摘要
双块式无砟轨道道床板会出现早期开裂现象,该病害与轨道早期温度场分布特性有关。为明确轨道早期温度场分布特性,基于热工学原理和气象测试数据,考虑双块式无砟轨道的施工特点,建立早期温度场计算模型,并对早期温度场分布特性进行分析。结果表明:道床板浇筑完成后温度场呈先增加后减小的变化趋势,其最高温度约出现在第21 h时刻,且比日最高气温高10.6~12℃。道床板温度梯度沿着垂向呈线性分布,而沿横向呈明显的非线性分布特征,最大横向温度梯度出现在道床板与轨枕界面处,其值可达67℃/m。在该温度梯度荷载下,会出现道床板与轨枕界面早期开裂,随后应力集中转向轨枕角处,并进一步发展为道床板表面横向贯穿裂缝。
The track bed of ballastless track with double-block sleeper may experience early cracking,which is related to the early temperature of ballastless track.In order to clarify the distribution characteristics of early temperature and thermal-induced cracking mechanism,the early temperature calculation model is established based on thermodynamic principle and meteorological test data in consideration of the construction characteristics of bi-block slab track to analyze the distribution characteristics of early temperature field.The results indicate that the temperature increases rapidly and then decreases after the track bed is poured,and the maximum temperature appears at about 21 h and is 10.6~12℃higher than the daily maximum temperature.The temperature gradient of track bad is distributed linearly along the vertical direction,while it is distributed nonlinearly along the transverse direction.The maximum lateral temperature gradient appears at the interface of track bed and sleeper,and its value can reach 67℃/m.Under the action of temperature gradient,the ballastless track may suffer early cracking at the interface between track bed and sleeper.Then the stress concentration transfers to the sleeper corner and further develops into transverse penetration cracks.
作者
韩超
陈家豪
HAN Chao;CHEN Jiahao(Henan Technical College of Construction,Zhengzhou 450001,China;College of Civil Engineering,Henan University of Technology,Zhengzhou 450001,China)
出处
《铁道标准设计》
北大核心
2020年第10期41-47,共7页
Railway Standard Design
基金
河南省科技攻关计划项目(172102210285)
河南省高校基本科研业务专项(NSFRF170921)。
关键词
双块式无砟轨道
开裂机理
气象数据
水化热
温度场
热应力
ballastless track with double-block sleeper
cracking mechanism
meteorological data
hydration heat
temperature field
thermal stress
