循环荷载作用下道砟破碎老化的离散元仿真

DEM Simulation of Ballast Degradation and Breakage under Cyclic Loading

为从细观力学上反映道砟与轨枕的相互作用机理以及道砟颗粒的破裂过程,建立了道砟-轨枕离散单元模型,对循环荷载作用下道砟破碎老化进行了仿真.道砟由不规则圆盘簇组成,分为不可破裂与可破裂颗粒,并施加单调荷载和循环荷载.结果表明:相同荷载下,加载时轨枕与道砟的接触力大于卸载时;破碎道砟颗粒集中在轨枕下方,道砟颗粒破裂产生的沉降是造成轨枕沉降的主要原因,沉降量随道砟颗粒强度的降低而增大.

In order to reflect the micro-mechanism of ballast-sleeper interaction and the process of ballast breakage,a 3-D ballast-sleeper model based on the discrete element method（DEM） was established,and ballast degradation and breakage under cyclic loading were simulated.In this model,irregular ballast particles are modeled by clusters,they are divided into two kinds,i.e.,unbreakable and breakable,and ballast is respectively subjected to monotonic and cyclic loads.The research results show that under the same load,contact force between ballast and sleeper is larger when the ballast is loaded than that when it is unloaded.The crushed clusters mainly appear underneath the sleeper,particle crushing is a major factor for sleeper settlement,and the sleeper settlement increases when ballast strength reduces.