In winter, cold air flowing into tunnels undergoes heat exchange with the surrounding rock and lining, rendering frost protection a critical concern. In this paper, a practical procedure for integrating the FEM–CFD coupled method into probabilistic analysis is presented for determining the thermal insulation length demand of tunnels in cold regions, in which uncertainties in the air temperature and wind speed are considered. The results indicate that with ventilation implemented in the coldest month, tunnel temperatures gradually rise along the longitudinal direction, exhibiting a distinct temperature variation near the entrance. Based on the numerical simulation results obtained with 100 air temperature and wind speed samples, generated using the Monte Carlo method, the thermal insulation length demand of the tunnel ranges from 1000 to 1500 m, showing a distribution that follows the characteristics of a normal distribution. Additionally, a corresponding surrogate model is developed, and a thermal insulation failure probability model is proposed to analyze the sensitivity of meteorological parameters, revealing that the air temperature is the primary factor influencing the thermal insulation length demand. The findings of this research provide novel insights for the engineering community in designing resilient and sustainable tunnels in cold regions, mitigating the potential risks associated with freezing events and ensuring safe and efficient transportation infrastructure.

在冬季，流入隧道的冷空气与周围的岩石和衬砌进行热交换，因此防冻成为一个关键问题。本文提出了一种将 FEM-CFD 耦合方法与概率分析相结合的实用程序，用于确定寒冷地区隧道的隔热长度需求，其中考虑了气温和风速的不确定性。结果表明，随着最冷月份的通风，隧道温度沿纵向逐渐升高，且入口附近表现出明显的温度变化。根据蒙特卡罗方法对100个气温和风速样本进行数值模拟的结果，隧道保温长度需求范围为1000~1500m，分布符合正态分布特征。此外，还建立了相应的替代模型，并提出了隔热失效概率模型来分析气象参数的敏感性，揭示了气温是影响隔热长度需求的主要因素。这项研究的结果为工程界在寒冷地区设计弹性和可持续隧道、减轻与冰冻事件相关的潜在风险以及确保安全高效的交通基础设施方面提供了新颖的见解。