冻融作用下多年冻土隧道结构及围岩变形规律  

Deformation rules of surrounding rock and the structure of permafrost tunnels under freeze-thaw cycles

作　　者：夏才初[1,2] 白雪莹 韩常领 XIA Caichu;BAI Xueying;HAN Changling(College of Civil Engineering, Tongji University, Shanghai 200092, China;College of Civil Engineering, Shaoxing University, Shaoxing 312000, China;CCCC First Highway Construction Co., Ltd., Xi′an 710075, China)

机构地区：[1]同济大学土木工程学院,上海200092 [2]绍兴文理学院土木工程学院,浙江绍兴312000 [3]中交第一公路勘察设计研究院有限公司,陕西西安710075

出　　处：《哈尔滨工程大学学报》2020年第7期1016-1021,共6页Journal of Harbin Engineering University

基　　金：国家自然科学基金面上项目(51778475,41472248);国家科技支撑计划(2014BAG05B05)。

摘　　要：为研究多年冻土隧道结构、围岩的冻融变形规律以及含水量对隧底围岩冻融循环次数和变形的影响,本文采用有限元方法进行数值模拟,采用热-力场耦合计算隧道、围岩的传热变形过程。计算结果表明:在运营期内,隧底冻土围岩及路面的融沉位移逐年减小,总体呈现向上回升趋势;冻结期隧底围岩的回冻变形减轻了融沉变形导致的隧道不均匀变形程度,因此应重点控制施工期内隧底围岩的融化沉降,加强隧底保温措施以减少围岩在运营期所经历的冻融循环次数;冻土围岩含水量越高,运营期内隧底冻土回冻速度越快,隧底围岩含水量超过27%时,融沉所导致的路面横向不均匀融沉变形将对路面的排水带来不利影响。To analyze the deformation rules of surrounding rocks and structures in permafrost tunnels under freeze-thaw cycles,as well as the effect of water content on the frequency of freeze-thaw cycles and the deformation of surrounding rocks under the tunnel,the finite-element method is applied to a numerical simulation in this study.By calculating the heat transfer and deformation process of the tunnel and surrounding rocks using thermomechanical coupling,results show that,during the operation period,the thaw settlement of pavement in the tunnel and permafrost under the tunnel has decreased year by year,whereas the total deformation trend of the tunnel is upward.The refreezing deformation of permafrost under the tunnel in the freezing period has alleviated the inhomogeneous deformation caused by thaw settlement.Therefore,measures should be taken to control the thaw settlement during the construction period,and the insulation measures should be strengthened in the tunnel invert to reduce the frequency of freeze-thaw cycles for surrounding rocks in the operation period.The more the water content in the permafrost,the faster the refreezing speed in the operation period.Once the water content of rocks under the tunnel exceeds 27%,the inhomogeneous deformation of pavement caused by thaw settlement could threaten the pavement drainage.

关 键 词：隧道 多年冻土 冻融循环 围岩 变形 含水量 数值模拟 

分 类 号：U459.2[建筑科学—桥梁与隧道工程]