.And the measurement accuracy meets the requirements.(2)The linear control measures of ballastless track construction on bridge are proposed.Before the ballastless track is laid,the true rigidity of the bridge is obtained by preloading the bridge deck.And the influence of real-time temperature is considered,to obtain the accurate alignment of the bridge.By adjusting the cable force of stay cable and considering the adjustment range of ballastless track structure,the construction alignment of ballastless track is modified step by step.(3)After the ballastless track is laid,the deviation between the measured alignment and the theoretical alignment is from-10 mm to 4 mm,which meets the requirements of track fine adjustment.(4)The research results can guide the laying of ballastless track on long-span bridges.