This article discusses how using insulation materials in tunnels can prevent frost damage in cold regions. The researchers focused on how moisture can affect the insulation's ability to keep tunnels warm. When the air in the tunnel is humid, the insulation can absorb moisture over time. In cold tunnels, this trapped moisture can freeze, making the insulation less effective in keeping the tunnel warm. The study shows that high humidity can cause insulation materials to absorb moisture, which reduces their ability to insulate tunnels properly when frozen.