高速铁路大跨度钢桥无砟轨道结构设计探讨

Structural Design of Ballastless Track for Long Span Steel Bridge of High-speed Railway

目前国内大型钢结构桥梁工程多采用有砟轨道,与无砟轨道相比,有砟轨道几何状态不易长期保持,增加了维修工作量和养护维修设备种类。在大跨度钢桥上推广使用无砟轨道,不仅是实现高速铁路高速平稳运营的要求,同时对于降低工程造价,减少后期轨道养护维修工作量都有积极意义。针对大跨度钢桥无砟轨道方案进行分析研究,推荐桥面预先铺设桥面板方案,其整体性好,有利于桥梁桥面的防腐,也可有效地提高无砟轨道的局部刚度。利用有限元方法,计算分析大跨度钢桥无砟轨道在温度、徐变等作用下的力学状态及规律,以及铺装层-剪力钉这种复合结构的力学行为特性。梁端梁缝结构是大跨度钢桥无砟轨道薄弱环节之一,通过建立车-桥动力学耦合模型模拟分析,确保高速列车行车各项指标未超过安全限值;通过建立不同长度道床板模态模型,研究其振动特征,计算结构固有频率,以预防结构共振;结合大跨度钢桥无砟轨道无缝线路设计,建议在温度跨度150 m及以上应采取必要措施,以确保结构稳定性。最后指出目前大跨度钢桥铺设无砟轨道存在的一些问题,建议运营期间应加强数据监测,以期取得更多经验指导工程实施。

At present,ballasted track is widely used in large-scale steel structure bridge engineering in China.Compared with ballastless track,maintaining long-term geometry of ballasted track is not easy,which increases the maintenance workload and the types of maintenance equipment.The application of ballastless track on long-span steel bridge is not only the requirement of fast and stable operation of high-speed railway,but also of positive significance for saving project cost and reducing the workload of track maintenance in the later period.Based on the analysis and research on the ballastless track scheme of long-span steel bridge,this paper proposes a bridge deck pre-laying scheme,which has good integrity,benefits corrosion prevention of bridge deck,and effectively improves the local stiffness of ballastless track.The mechanical state and the law of ballastless track of long-span steel bridge under the action of temperature and creep are calculated and analyzed by means of finite element method,as well as the mechanical behavior characteristics of the composite structure of pavement shear pin.Beam end beam joint structure is one of the weak links of the ballastless track of long-span steel bridge.The establishment of vehicle bridge dynamic coupling model and simulation analysis ensure that all indicators of high-speed train operation do not exceed the safety limit.Modal models of different length track bed slabs are established to study their vibration characteristics and calculate the natural frequency of the structure to prevent structural resonance.The design of ballastless jointless track on large-span steel bridge should take necessary measures at the temperature span of 150 m and above to ensure structural stability.Finally,the paper points out some problems existing in the laying of ballastless track for large span steel bridge,and suggests that data monitoring should be enhanced during the operation period so as to gain more experience for future projects.