铁路有砟道床振动和变形的离散元模拟与试验验证

Discrete element simulation and its validation on vibration and deformation of railway ballast

运用三维激光扫描仪获取碎石道砟颗粒的几何形态,构建了不规则形状的簇颗粒模型,在此基础上建立了有砟道床三维离散元模型,用于道床细宏观力学行为的离散元模拟分析。同时,为了验证离散元模拟结果的可靠性,开展了高速铁路有砟轨道1:1实尺模型试验,获得了静态加、卸载和循环简谐荷载作用下道床的变形以及不同深度处道砟的振动响应。对比分析表明,离散元模拟和试验获得的道砟振动加速度幅值接近,随深度的衰减规律一致;等效静态加、卸载条件下道砟的垂向变形以及循环荷载作用下道砟的累积变形均能够与试验结果吻合,说明建立的三维道床离散元模型是合理的,能够较为准确地模拟有砟道床的振动响应和累积变形行为,可用于高速铁路有砟道床的细、宏观劣化机制研究。

A three-dimensional（3D） discrete element model（DEM） is established to simulate micro-and macro-scale mechanical behaviors of railway ballast. In this model, the clump models with irregular shape are built to simulate the real ballast particle geometry morphology captured by using a 3D laser scanner. A full-scale model of high-speed railway ballasted track is conducted to validate the DEM model. The deformation and vibration response of railway ballast are obtained under the static load and the cyclic load in the laboratory. The amplitudes of the ballast acceleration and its attenuation law with the depth acquired by DEM simulation and experimental tests are close. Numerical results of the vertical deformation of railway ballast under the static loads and the permanent deformation under cyclic loads are good agreement with experimental data, which demonstrates that the established DEM model is reasonable. Therefore, the obtained vibration response and deformation of railway are reliable and relatively accurate. This DEM model can be used for subsequent analysis on the micro-and macro-mechanical behaviors and deformation of high-speed railway ballast.