CRTSⅡ型板式无砟轨道结构层间离缝机理研究  

Mechanism Analysis of Delamination of CRTSⅡSlab Ballastless Track Structure

作　　者：赵国堂[1,2,3] 刘钰 ZHAO Guotang;LIU Yu(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Department of Science,Technology and Information Technology,China Railway,Beijing 100844,China;Key Laboratory of High-speed Railway Engineering,Ministry of Education,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]中国国家铁路集团有限公司科技与信息化部,北京100844 [3]西南交通大学高速铁路线路工程教育部重点实验室,四川成都610031

出　　处：《铁道学报》2020年第7期117-126,共10页Journal of the China Railway Society

基　　金：国家自然科学基金(51708459,U1934206)。

摘　　要：板式无砟轨道结构层间界面为力学薄弱面,在温度和外荷载作用下,容易发生离缝。建立CRTSⅡ型板式无砟轨道多层薄板体系全过程三维渐进损伤力学模型,分析服役前界面损伤发生、发展过程和离缝机理,以及服役后考虑历史损伤和损伤累积效应下离缝的动态演化机制。结果表明:"单元→纵连(未服役)→服役"全过程中,轨道结构在正、负温度梯度,以及整体温升和列车"拍打"作用下,层间界面不同区域发生主拉伸型、混合型和主剪切型损伤。损伤累积导致层间离缝,离缝主要从主剪切型损伤区域开始,损伤和离缝发展存在继承性。单元状态下,温度梯度较小时界面即出现一定程度损伤,且损伤随温度梯度值的逐渐增大而不断发展,但实测温度梯度多在-40~90℃/m"安全温度梯度"范围内,此时离缝发生的可能性很小。纵连(未服役)状态下,"整体温升+正温度梯度"为最不利荷载组合。在整体温升条件下,层间界面离缝产生对应的正温度梯度值显著降低。服役状态下,受列车循环冲击荷载作用,若承轨台下存在既有离缝,轨道板将"拍打"CA砂浆层,离缝发展成"花生壳状"。随着冲击次数的不断增加,离缝继续发展。Due to mechanically weak interfaces between the layers of slab ballastless track structure,delamination can easily happen under temperature and external load.In this paper,a three-dimensional progressive damage mechanical model of the multi-layer slab system of CRTSⅡslab ballastless track,was established to analyze the occurrence,development process of the interface damage and mechanism of delamination before the slab ballastless track being put into service,as well as the dynamic evolution mechanism of delamination after coming into service,considering historical damage and cumulative damage effect.The results show that there are three different types of damage,such as tensile damage,mixed damage and shear damage.They occur in different areas of interface between track slab and CA mortar layer under the effect of positive/negative temperature gradient and track slab slapping on CA mortar layer,when the track structures are coming from unit status to longitudinal connected status(not in service)and then to the service status.The damage accumulation leads to the delamination,which mainly starts from the main shear damage area.There is inheritance between damage and the development of delamination.Some interface damage happens in unit status of track structure,owing to a small temperature gradient,and it grows with the increasing value of temperature gradient.However,the actual temperature gradient is almost within the scope of-40-90℃/m,called“safe temperature gradient”under the act of which there is a little chance of delamination.When unit track structures are longitudinal connected but not in service,overall temperature rise and positive temperature gradient are the most adverse combination of loads to delamination.Under the condition of overall temperature rise,the value of positive temperature gradient,corresponding to delamination,decreases significantly.When longitudinal connected track structure comes in service and there is delamination under rail bearing platform,the track slab will“slap”on CA

关 键 词：板式无砟轨道 层间界面 内聚力模型 离缝 渐进损伤分析 

分 类 号：U213.244[交通运输工程—道路与铁道工程]