It has recently been reported that under sleeper pads (USPs) could improve ballasted rail track by decreasing the sleeper settlement and reducing particle breakage. In order to find out what happens at the particle–pad interface, discrete element modelling (DEM) is used to provide micro mechanical insight. The same positive effects of USP are found in the DEM simulations. The evidence provided by DEM shows that application of a USP allows more particles to be in contact with the pad, and causes these particles to transfer a larger lateral load to the adjacent ballast but a smaller vertical load beneath the sleeper. This could be used to explain why the USP helps to reduce the track settlement. In terms of particle breakage, it is found that most breakage occurs at the particle–sleeper interface and along the main contact force chains between particles under the sleeper. The use of USPs could effectively reduce particle abrasion that occurs in both of these regions.

中文翻译：

---

使用箱测试对枕垫进行离散元建模。


最近有报道称，轨枕垫板 (USP) 可以通过减少轨枕沉降和减少颗粒破损来改善有碴铁路轨道。为了了解颗粒-垫界面上发生的情况，使用离散元建模 (DEM) 来提供微观机械洞察。在 DEM 模拟中也发现了 USP 的相同积极影响。 DEM 提供的证据表明，USP 的应用允许更多颗粒与垫板接触，并导致这些颗粒将较大的横向载荷传递到相邻道碴，但在轨枕下方传递较小的垂直载荷。这可以用来解释为什么 USP 有助于减少轨道沉降。在颗粒破碎方面，发现大多数破碎发生在颗粒-轨枕界面以及沿轨枕下方颗粒之间的主要接触力链。 USP 的使用可以有效减少这两个区域发生的颗粒磨损。