高原铁路大跨桥梁轨道结构选型研究

Type Selection of Track Structure on Long Span Bridge of Railway

某高原铁路地处高海拔、大高差、空气稀薄缺氧的高原高寒地区,部分区段穿越无人区,轨道结构养护维修作业条件差、应急处置困难,在工程技术条件允许的地段应尽量采用无砟轨道结构形式。为指导高原铁路大跨桥梁上轨道结构选型,通过总结国内大跨桥上轨道结构形式的应用现状及不同轨道结构的优缺点,梳理大跨桥上铺设无砟轨道面临的技术问题,并结合工程实践提出了应对方案。研究结果表明:(1)有砟轨道平顺性不宜保持,道床捣固、清筛、换填工作量大,高原铁路大跨桥梁宜优先采用无砟轨道;(2)大跨桥上铺设无砟轨道面临着桥梁竖横向及徐变变形大、轨道长波不平顺不满足验收容许偏差管理值、轨道与桥梁长期相互协调作用及梁端平稳性等问题,需进一步开展针对性研究,完善相关设计规范;(3)大跨度桥梁梁面变形大,CPⅢ控制网点亦会随梁产生较大位移,造成轨道几何状态测不准、评价难,有必要设计科学的控制测量网和适用的测量方案。

The plateau railway is located in the cold region of high-altitude, large elevation difference and thin-air. Some sections pass through unmanned areas. The maintenance and repair of the track structure are in poor conditions and emergency handling is difficult. The ballastless track structure should be adopted as far as possible in areas where the engineering technical conditions permit. In order to guide the selection of track structure on long span bridges on Plateau Railway, this paper summarizes the application status of track structure types on long span bridges in China, and analyzes the advantages and disadvantages of different track structure types. The technical problems in laying ballastless tracks on long-span bridges are sorted out, and solutions are put forward in combination with engineering practices. Research indicates:(1) It is recommended that ballastless tracks should be prioritized on long-span bridges of the Plateau Railway due to the fact that the smoothness of the ballasted track could hardly be maintained, and the works of ballast bed tamping, cleaning and replacement are heavy.(2) The laying of ballastless tracks on long-span bridges is facing a series of problems, such as large vertical, horizontal and creep deformation of the bridge, failure of long wave irregularity of the track to meet the management value of allowable deviation, long-term coordination between track and bridge, and beam stability, which requires further targeted research and improvement of relevant design specifications.(3) The long span bridge beam surface deforms greatly, and the CPⅢ control network points are displaced with beam deformation, resulting in inaccurate measurement of track geometry and difficult evaluation. Thus, it is necessary to design a scientific control measurement network and an applicable measurement plan.