离散元-有限差分耦合法在铁路有砟道床研究中的应用

摘要

将离散元-有限差分耦合算法引入铁路有砟道床结构的力学分析中。通过激光扫描法建立了基于真实道砟颗粒外形的离散单元数值模型，以此对由碎石道砟所组成的散体道床进行精细化模拟；采用有限差分法对连续介质的轨枕及轨下路基基础进行仿真。通过在层间结构边界处设置虚拟耦合过渡层，并将力和位移作为媒介物理量于一个时间步内在两种程序之间进行交互迭代的方式实现了两种数值分析方法的动态耦合。在此基础上建立了轨枕-散体道床-路基的离散元-有限差分耦合数值模型。并通过现场实测结果验证了模型的正确性。%The discrete element method (DEM)and finite difference method (FDM)coupling algo-rithm was introduced into mechanical analysis of railway ballast bed structure in this paper.The ballast bed model which consists of crushed stones was well performed based on DEM simulation of realistic appearance of ballasts by laser scanning.Both sleeper and roadbed foundation of suc-cessive medium were simulated based on FDM.Virtual coupling transition layer was established between interlayer structure boundaries.The DEM and FDM were dynamic coupled through ex-changing and iterating the physical parameters of forces and displacements between the two soft-wares within each time step.The sleeper-ballast bed-roadbed foundation system EDM-FDM cou-pling simulation model was established depending upon the improved method,which had been validated with the field measured results.