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。冻结与未冻结围岩模量比、初始地层含水率对隧道冻胀力存在一定程度的影响：冻结与未冻结围岩模量比与隧道冻胀力负相关，初始地层含水率与隧道冻胀力正相关。冻胀变形各向异性系数对冻胀力的大小与分布影响最大。同时，经过多年的冻融循环，不同初始地层含水率下衬砌外围的水分场差距缩小，导致初始地层含水率对第20年冻胀力的大小与分布影响最小。整体而言，隧道冻胀力的分布主要是温度场与衬砌几何之间博弈的结果：其中拱脚处最小的冻结深度导致该处冻胀力较小，但衬砌几何受力后顶拱与仰拱变形导致的拱脚弯曲折叠并向外侧围岩挤压，会增大拱脚处的压应力。因此，对于衬砌厚度较小的隧道而言，拱脚向外侧围岩挤压的效应更为明显，这导致拱脚处冻胀力较大。综合来看，寒区隧道的冻胀力分布需同时考虑温度条件、水分条件、围岩冻胀变形的各向异性、衬砌几何等因素的影响。

In cold regions， the frost heave of surrounding rock could lead to additional force on lining structures， 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 principles 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 monitoring result of the Qingshashan tunnel. Furthermore， the numerical model of the Dongtianshan tunnel was constructed， 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 volumetric water contents at the lining top and sides increased by 10.46% and 4.21%， respectively， and the volumetric 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 top arch and inverted arch are mainly manifested as compressive stress， while the compressive stress of the arch foot is minor and partially represented as tensile stress. The frost heave force distribution patterns under different minimum air temperatures， initial water contents， modulus ratios between frozen and unfrozen surrounding rock， and orthotropic coefficients of frost heave deformation are the same. Normal stress distributions outside the lining are “mushroom-shaped” as a whole. The decrease in temperature could extend the freezing area， and the increase of orthotropic frost heave deformation coefficient could concentrate frost heave strain’s direction， which could significantly promote the frost heave force. The modulus ratio between frozen and unfrozen surrounding rock was negatively related to frost heave force， and the initial water content was positively related to frost heave. The orthotropic coefficient of frost heave deformation has the most significant influence on the value and distribution of frost heave force. After 20 years of freeze-thaw cycles， the difference of water field under different initial formation water content reduced， which leads to the little difference in frost heaving force of the tunnel under different initial formation water contents. The frost heave force distribution is mainly the result of the competition between the temperature field and the lining geometry. The minimum freezing depth leads to the smallest frost heave force at the arch foot. However， the deformation of the lining causes the arch foot to press against the surrounding rock， which could increase the compressive stress on the arch foot. For the tunnel with a small lining thickness， the extrusion effect of the arch foot to the outer surrounding rock is more prominent， which leads to a more considerable frost pressure at the arch foot. Overall， the frost heave force distribution of tunnels in cold regions should consider the influence of temperature conditions， water conditions， anisotropy of surrounding rock frost heave deformation， and lining geometry.