基于离散元-有限差分耦合的摩擦型轨枕底部凹槽形状对有砟道床横向阻力的影响机理  

Impact mechanisms of frictional sleeper bottom groove shapes on lateral resistance in ballasted track beds based on discrete element-finite difference coupling approach

作　　者：沈泽涵 肖源杰 谭攀 姜钰 王萌 华文俊 张冲冲 SHEN Zehan;XIAO Yuanjie;TAN Pan;JIANG Yu;WANG Meng;HUA Wenjun;ZHANG Chongchong(School of Civil Engineering,Central South University,Changsha 410075,China;MOE Key Laboratory of Engineering Structures of Heavy Haul Railway(Central South University),Changsha 410075,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]重载铁路工程结构教育部重点实验室(中南大学),湖南长沙410075

出　　处：《中南大学学报（自然科学版）》2024年第10期3787-3802,共16页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(U1934209,52178443,51878673);中国铁道科学研究院科技研究开发计划重大课题(2020YJ022,2019YJ026);重载铁路工程结构教育部重点实验室(中南大学)开放课题(2021JZZ01,2021JZZ02,2022JZZ03);中南大学中央高校基本科研业务费专项资金资助项目(2023ZZTS0188)。

摘　　要：摩擦型轨枕可有效增强有砟道床横向阻力,但目前没有相关设计规范,摩擦型轨枕底部凹槽对横向阻力的增加机制尚不清晰。为深入分析不同凹槽形状对道床横向阻力的影响并揭示横向阻力的增强机理,基于横向阻力现场测试和离散元-有限差分耦合方法建立三维轨枕-有砟道床-路基数值模型,从宏、细观层面研究5种不同轨枕底部凹槽形状对横向阻力的影响。研究结果表明:与普通型轨枕相比,不同摩擦型轨枕的横向阻力增幅存在较大差异,范围为35.1%~80.2%,且横向阻力随凹槽侧面积的增加而呈对数增加;由于底部凹槽对道砟颗粒的约束作用,轨枕底部与道砟颗粒的接触数增加,凹槽附近的接触力增大,接触力链分布更密集;摩擦型轨枕周围颗粒的位移和旋转受到更强的约束;摩擦型轨枕各向异性在轨枕出现位移后向水平面转变,这是增强横向阻力的主要细观因素。建议在有砟轨道的设计中,采用具有不连续槽的摩擦轨枕,并考虑以最大化凹槽侧面积为目标进行设计。Frictional sleepers are proven to effectively enhance the lateral resistance of ballasted track beds.However,there are currently no relevant design standards,and the mechanism by which the grooves at the bottom of frictional sleepers increase lateral resistance remains unclear.To conduct a comprehensive analysis of the impact of different groove shapes on the lateral resistance of track beds and to reveal the mechanism for enhancing lateral resistance,a three-dimensional numerical model of the rail pad-ballast track bed-subgrade system was established using field tests for lateral resistance and a discrete element-finite difference coupled approach.This model was used to investigate the influence of five different shapes of grooves at the bottom of sleepers on lateral resistance at both the macro and micro levels.The results show that,compared to conventional rail pads,different frictional sleepers exhibit significant differences in the degree of increase in lateral resistance,ranging from 35.1%to 80.2%.Furthermore,the lateral resistance increases logarithmically with the increase in the groove's side area.The constraining effect of the bottom grooves on the granular particles of the track bed leads to an increase in the number of contacts at the bottom of the rail pad,resulting in higher contact forces near the grooves,and a denser distribution of contact force chains.The displacement and rotation of particles around the frictional sleepers are constrained.Anisotropy in the frictional sleepers transforms to the horizontal plane after rail pad displacement,which is a major micro-level factor in enhancing lateral resistance.In the design of ballasted rail tracks,it is recommended to design ballasted tracks using frictional sleepers with discontinuous grooves,and to prioritize maximing the groove's side area.

关 键 词：有砟道床 横向阻力 摩擦型轨枕 轨枕形状 离散元-有限差分耦合 

分 类 号：TU45[建筑科学—岩土工程]