摘要
论文考虑有砟轨道道床结构中底层道砟颗粒会逐渐侵切土质路基上表层的实际情况,引入基于双曲线函数的土阻力公式,发展了离散元颗粒与有限元网格体内耦合的接触力算法,建立了考虑道砟颗粒侵切路基表层的有砟轨道离散元-有限元耦合模型.其中道床中的非规则形状道砟采用离散元镶嵌单元构造,路基采用有限元20节点六面体实体单元构造.分析了道砟侵切路基下列车荷载及路基软硬程度对道床整体沉降的影响,绘制了有砟道床-路基的横截面应力及位移云图.研究表明提出的耦合模型不仅能反映道床自身的弹性变形和累积塑性变形,还能真实反映底层道砟侵切软土路基表层所导致的侵切沉降,为深入了解有砟道床的沉降劣化机理提供重要借鉴作用.
Considering the penetration phenomena between the ballast layer and the soil subgrade,the soil resistance using hyperbolic function is applied to the ballast penetrated into the subgrade surface.A coupled discrete-finite element model of ballasted railway track is established based on the proposed transfer algorithm of contact force between the discrete sphere and the hexahedron element.The ballast granules with irregular shapes are constructed using the clump model in the discrete element method(DEM),and the soil subgrade is modeled using the 20-node hexahedron solid element in the finite element method(FEM).The effects of traffic load and subgrade stiffness on the settlement of the ballasted track are analyzed.The stress and displacement contours are drawn in the cross section of the model.It is found that the proposed coupling model can not only present the elastic and cumulative plastic deformation of the ballast layer itself,but also reflect the settlement caused by the penetration of the bottom ballast into the soft subgrade surface.The increase of train load will aggravate the plastic deformation and the penetration settlement of the ballast layer.Meanwhile,the influence of subgrade stiffness on the soil resistance applied to the invading ballast can be represented by the ultimate standard value of soil resistance.The decrease of this ultimate standard value will also aggravate the penetration settlement.The study can provide an important insight for understanding the settlement and degradation mechanism of ballasted rail track.
作者
黎旭
严颖
季顺迎
Xu Li;Ying Yan;Shunying Ji(State Key Laboratory of Structural Analysis of Industrial Equipment,Dalian University of Technology,Dalian,116024;School of Civil Engineering,Dalian Jiaotong University,Dalian,116028)
出处
《固体力学学报》
CSCD
北大核心
2021年第4期407-419,共13页
Chinese Journal of Solid Mechanics
基金
国家自然科学基金项目(11572067,11872136)资助。
关键词
有砟道床
道砟侵切作用
离散元-有限元耦合
累积沉降
ballasted track
ballast penetration
coupled discrete-finite element method
accumulated settlement
作者简介
通讯作者:严颖.Tel:13332286972,E-mail:yyan@djtu.edu.cn.
