隧道内双块式无砟轨道早期湿度场分析  

Study on Early Humidity Field of the Bi-block Ballastless Track in Tunnel

作　　者：乔丽梅 曹世豪 QIAO Limei;CAO Shihao(School of Architectural Engineering,Zhengzhou University of Industrial Technology,Zhengzhou 450001,China;College of Civil Engineering,Henan University of Technology,Zhengzhou 450001,China)

机构地区：[1]郑州工业应用技术学院建筑工程学院,郑州450001 [2]河南工业大学土木工程学院,郑州450001

出　　处：《铁道标准设计》2022年第8期77-83,共7页Railway Standard Design

基　　金：国家自然科学基金项目(51908197);河南省科技攻关项目(202102310262);河南省高等学校重点科研项目(20B580001)。

摘　　要：双块式无砟轨道早期开裂与湿度分布有关。为了获取轨道早期湿度场分布特性,提出基于温度场模块的混凝土湿度场计算方法,开展密闭混凝土水化自干燥试验验证计算方法的可行性。建立了双块式无砟轨道早期湿度场计算模型,设计的稳态-瞬态-瞬态三步计算流程实现了施工顺序对早期湿度场的影响,并对大气干燥、水化自干燥、养护方法等因素的影响进行分析。结果表明:隧道基础湿度在顶部大气干燥和底部自由水浸润下达到平衡后沿深度呈指数分布。轨枕经60 d养护后湿度峰值降至81.1%。由于施工阶段轨道各部件湿度分布的差异性,会在道床板浇筑完成后于界面处形成较高的湿度梯度。随后在自然养护阶段的大气湿度日波动对轨道表层的影响深度为14 mm。最终,整个轨道结构湿度场在水化自干燥、湿度扩散及暴露面大气干燥等因素的持续影响下趋于平稳。The early cracks of bi-block ballastless track are related to the humidity distribution. In order to obtain the early humidity field distribution, the calculation method of concrete humidity field is proposed based on the temperature field module, and the self-desiccation test of closed concrete is carried out to verify the feasibility of the calculation method. The early humidity field calculation model of bi-block ballastless track is established, and the three-stage calculation method including steady-state analysis, transient analysis and transient analysis is designed to realize the influence of the construction sequence on the early humidity field. Then the effects of atmospheric drying, self-desiccation and curing method are analyzed. The results show that, the tunnel foundation humidity along the depth follows the exponential distribution law when reaching equilibrium under the combined action of top atmospheric drying and bottom water soaking. After 60 days of curing, the peak value of sleeper humidity drops to 81.1 %. Because of the difference of humidity distribution of each track component in the construction stage, the high humidity gradient will be formed at the interfaces after the casting of the track slab. Then the influence depth of the diurnal atmospheric humidity fluctuation on the track surface is 14 mm in the natural curing stage. Finally, the humidity field of the entire track structure tends to be stable under the continuous action of the self-desiccation, humidity diffusion and atmospheric drying on the exposed surface.

关 键 词：无砟轨道 早期开裂 湿度场 施工顺序 自干燥 大气湿度 

分 类 号：U213.244[交通运输工程—道路与铁道工程]