城市轨道交通中小半径大坡道高架桥上无缝线路优化设计

Optimization Design of CWR on Steep Gradient Viaduct with Small Radius in Urban Mass Transit

减小轨道、桥梁受力,防止轨道因爬行而积聚纵向力,是城市轨道交通中小半径大坡道高架桥地段无缝线路设计的技术关键。以南京地铁南北线一期工程中半径R=350 m曲线地段的安德门和东井亭高架桥以及33‰大坡道地段无缝线路为例,研究实现优化设计的关键技术。利用在道岔的岔道与曲线头之间的直线段,增设一组单向钢轨伸缩调节器,避免道岔承受无缝线路的纵向力,同时也减小高架桥的墩台受力。对于小半径线路,调整锁定轨温,用最大温度拉力取代断轨力,用温度力的侧向分力和列车通过桥梁时的离心力叠加检算墩台受力。对于大坡道地段,采用控制爬行量或钢轨应力,确保运营安全。

Reducing the mechanical force of track and bridge, preventing the track from accumulating longitudinal force due to track creeping are the key techniques for the design of continuously welded rail （CWR） on steep gradient viaduct with small radius in urban mass transit. The key techniques for achieving the optimization design are studied by taking the example of Andemen and Dongjingting viaducts on the curve section with R=350 m, and CWR on 33%0 steep gradient section of Nanjing Metro Project, NorthSouth line phase 1. A set of unidirectional rail expansion joint is added on the straight-line section between the turnout start and the curve start in order to avoid the turnout from the longitudinal force of CWR. At the same time, the mechanical force on the pier and the abutment of Andemen viaduct is also reduced. For track with small radius, the mechanical force of the pier and abutment is checked and calculated by adjusting the fastening-down temperature of rail, replacing the rail breaking force with the maximum temperature tension, and superposing the lateral force component of the temperature force with the centrifugal force when train passing through the bridge. For steep gradient section, the operation safety is guaranteed by controlling the rail creepage and rail stress.