换填垫层对多年冻土地基水热分布状态的影响  

Effect of replacement cushion on water-heat distribution in permafrost foundation

作　　者：张军辉 曾宪璋 高峰 郑健龙[1,2] 盛岱超 ZHANG Junhui;ZENG Xianzhang;GAO Feng;ZHENG Jianlong;SHENG Daichao(Key Laboratory of Highway Engineering,Ministry of Education,Changsha University of Science&Technology,Changsha 410114,China;School of Transportation Engineering,Changsha University of Science&Technology,Changsha 410114,China;Qinghai Communications Holding Group Co.Ltd.,Department of Science and Information,Xining 810000,China;School of Civil&Environmental Engineering,University of Technology Sydney,NSW 2007,Australia)

机构地区：[1]长沙理工大学公路工程教育部重点实验室,湖南长沙410114 [2]长沙理工大学交通运输工程学院,湖南长沙410114 [3]青海省交通控股集团有限公司科技信息部,青海西宁810000 [4]悉尼科技大学土木与环境工程学院,悉尼NSW 2007

出　　处：《中南大学学报(自然科学版)》2025年第2期674-687,共14页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(52025085,52338009,52308438);国家重点研发计划项目(2021YFB2600900);国家博士后创新人才支持计划项目(BX20220259);湖南省自然科学基金资助项目(2023JJ40035);中国博士后面上基金资助项目(2023M730368);长沙市自然科学基金青年基金资助项目(kq2208234);公路养护技术国家工程研究中心开放重点基金资助项目(kfj220801)。

摘　　要：在气候环境变化和工程热效应背景下,青藏高原冻土地区道路病害频发、主动防控能力弱、养护管理机制不足等问题日益突出。换填垫层广泛应用于冻土公路工程设计与施工,在增强道路抗变形、抗冻害和稳定性方面发挥重要作用,但目前针对其在服役期内对地基水热分布状态的影响有待深入探讨。在青海共和—玉树高速换填垫层设计方案基础上,本文对细砂、砂砾和碎石这3种换填料下多年冻土地基水热分布进行数值试验,并以无换填粉质黏土为对照,研究换填垫层对地基水热分布及演变的影响规律。研究结果表明:换填碎石具有较好的控温性能,能够有效降低最大融化深度;换填垫层内未冻水含量显著降低,但引起未冻水沿换填-地基土接触面从地基外侧向中心横向流动;同时,换填加剧地表积水侵入深部地基土,在地形平坦且无主动排水条件下,深部地基土含水量及其振荡幅值逐年增长;换填料透水与导热性能是影响地基水热动态分布的关键因素,因换填引起的水热迁移不利于多年冻土地基力学性能长期保持,在工程实践中,应充分考虑路域气候环境及地形地貌特征,谨慎采用换填处理。Road problems in the frozen soil areas of the Qinghai—Tibet Plateau have become increasingly severe due to climate and environmental changes and engineering thermal effects,including frequent hazard occurrences,poor prevention and maintenance measures,etc.Replacement cushion is widely used in the design and construction of frozen road engineering,playing an essential role in enhancing deformation resistance,frost damage and stability.However,the effects of replacement cushions on the water-heat distribution during the service period have not been taken seriously.Based on the permafrost foundation replacement of the Gongyu—Yu Expressway,a numerical test on the water-heat distribution of the foundation was carried out with three types of filling materials,i.e.fine sand,coarse sand and gravel in the paper.The influence mechanism of filling materials on the distribution and evolution of water-heat was studied by using silty clay without replacement as a reference.The results show that replacing the gravel has better temperature control performance and can effectively reduce the maximum melting depth.Replacement cushions change the spatial and temporal distribution of foundation moisture.The unfrozen water content in the replacement layer decreases significantly,and the unfrozen water flows from both sides of the foundation to the centre along the filling-soil interface.The replacement cushion causes the surface ponding to invade into deeper soil.Especially without active drainage measures,the magnitude and oscillation amplitude of the water content in the deep foundation increase significantly.The water permeability and thermal conductivity of filling materials are important factors affecting water-heat distribution and evolution in road foundations.The moisture migration caused by replacement is not conducive to the long-term maintenance of the mechanical properties of the foundation.Therefore,replacement should be carefully adopted in engineering practice and on the premise of fully considering the climate envi

关 键 词：道路换填 冻土地基 模拟实验 水热分布 水分迁移 

分 类 号：TU411[建筑科学—岩土工程]