铁路道床振动特性的三维离散元分析

Analysis of Ballast Dynamic Behavior with Three-dimensional Discrete Element Method

研究目的:铁路碎石道床是一种典型的散粒体结构,为突出考虑道砟颗粒的散体特性,运用离散元法建立轨枕-道床空间耦合的颗粒流模型。通过加载高速列车动荷载时域谱,研究铁路道床在高速行车条件下的振动特性和道砟颗粒的动态响应。研究结论:通过建模和计算,将计算结果与已有试验结果相对比,验证了模型的正确性;在此基础上对铁路道床的振动特性进行分析,结果表明:动荷载作用下道砟之间的接触力按近似45°角的规律传递;相邻轨枕下方道砟颗粒的振动加速度和道砟接触力存在振动叠加作用,道砟颗粒的振动加速度、道砟接触力及道砟颗粒动位移随道床深度的增加而递减。

Research purposes： Railway ballast bed is a typical granular structure, thus with special focus on the distinct behavior of railway ballast, a spatial coupling sleeper - ballast model is established using the discrete element method. The researches are done on the railway ballast vibration behavior and the dynamic response of ballast granule through loading the dynamic time domain spectroscopy of high - speed train. Research conclusions：Through establishing the model and calculation, the model validation is verified by comparing the calculation results with the test results. Based on it, the analysis of the dynamic characteristics of railway ballast is made. The results show that the contact force between ballasts transfers as nearly 45°, and there exists a vibration superposition effect within the ballast under neighboring sleepers for the ballast vibration acceleration and ballast contact force. The ballast vibration acceleration, the dynamic displacement and the contact force are reduced as the depth of the ballast bed increases.