风沙影响下铁路道碴变形模量的离散元数值分析

针对风沙区有碴铁路道床的结构特性,对其在细沙贯入下的有效变形模量研究有助于理解风沙影响下的道床动力特性。采用离散单元模型对道碴碎石和细沙颗粒进行数值建模,并对不同含沙率γ下的有效变形模量进行了数值分析。结果表明,在低含沙率下(γ<30%)沙石混合体的变形模量基本保持不变,在高含沙率下(γ>30%),变形模量随含沙率的增加呈线性降低,以上变形模量随含沙量的变化规律与试验结果相一致。基于离散单元模型的数值模拟,在细观尺度上对沙石混合体的力链强度、空间分布及配位数进行了分析,揭示了沙石混合体有效变形模量随含沙量变化的内在机理。本文工作对风沙区有碴铁路道床力学行为的研究具有一定的借鉴意义,有助于促进风沙影响下有碴铁路道床的结构设计和沙害治理。

Discrete element analysis of elastic modulus of railway ballasts in wind with different sand contents

Investigation on elastic modulus of railway ballasts in wind with different sand contents can be benefited to understand the dynamic characteristics of railway track in wind-blown sand areas.In this study,discrete element models are developed,and elastic modulus is calculated of ballasts in wind with different sand contents γ.The results show that elastic modulus remains a constant with low sand contents(γ<30%),and decreases linearly with increasing sand contents with high sand contents(γ >30%).The simulation results agree with the experimental results.The internal mechanism of the relationship between elastic modulus and different sand contents is analyzed in terms of the strength and the spacial distribution of the force chains,and the coordination number of ballast-sand mixtures.The present study can be helpful for the understanding of the dynamic properties of ballasted railway tracks in wind-blown sand areas,and for the structure design and sand disaster treatments of ballasted beds.