水热力耦合下公路隧道结构各向异性冻胀力分布特征研究  

Orthotropic frost heaving force distribution characteristics for tunnel structures under hydro-thermo-mechanical coupling

作　　者：陆许峰 黄解放 张锋[1] 冯德成[1] LU Xufeng;HUANG Jiefang;ZHANG Feng;FENG Decheng(School of Transportation Science and Engineering,Harbin Institute of Technology,Harbin 150090,China;CCCC First Public Bureau Group Co.,Ltd.,Beijing 100024,China)

机构地区：[1]哈尔滨工业大学交通科学与工程学院,黑龙江哈尔滨150090 [2]中交一公局集团有限公司,北京100024

出　　处：《冰川冻土》2023年第5期1522-1535,共14页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金项目(42171128,41971076);新疆维吾尔自治区重大科技专项(2018A03003-4)资助。

摘　　要：寒区围岩的冻胀会对衬砌结构带来附加荷载,威胁着衬砌结构的耐久性与安全性。为了研究季节冻土区隧道冻胀力的分布特征,基于能量守恒与质量守恒基本原理,建立了考虑正交各向异性冻胀变形的正冻围岩水-热-力耦合模型;结合青沙山隧道冻胀力的监测结果,验证了隧道冻胀力模型的可靠性。进而,针对东天山特长隧道的抗冻需求,构建了相应的隧道冻胀数值模型,对东天山隧道的温度场、水分场与冻胀力分布特征进行了研究,并分析了最低气温、初始地层含水率、已冻与未冻围岩模量比、冻胀变形各向异性系数对冻胀力分布的影响。东天山隧道冻胀的数值仿真结果表明:隧道的冻结深度分布并不均匀,在拱脚处最小,仰拱中心处最大,两处冻结深度相差48 cm。冻结范围的差异分布主要为拱脚处几何曲率较大,冷量需辐射至更广的空间所致。同时,由于拱脚处冻深最小,且拱脚的几何曲率较顶拱与仰拱更大,导致衬砌的拱脚处弯曲折叠最大,von Mises应力最大。单个冻融周期内,隧道冻深范围内围岩的含水率可分为冻结、融化、滞水、滞水消散共4个阶段。随着冻融循环次数的增加,拱顶与拱侧的滞水阶段体积含水率分别升高了10.46%与4.21%,拱脚与衬砌底部的滞水阶段体积含水率略有降低。围岩的冻胀对衬砌同时产生了法向应力与切向应力,其中顶拱、仰拱主要体现为压应力,拱脚的压应力较小且局部体现为拉应力。不同最低气温、初始地层含水率、冻结与未冻结围岩模量比、冻胀变形正交各向异性系数下的冻胀力分布模式相同。其中衬砌外围的法向应力整体呈“蘑菇形”。最低气温的降低、冻胀变形正交各向异性系数的增大,分别通过增大冻结范围与促进冻胀应变方向集中化,最终导致隧道冻胀力整体数值的增大,两者对隧道冻胀力影响显著。冻结与未冻结�In cold regions,the frost heave of surrounding rock could lead to additional force on lining struc⁃tures,which impairs the durability and safety of tunnels.This paper analyzed the distribution characteristics of tunnels’frost heave force in seasonally frozen regions.Firstly,energy conservation and mass conservation prin⁃ciples were introduced,and a hydro-thermal-mechanical coupling model of frozen surrounding rock considering orthotropic frost heaving deformation was constructed.The reliability of the model was verified with the monitor⁃ing result of the Qingshashan tunnel.Furthermore,the numerical model of the Dongtianshan tunnel was con⁃structed,and distribution characteristics of temperature fields,water fields,and frost heave force were studied.In addition,various influencing factors on the tunnel’s frost heave force were analyzed,including the minimum temperature,the initial formation water content,the modulus ratio of the frozen and unfrozen surrounding rock,and the orthotropic frost heave coefficient.The simulation results show that the frozen depth of the tunnel is not uniform,the smallest at the arch foot and the largest at the center of the inverted arch.The maximum frozen depth difference was 48 cm.The frozen depth difference was due to the largest geometric curvature at the arch foot.At the same time,due to the minimum freezing depth and largest geometric curvature at the arch foot,the bending and folding of the arch foot of the lining are the most significant,and the von Mises stress at the arch foot is the largest.During one freezing-thawing period,the water content change includes four stages:freezing,thawing,stagnating and dissipating.After 20 freeing-thawing periods,in the water stagnating stage,the volu⁃metric water contents at the lining top and sides increased by 10.46%and 4.21%,respectively,and the volumet⁃ric water contents at the arch foot and lining bottom decreased slightly.The frozen surrounding rock produced both normal and tangential stress on the lining.Among them,the

关 键 词：季节冻土区 隧道工程 冻胀力分布 正交各向异性冻胀 水-热-力耦合 

分 类 号：P642.14[天文地球—工程地质学] U451.2[天文地球—地质矿产勘探]