Abstract Tamping can effectively improve the service performance of a ballasted track. To determine the effect of tamping on the mechanical qualities of a ballast bed, a tamp-sleeper-ballasts coupling model was established based on the coupling of the discrete element method (DEM) and multibody dynamics (MBD). This model not only solved the problem that the interaction between ballasts and sleeper could not be revealed accurately by DEM, but also realized the complicated motion simulation of tamp. The model was subsequently verified by field tests. Finally, we applied the model to analyze the macro-mesoscopic motion of ballasts, as well as the effects of tamping parameters on the mechanical qualities of ballast bed. The results show that tamping destroys the uniformity of ballast bed, and the top layer under sleeper and the crib are the most severely affected spaces, whose compactness increased by 7.56% and decreased by 34.77%, respectively. In terms of the analytical results for compactness, lateral resistance, and support rigidity, the recommended lifting height, tamping frequency, and tamping depth are 20 mm, 35 Hz, and 20 mm, respectively. This study can provide critical insights for the improvement of tamping operation.

中文翻译：

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基于DEM-MBD耦合法的夯实作业对道砟床力学性能的影响

摘要 夯实可以有效提高有砟轨道的使用性能。为确定夯实对道砟床机械质量的影响，基于离散元法（DEM）和多体动力学（MBD）耦合建立夯实-卧铺-镇流器耦合模型。该模型不仅解决了DEM无法准确揭示镇流器与枕木相互作用的问题，而且实现了夯实复杂的运动模拟。该模型随后通过现场测试进行了验证。最后，我们应用该模型分析了道碴的宏观细观运动，以及夯实参数对道碴床力学质量的影响。结果表明，捣打破坏了道碴床的均匀性，卧铺和婴儿床下的顶层是受影响最严重的空间，其密实度分别增加了7.56%和34.77%。从密实度、侧向阻力和支撑刚度的分析结果来看，推荐的提升高度、夯实频率和夯实深度分别为20 mm、35 Hz和20 mm。这项研究可以为改进夯实操作提供重要的见解。