预应力微型桩动态调控软岩路基上拱效果研究  

Effect of dynamic regulation of prestressed micro-piles on upheave of soft rock roadbeds

作　　者：张锐[1,2] 张喜伟 罗辉[1,3] 余雷 刘正楠 ZHANG Rui;ZHANG Xiwei;LUO Hui;YU Lei;LIU Zhengnan(School of Traffic and Transportation Engineering,Changsha University of Science&Technology,Changsha 410114,China;State Key Laboratory of Green and Long Life Road Engineering in Extreme Environments,Changsha University of Science and Technology,Changsha 410114,China;Hunan Zhonghe Geotechnical Engineering Co.,Ltd.,Changsha 410003,China;China Railway Economic and Planning Research Institute,Beijing 100038,China;Hunan Communications Research Institute Co.,Ltd.,Changsha 410015,China)

机构地区：[1]长沙理工大学交通运输工程学院,湖南长沙410114 [2]长沙理工大学极端环境绿色长寿道路工程全国重点实验室,湖南长沙410114 [3]湖南中核岩土工程有限责任公司,湖南长沙410003 [4]中国铁路经济规划研究院有限公司,北京100038 [5]湖南省交通科学研究院有限公司,湖南长沙410015

出　　处：《铁道科学与工程学报》2025年第3期1052-1063,共12页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(52278432);中国国家铁路集团有限公司科技研究开发计划项目(K2019G045)。

摘　　要：为研究并提出一种经济有效调控红层软岩路基上拱变形的工程措施并揭示其作用机理,自研可动态调节上拱变形的预应力微型桩试验装置,室内测得不同预应力(50、100、150和200kN)与桩顶竖向位移的关系,通过数值模拟计算分析桩径D为0.17 m的单桩(桩长8、10和12 m)与群桩(桩间中心距3D、4D、5D、6D)调控红层软岩路基上拱变形的效果与机制。室内试验结果表明,预应力微型桩可有效控制上拱变形,但控制能力并非随预应力的增加而线性增加,需实时监测上拱变形值,并动态调整预应力。数值模拟结果表明,无处治措施的工况下,试验路段因湿化作用和侧向地应力引起的上拱变形量约为9.5 mm;8、10和12 m长的预应力微型桩单桩调控下,上拱变形分布曲线在成桩位置出现突变,数值急剧减小,桩长和预应力的增加可使调控范围出现小幅度的增加,调控范围的最大值在2~3倍桩直径范围内波动;在试验选取的桩长和桩距范围内,12 m桩长、5D桩距的预应力群桩可同时兼顾安全性和经济性,使轨道附近上拱变形量分别减小至3.2mm(降幅为66.3%)、2.9mm(降幅为69.5%)和3.5mm(降幅为63.5%),最终满足规范对上拱变形量的控制要求;此外,群桩在施加预应力后调控能力明显增强,达到无预应力条件下的1.4倍左右。研究成果可为高速铁路红层软岩路基上拱处治提供参考。In order to propose an engineering measure to economically and efficiently regulate the heave deformation of red-layered soft rock roadbeds and to reveal the mechanism.The relationship between different prestresses(50,100,150,and 200 kN)and the vertical displacement of pile tops was measured indoors by using a self-developed test device with dynamically adjustable heave deformation.Numerical analyses were conducted to study the effect of single piles(with pile lengths of 8,10,and 12 m)and pile groups(with pile spacings of 3D,4D,5D,and 6D)in regulating the heave deformation of red-layered soft-rock roadbeds,when the pile diameter D is 0.17 m.Indoor test results indicate that the prestressed micropiles can effectively control heave deformation.However,the control capacity does not increase linearly,therefore necessitating real-time monitoring of the heave deformation values and dynamic adjustment of the prestressing force.Numerical simulations reveal that,under the working condition without any treatment measures,the heave deformation of the test section due to wetting effect and lateral ground stress is about 9.5 mm.The heave deformation distribution curve decreases sharply at the pile-forming position for 8 m,10 m,and 12 m long prestressed micropiles under single pile regulation.The increase of pile length and prestressing can cause a small increase in the regulation range,and the maximum value of the regulation area fluctuates in the range of 2~3 times the pile diameter.Prestressed pile groups with 12 m length and 5D spacing can balance safety and economy,reducing the heave deformation near the track to 3.2 mm(a decrease of 66.3%),2.9 mm(a decrease of 69.5%),and 3.5 mm(a decrease of 63.5%),ultimately meeting the specification requirements for heave deformation control.The regulation ability of pile groups is significantly enhanced after applying prestressing,reaching about 1.4 times that of the unprestressed condition.The research results can provide a reference for addressing the heave of red-layer soft rock ro

关 键 词：预应力微型桩 红层软岩 高铁路基 上拱变形 

分 类 号：TU43[建筑科学—岩土工程]