风沙区铁路有碴道床动力特性的离散元模拟及参数优化设计

项目名称： 风沙区铁路有碴道床动力特性的离散元模拟及参数优化设计

项目编号： No.50808027

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 严颖

作者单位： 大连交通大学

项目金额： 20万元

中文摘要： 本项目针对风沙环境下铁路有碴道床在列车往复荷载下的非均匀沉降和弹性降低现象，采用离散元方法对沙粒-道碴混合颗粒系统的动力特性进行了数值模拟。首先针对道碴颗粒的非规则形态，采用四元素法构造组合颗粒单元，并通过直剪试验进行了离散元数值模拟和试验验证；同时，重点讨论了不同的组合颗粒形态对剪切强度的影响。考虑到颗粒间滑动与滚动摩擦的共同影响，针对颗粒介质的滚动摩擦机理进行了深入研究，并通过滚动实验进行模型检验和参数确定。在风沙条件下，对不同配比下的沙石混合体的宏观弹性模量和沉降量进行了试验测试和数值模拟，重点分析了不同含沙量下沙-石混合体的力链强度和配位数分布规律，揭示了弹性模量随含沙量变化的微观内在机理。为更真实地模拟有碴道床的工作状态，设计了道碴箱试验，研究了道床的累积沉降量与含沙量的关系。

中文关键词： 有碴道床；离散元；弹性模量；沉降；含沙量

英文摘要： This project adopted the discrete element method to simulate the dynamic characteristics of sand-ballast mixtures, in order to explain the settlement and elasticity reduction of the ballasted railway track under the repeated train loading in a wind-blown sand environment. With respect to the irregularity of the ballast particle shape, the quaternion method was used to construct clumps of spheres to resemble the real shape of ballasts, and the direct shear test of limestone rubbles was simulated, and the effect of different particle shapes on the macro shear strength was disscussed. Considering the action of both sliding and rolling friction between particles, the mechanisms of rolling friction was explored and verified through rolling friction experiment. Under the wind-blown sand conditons, the macro elastic modulus and settlement of sand-ballast mixtures were measured and simulated with different sand contents. The force chain strength and cooridination number distribution of sand-ballast mixtures was analyzed, and the internal mechanism of the change of the elastic modulus with different sand contents was explored at the micro scale. Box tests were designed to model the ballasted railway track in real working condition, and the relationship between the accumulated settlement and sand contents were studied.

英文关键词： ballasted railway track;discrete element model;elastic modulus;settlement;sand content