Under the repeated rolling loads from train wheels,the rail weld zone is prone to defects such as saddle-shaped irregularities and squats.To analyze the influence of rail weld irregularity on the dynamic characteristics of ballast bed of heavy-haul railways,this paper first established a vehicle-track coupled dynamics model to calculate the dynamic force applied on the sleepers under the influence of rail weld irregularity.Then,a two-dimensional discrete element analysis model of ballasted track is developed,where the dynamic force on the sleepers is used as input to investigate the influence of rail weld irregularity on the dynamic behavior of ballasted beds.The results show that the rail weld irregularity increases the dynamic force applied on the sleepers on both sides of the joint,with a larger impact range observed for longer wavelengths.When the wavelength is 0.2 m and the wave amplitude is 0.7 mm,the dynamic pressure on the sleepers on both sides of the joint increases notably,with the maximum value increasing by 50.52％compared to that of random irregularity.As the wavelength decreases,the wave amplitude increases,resulting in greater vertical accelerations,higher frictional energy dissipation and bigger cumulative displacement of the ballasted bed.The maximum contact force between ballast particles is significantly affected by rail weld irregularity,particularly when the amplitude exceeds 0.5 mm,with the maximum contact force increasing markedly with the increase in the wave amplitude.When the wavelength is 0.1 m and the wave amplitude is 0.7 mm,compared to random roughness,the stress in the ballast bed increases by 55.89％,and the acceleration of ballast particles at a depth of 0.15 m from the top surface of the ballast bed increases by 449.42％.
关键词
重载铁路/有砟道床/焊接不平顺/动力特性/车辆-轨道耦合动力学/离散元
Key words
Heavy haul railway/Ballast bed/Rail weld irregularity/Dynamic characteristic/Vehicle-track coupled dynamics/Discrete element analysis
维普
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