移动荷载下无砟轨道路基动应力和动位移研究  

Study on Dynamic Stress and Displacement of Ballastless Track Subgrade under Moving Loads

作　　者：刘刚 王立安[2] 罗文俊 余翠英[1,2] 李策 LIU Gang;WANG Lian;LUO Wenjun;YU Cuiying;LI Ce(School of Science,East China Jiaotong University,Nanchang 330013,China;Jiangxi Key Laboratory of Disaster Prevention-mitigation and Emergency Management,East China Jiaotong University,Nanchang 330013,China)

机构地区：[1]华东交通大学理学院,南昌330013 [2]江西省防灾减灾及应急管理重点实验室(华东交通大学),南昌330013

出　　处：《铁道标准设计》2024年第12期37-42,51,共7页Railway Standard Design

基　　金：国家自然科学基金项目(51978265);江西省防灾减灾及应急管理重点实验室项目(20212BCD42011);江西省自然科学基金项目(20212BAB211007)。

摘　　要：无砟轨道路基是承受上部轨道结构自重和列车动荷载的基础,移动荷载作用下路基内部应力应变状态的求解是路基动力学研究的关键。为准确计算移动列车荷载作用下路基的竖向动应力和动位移,建立CRTSⅢ型板式无砟轨道-路基-地基数值模型,改进轮轨激振力表达式,基于有限元软件荷载子程序二次开发实现了列车动荷载的模拟,并开展一系列的动力显式数值计算。研究结果表明:路基表面产生与轮轨力数量相对应的动力响应峰值,且最大值出现在第3个转向架荷载通过时刻;路基与混凝土底座板边缘接触位置产生应力集中,竖向动位移在轨道结构下方区域均匀分布;列车荷载引起的路基振动沿深度方向衰减并向轨道中心线位置叠加,在路基底面竖向动应力和动位移分别为8 kPa、0.89 mm;随着车速增加,路基动应力和动位移显著增大;增加路基高度能有效提升路基的荷载缓冲能力,但动位移和动应力的衰减趋势逐渐放缓。综合分析表明,底座板边缘位置和路堤中心区域的土体强度需要受到重视。The ballastless track subgrade is the foundation that bears the weight of the upper track structure and the dynamic train loads.Solving the internal stress-strain state of subgrade under moving load is a key aspect of subgrade dynamics research.To accurately calculate the vertical dynamic stress and displacement of the subgrade under moving train loads,a numerical model of the CRTSⅢ-type slab ballastless track-subgrade-foundation was established.The wheel-rail excitation force expression was improved and secondary development of the load subroutine within finite element software was used to simulate the dynamic train load.A series of dynamic explicit numerical calculations were carried out.The results showed that the subgrade surface generated dynamic response peaks corresponding to the wheel-rail forces,with the maximum value occurring when the third bogie load passed.Stress concentration occurred at the contact position between the subgrade and the concrete baseplate edge.The vertical dynamic displacement was uniformly distributed beneath the track structure;The vibration induced by the train load attenuated along the depth direction and superposed toward the track centerline.The vertical dynamic stress and displacement at the bottom of subgrade were 8 kPa and 0.89 mm,respectively.As train speed increased,the dynamic stress and displacement of the subgrade increased significantly.Increasing the subgrade height effectively improved its load buffering capacity,but the attenuation trend of dynamic displacement and stress gradually slowed down.Comprehensive analysis indicated that the soil strength at the baseplate edge and the central area of the embankment would require attention.

关 键 词：高速铁路 无砟轨道路基 移动荷载 二次开发 竖向动应力 竖向动位移 

分 类 号：U213.1[交通运输工程—道路与铁道工程] U238