土路基—刚性基础板式轨道过渡段动力特性分析

Dynamics Characteristic Analysis of Embankment-rigidity Bed Transit Section

研究目的：目前，我国拟在高速铁路的土路基上铺设无砟轨道，由于高速铁路的轨道要求有更高的平顺性和舒适性，因此本文从车辆-轨道耦合大系统的角度出发，探讨土路基与刚性基础的过渡区段的动力特性，以期为过渡段的设计和施工提供理论支持和参考依据。研究方法：基于车辆-轨道耦合动力学理论，建立了土路基-刚性基础过渡段模型，编制了动力学仿真计算程序，对过渡段的动力特性进行了仿真计算分析。研究结论：在土路基-刚性基础过渡区段，轨道基础刚度差产生动力作用不是很大，但钢轨挠度变化显著；差异沉降对轮轨系统的动力作用十分剧烈，考虑30mm／10m的差异沉降，车体加速度达到1．0m／s。时，接近舒适度管理目标值0．13g；随着速度的提高，动力作用加剧，当运行速度从250km／h提高到350km／h时，最大轮轨垂向作用力从92kN提高到104kN，而最大车体加速度从1．0m／s^2提高到1．4m／s^2，此时已经超过了安全限值；过渡段的设置长度宜以车体加速度为主，最大差异沉降为30mm的过渡区段，过渡段的长度可以设置在25—30m之间。

Research purposes： Currently, slab track will be built on embankment in some HSL in domestic, the track of HSL requires higher regularity and higher steady. This paper bases on vehicle - track large system, researches the dynamics characteristic of embankment - rigidity bed transit section and provides theories support and consult basis for design and construction. Research methods： Based the vehicle -track coupling dynamics, the embankment - rigidity bed transit model is provided, then computer program is worked, and dynamics characteristic of embankment - rigidity bed transit section is simulated. Research conclusions ：At transit section, dynamic interaction is very slight due to track stiffness difference, but the variety of rail deflection is obvious. Asymmetrical settlement of foundation has remarkable influence on track structure and the steady of vehicle, the acceleration of vehicle will attain 1.0 m/s^2 if there exits 30 mm/10 m Asymmetrical settlement, and the influence becomes greater with increasing of speed; the length of transit section should make the acceleration of vehicle as chief index, the length of transit section can establish as 25 - 30 m if there exits 30 mm asymmetrical settlement.