高速列车重复荷载作用下道砟材料压密性及破碎规律研究

项目名称： 高速列车重复荷载作用下道砟材料压密性及破碎规律研究

项目编号： No.51508270

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 建筑科学

项目作者： 边疆

作者单位： 南京工业大学

项目金额： 20万元

中文摘要： 铁路基床在高速列车重复荷载下产生不可恢复的累积变形，由于道砟的碎化和路基不均匀沉降引起的过大的变形带来了高频率和昂贵的养护、维修。因此，正确理解轨下基础结构荷载传递机理和各结构层变形是安全、经济的轨道设计和优化养护、维修方案的关键要素。本项目针对列车重复荷载下道砟的碎化和压密性的宏、细观问题展开研究，首先，建立道砟颗粒离散元模型，实现道砟颗粒破碎和表面形态的数值模拟；其次，基于室内动三轴试验和动三轴试验离散元数值模型，分析影响颗粒碎化的因素，得出道砟微观力学参数与宏观压密性的关系；基于1:1模型试验和离散元数值模型，得出考虑颗粒碎化和路基不均匀沉降条件下的累积变形计算公式；最后，利用数值模型，分析轨道结构中道砟颗粒碎化的分布规律，基于对道砟破碎影响因素的研究，从道砟材料设计和轨道结构设计方面提出防治道砟破碎的技术方法。

中文关键词： 压密性；道砟；碎化；离散元；散粒体

英文摘要： The permanent deformation of subgrade was produced under high-speed train under repeated load.Due to the breakup and ballast subgrade uneven settlement caused by excessive deformation brings high frequency and expensive maintenance and repair. Therefore, the correct understanding of the load transfer mechanism of foundation under rail structure and the structure layer deformation is the key factor of security and economy track design and optimization of maintenance and repair scheme. This project aims at ballast breakup and compaction of the macroscopical and mesoscopic problems under repeated loading of train. First, the discrete element model of ballast particles will be established to realize numerical simulation of ballast particle breakup and surface morphology; Secondly, the influence of particle breakup factors will be analysed based on the dynamic triaxial test and discrete element numerical model, the relationship between mechanical parameters and micro macro compaction of ballast will be summarized; the particle breakup and subgrade uneven settlement calculation formula of deformation conditions will be summarized based on the 1:1 model test and discrete element numerical model; Finally, by using the numerical model, the ballast particles broken distribution regularity in track structure will be analysed; Based on the research on Influencing factors of the ballast breakup, the technological method of preventing ballast breakup will be proposed in the aspects of material design and structural design of ballast track.

英文关键词： compactibility;ballast ;breakup;discrete element method; granular materials