往复荷载下铁路道砟沉降特性的扩展多面体离散元分析

摘要

基于 Minkowski Sum 方法，采用扩展多面体单元构造非规则的道砟颗粒，对道砟材料在往复荷载作用下的动力特性进行离散元分析，研究其沉降量和形变刚度的演变过程。结果表明，在往复荷载作用下道砟材料的累计沉降量在变形初期增加显著，随着往复荷载次数的增加趋于稳定，其有效刚度在累计变形过程中不断增大并最终趋于平稳。本文研究表明，扩展多面体单元可有效模拟道砟材料的力学行为，研究其在列车往复荷载下的动力特性。%Based on the Minkowski Sum method,this paper introduced dilated polyhedral element to describe the irregular geometry of ballast particles and conducted discrete element analysis on the dynamic characteris-tics of ballast material under cyclic loading to study the evolution of the settlement and deformation stiffness of ballast material.The results showed that the accumulative settlement of ballast material under cyclic loading increased significantly at the early stage of deformation and then tended to be stable with the increase of the fre-quency of cyclic loading.Meanwhile,the effective stiffness during the accumulative deformation process of bal-last material also increased continuously and eventually became stable.Thus,this dilated polyhedral element can model the mechanic behaviors of ballast material effectively and reveal its dynamic characteristics under cy-clic loading of train.