高速铁路无砟轨道现浇道床混凝土冻融破坏机理及寿命预测
Freeze-thaw Damage Mechanism and Service Life Prediction of High-speed Railway Ballastless Cast-in-place Track Concrete
董昊良 1李化建 2杨志强 2温家馨 1黄法礼 2王振2
作者信息
- 1. 中国铁道科学研究院,北京 100081;中国铁道科学研究院集团有限公司铁道建筑研究所,北京 100081
- 2. 中国铁道科学研究院,北京 100081;高速铁路轨道系统全国重点实验室,北京 100081
- 折叠
摘要
部分严寒地区的高速铁路无砟轨道现浇道床存在冻融粉化的问题.为揭示高速铁路无砟轨道现浇道床混凝土的冻融破坏机理并预测使用寿命,本文基于毛细吸附、静水压和损伤断裂理论,采用有限元分析方法研究现浇道床混凝土的冻融破坏机理.研究发现,孔隙水的冻胀作用是导致现浇道床混凝土表层发生冻融粉化的主要原因,现浇道床混凝土在冻融环境下呈现出由道床的四周及边角向中间区域逐渐剥落粉化的规律.通过分析环境最低温度在-24～-3 ℃、混凝土的吸水率为0.2％～1.0％时现浇道床的冻融破坏程度,建立无砟轨道现浇道床混凝土的寿命预测模型,预测不同吸水率和不同最低环境温度下现浇道床混凝土的冻融寿命,以期为寒区无砟轨道现浇道床混凝土的抗冻设计提供参考.
Abstract
The ballastless cast-in-place track in some severe cold regions suffers from freeze-thaw pulverization.In order to reveal the freeze-thaw damage mechanism and further to predict the service life of ballastless cast-in-place track con-crete,in this paper,a finite element analysis method was used based on the capillary adsorption,hydrostatic pressure and damage fracture theory.The results show that the freeze-thaw effect of pore water is the main reason for the freeze-thaw pulverization of the surface layer of cast-in-place track bed concrete.Meanwhile,the surface freeze-thaw scaling firstly occurs in the edges and corners before developing to the center areas of ballastless cast-in-place track concrete un-der freeze-thaw conditions.By analyzing the degree of freeze-thaw damage to ballastless cast-in-place track under mini-mum environmental temperatures ranging from-24 ℃ to-3 ℃ and with concrete water absorption rates between 0.2％and 1.0％,this paper established a life prediction model for ballastless cast-in-place track concrete to predict the freeze-thaw life of ballastless cast-in-place track concrete under different water absorption rates and minimum ambient tempera-tures,aiming to provide reference for the freeze-resistant design of ballastless cast-in-place track concrete in cold re-gions.
关键词
高速铁路/道床板混凝土/冻融粉化/寿命预测Key words
high-speed railway/ballastless track concrete/freeze-thaw pulverization/service life prediction引用本文复制引用
基金项目
国家自然科学基金(U1934206)
中国铁道科学研究院集团有限公司科研项目(2021WR002)
出版年
2024
NETL
NSTL
万方数据