高速铁路无砟轨道车辆荷载传递特性研究

Study on the Load Transfer Characteristics of Ballastless Track in High-speed Railway

为进一步探讨无砟轨道荷载设计参数取值,为我国时速400 km及以上高速铁路建设提供重要理论支撑,通过开展无砟轨道静力分析以及钢轨焊缝、车轮扁疤激励下车辆-轨道动力相互作用,揭示列车静、动力载荷特征及传递规律;同时根据轨道承载特点和无砟轨道设计原理,提出车辆竖向设计荷载取值建议。研究结果表明:(1)高速列车车轮扁疤和钢轨焊缝不平顺将造成显著的轮轨冲击,其轮载动载系数最大可达5.79,远高于现行规范取值;扣件系统对扁疤和焊缝不平顺引起的轮轨力高频成分衰减作用明显,扣件支反力的动载系数最大为2.64;(2)钢轨焊缝不平顺引起的轮轨冲击力随着车速提高以及焊缝不平顺幅值的增大而迅速增大,建议500 km/h及以下高速铁路的钢轨焊缝平直度标准取0.2 mm/m;(3)列车轮载通过扣件支反力作用于轨道板,从传递特性的角度来说,以扣件支反力作为轨道板竖向设计荷载更为合理,其动载系数可取3.0,且能满足400 km/h及以上高速铁路的行车需求。

To further explore the load design parameters of ballastless tracks and provide theoretical support for the construction of high-speed railways operating at 400 km/h and above in China,a study was conducted through static analysis of ballastless tracks and vehicle-track dynamic interaction under the excitation of the rail welds and wheel flats.This study revealed the characteristics and transfer patterns of static and dynamic loads from trains.Based on the load-bearing characteristics of the track and the design principles of ballastless tracks,suggestions for the vertical design load values of vehicles were proposed.The results showed that:(1)Rail weld irregularities and wheel flats could cause significant wheel-rail impacts on high-speed trains,with the maximum wheel dynamic load coefficient reaching 5.79,which far exceeded the values specified in the current standards.The fastener system significantly attenuated the high-frequency component of the wheel-rail forces caused by wheel flats and rail weld irregularities,with the maximum dynamic load coefficient of fastener support reaction force reaching 2.64;(2)The wheel-rail impact force caused by rail weld irregularities rose rapidly with train speed and the amplitude of the irregularities.It was suggested that the rail weld flatness standard for high-speed railways at speeds up to 500 km/h should be 0.2 mm/m;(3)Wheel load was applied to the track slab through the fastener reaction force.Therefore,from the perspective of transfer characteristics,it was more reasonable to use the fastener reaction force as the vertical design load for the track slab,and a dynamic load coefficient of 3.0 could meet the operation requirements of high-speed railways at speeds of 400 km/h and above.