400 km/h高速铁路无砟轨道列车竖向设计荷载动力学研究

Study on Dynamics of Vertical Design Load for Trains on Ballastless Track of 400 km/h High-speed Railway

随着高速铁路设计速度的提高,轮轨相互作用加剧,对无砟轨道结构设计也提出了更高的要求。本文基于车辆-轨道耦合动力学理论,针对400 km/h高速铁路开展了无砟轨道竖向设计荷载研究。以冲击速度与轮心轨迹两种方法描述扁疤,以短波不平顺描述焊缝,分别考察车轮扁疤和钢轨焊缝两种特殊工况,并结合其动力学计算结果,建议了竖向设计荷载动载系数取值。计算结果表明:(1)400 km/h高速铁路无砟轨道竖向设计荷载动载系数可取3.0;(2)在更高速度下,焊缝引起冲击作用力增大,且轮轨系统动态相互作用对焊缝不平顺幅值变化敏感,因此应严格控制钢轨焊缝不平顺幅值。研究成果可为400 km/h高速铁路无砟轨道设计提供理论指导。

With the improvement of the design speed of high-speed railway,the wheel-rail interaction is intensified,which brings higher requirements for the structural design of ballastless track.Based on the vehicle-track coupling dynamics theory,the vertical design load of ballastless track is studied in this paper for the 400 km/h high-speed railway.The flat damages are described with the methods of impact speed and wheel center trajectory,and the welds are described with the method of short-wave irregularity.The two special working conditions,namely wheel flats and rail welds,are investigated respectively,and the value for the dynamic load factor of vertical design load is suggested based on the dynamics calculation results.The calculation results show that:(1)The dynamic load factor of vertical design load for ballastless track of the 400 km/h high-speed railway may be taken as 3.0.(2)At a higher speed,the impact force caused by weld increases,and the dynamic interaction of wheel-rail system is sensitive to the change of weld irregularity amplitude.Therefore,the amplitude of rail weld irregularity shall be strictly controlled.The research results may provide theoretical guidance for the ballastless track design of the 400 km/h high-speed railway.