Thermal characteristics of tunnel in cold regions determine whether it will be affected by frost damage. Within this context, a series of key environmental factors were recorded by filed monitoring, such as temperature, wind speed and wind direction at tunnel site. The results demonstrate that environmental factors, topography and tunnel orientation codetermine the thermal characteristics inside the tunnel. In the coldest day, the temperature of air and tunnel structure distributed in the asymmetric parabola curve except surrounding rock. Meanwhile, the temperature of surrounding rock is always positive in the whole monitoring period, which varied slightly with season. The wind speed inside the tunnel is directly affected by that outside the tunnel, especially at ends of tunnel. With the distance increasing from tunnel entrance to the exit, the frost depth and frost index first decreased and then increased. Additionally, the temperature of all monitoring points in the same section increased with the distance from the sidewall to surrounding rock. This study can provide some information about the thermal characteristics and references for design and maintenance of the cold-regional tunnels.

寒冷地区隧道的热学特性决定了它是否会受到冻害的影响。在此背景下，通过现场监测记录了隧道现场温度、风速、风向等一系列关键环境因素。结果表明，环境因素、地形和隧道方向共同决定了隧道内的热特性。在最冷的一天，除了围岩外，空气和隧道结构的温度分布在不对称的抛物线曲线上。同时，在整个监测期内，围岩温度始终为正值，随季节变化略有变化。隧道内的风速直接受隧道外风速的影响，特别是隧道末端。随着隧道入口到出口距离的增加，霜冻深度和霜冻指数先减小后增大。此外，同一断面所有监测点的温度都随着井壁到围岩距离的增加而升高。本研究可为寒区隧道的热工特性和设计维护提供参考。