【摘要】 在车轮反复碾压作用下，钢轨接头区域易出现马鞍形不平顺、低塌等缺陷。为分析重载铁路钢轨焊接不平顺对有砟道床动力特性的影响，首先建立车辆-轨道耦合动力学模型，计算钢轨焊接不平顺影响下的轨枕上动压力；然后采用离散元分析方法，建立有砟轨道结构二维模型，将焊接不平顺影响下的轨枕上动压力作为荷载输入，模拟分析钢轨焊接不平顺对有砟轨道结构道床动力特性的影响。结果表明：钢轨焊接不平顺显著增加了接头两侧轨枕上动压力，且不平顺短波波长越长，影响范围越大，当波长为0.2 m、波深为0.7 mm时，接头两侧轨枕上动压力增加显著，最大值相较于随机不平顺时增加了50.52%；随着焊接不平顺短波波长的减小及波深的增加，道床垂向加速度、摩擦耗能以及累积变形均随之增加；道砟颗粒间最大接触力受焊接不平顺影响较为显著，尤其当短波波深大于0.5 mm时，最大接触力随波深增加而显著增大；当短波波长为0.1 m、波深为0.7 mm时，相较于随机不平顺，道床应力增加55.89%，距道床顶面0.15 m深度处的道砟颗粒加速度增加了449.42%。更多还原

【Abstract】 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%.更多还原