时速350 km高速铁路有砟轨道路基基床结构设计研究

Design Practice of Subgrade Bed Structure of Ballasted Track on 350 km/h High Speed Railway

为完善高速铁路时速350 km有砟轨道路基基床结构设计方法,从列车轴载作用模式、路基面动力影响系数、路基动应力及动变形计算方法等方面着手,分析现行设计方法的不合理之处,并针对性的建立基于填料变形状态控制的基床结构设计方法,主要结论为:(1)参考高铁实车测试数据,建立考虑动车组转向架车轴动力叠加效应的高速铁路有砟轨道路基“动车组双轴荷载作用模式”;(2)提出用于路基基床动强度、长期稳定性及动变形验算的动力影响系数φ_(i),前者为极限动力影响系数φ_(1),后者为频遇动力影响系数φ_(2),时速350 km条件下φ_(1)为1.94、φ_(2)为1.44;(3)根据填料累积变形状态演化规律,以基床以下路基处于快速稳定状态为原则确定基床厚度,以基床填料处于中缓慢稳定亚状态为原则确定基床表层及底层厚度。建立了一套适合高速铁路时速350 km有砟轨道的路基基床结构设计方法,并结合具体算例进行说明。

In order to improve the design method for the subgrade bed structure of the ballasted track of 350 km/h on high speed railways,the irrationality of the current design method is analyzed and targeted subgrade bed structure design method based on the control of the deformation of the filler is established in aspects of axle load function mode,dynamic influence coefficient of the subgrade surface,subgrade dynamic stress and dynamic deformation calculation method.The main conclusions are as follows:(1)With reference to the high-speed rail actual vehicle test data,a high speed railway ballasted track subgrade“EMU dual-axle load action model”considering the superimposed effect of the axle dynamics of the EMU bogie is established;(2)The dynamic influence coefficient φ_(i) is proposed for the dynamic strength,long-term stability and dynamic deformation of the subgrade bed.The former is the ultimate dynamic influence coefficient φ_(1),and the latter is the frequent dynamic influence coefficient φ_(2).φ_(1) is 1.94 and φ_(2) is 1.44 under the condition of 350 km/h;(3)According to the evolution law of the accumulated deformation state of the filler,the thickness of the subgrade can be controlled on the principle that the part of subgrade under the subgrade bed is in a fast and stable state,and the thickness of the surface and bottom layers of the subgrade bed is determined based on the principle that the subgrade bed filler is in a medium,slow and stable sub-state.A set of design methods suitable for subgrade bed structure of the ballasted track at the speed of 350 km/h for high speed railways are created and illustrated with specific calculation examples.