摘要
隧道人工冻结施工期地层的冻胀现象会对工程周边环境产生不良影响,合理的地表冻胀预测方法对隧道冻结设计和施工具有重要意义。为此,针对地铁双线隧道冻结施工期地表冻胀问题,考虑土体结冰温度,同时假设冻结管管壁温度恒定,采用单管冻结理论与平板冻结理论求解冻结锋面半径解析解。进而基于随机介质理论,考虑冻结壁发展过程,分别建立地铁双线隧道冻结壁交圈前后地表冻胀的历时预测模型,并采用Maple数学软件编制相应的数值计算程序,结合工程案例开展准确性分析,通过对比验证该预测模型的准确性,同时说明地表冻胀位移分析中考虑土体结冰温度及冻结壁平均温度的必要性。最后,采用因素分析法,分析3种隧道埋深(6,12,18 m)和4种隧道净距(0.25D,1.0D,2.0D,3.0D)条件下地表冻胀位移的演化规律。结果表明,随着隧道净距的增加,冻土层中产生的冻胀叠加效应逐渐减弱,双线隧道中心线处地表冻胀位移最大值逐渐减小,其形态存在由“双峰”型向“单峰”型转换的过程;当隧道净距恒定时,随着隧道埋深的增加,地表冻胀位移整体呈下降趋势,隆起形态由“单峰”型转为“双峰”型,且隧道埋深对于地表隆起形态的影响程度大于隧道净距。研究成果可为隧道冻结施工期地表冻胀的预测提供理论依据。
The ground frost heave effect produced during the artificial freezing construction of subway tunnelscould have adverse effects on surface buildings,making it more important to predict the ground frost heave displacement scientifically and reasonably.To solve the problem of ground frost heave during the freezing construction period of the subway twin-tunnel,considering the soil freezing temperature and assuming that the temperature of the freezing pipe wall is constant,the single pipe freezing theory and the plate freezing theory were used to calculate the freezing front radius.Then,based on the stochastic medium theory and the development process of the frozen wall,the prediction models of ground frost heave before and after the intersection of the frozen wall of the subway twin-tunnel were established,respectively.The corresponding numerical calculation codes were compiled by using Maple mathematical software.The accuracy of the prediction model and the necessity of considering the freezing temperature of soil and the average temperature of frozen wall in the analyzing ground displacement were verified by comparison with engineering cases.Finally,the evolution of ground frost heave under three tunnel depths(6,12,18 m)and four tunnel clear distances(0.25D,1.0D,2.0D,3.0D)was analyzed using factor analysis.The results show that the frost heave superposition effect in the frozen soil layer gradually weakens with an increase in tunnel clear distance,and the maximum value of ground frost heave at the centerline of the twin-tunnel gradually decreases,and its morphology changes from“double-hump”to“single-hump”;When the tunnel clear distance is constant,the overall trend of ground uplift decreases with the increase of tunnel depth,and the uplift morphology changes from“single-hump”to“doublehump”,and the influence of tunnel depth on ground uplift morphology is greater than that of tunnel clear distance.The research results can provide a theoretical basis for predicting ground frost heave during freezing co
作者
李孟凯
蔡海兵
洪荣宝
LI Mengkai;CAI Haibing;HONG Rongbao(School of Civil Engineering and Architecture,Anhui University of Science and Technology,Huainan 232001,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2023年第6期2198-2209,共12页
Journal of Railway Science and Engineering
基金
国家自然科学基金资助项目(51778004)
安徽省学术和技术带头人后备人选科研活动经费项目(2018H170)
安徽省2019年度高校学科(专业)拔尖人才学术资助项目(gxbjZD10)
安徽省高校研究生科学研究项目(YJS20210383)
安徽理工大学研究生创新基金资助项目(2020CX2024)。
关键词
隧道工程
冻胀预测
结冰温度
地表冻胀
冻结理论
随机介质理论
tunnel engineering
frost heaving prediction
freezing temperature
ground frost heave
freezing theory
stochastic medium theory
