Abstract:

The study of heat preservation methods for tunnels in cold region is very important. As a result, a unsteady heat transfer finite difference calculation model is established based on convectionconduction interaction; the heat preservation and insulation effect of surface and sandwich heat preservation and insulation layer on sections of tunnels with and without permafrost is calculated and analyzed respectively; and the antifreezing effect of heat preservation layer along longitudinal direction of tunnel is studied. The results show that: 1) The surface heat preservation and insulation layer has a good effect on tunnel section without permafrost, while the sandwich one has a good effect on tunnel section with permafrost; and the heat preservation and insulation effects of these two kinds of layers vary little. 2) The temperature behind the tunnel lining shows periodic variation due to the influence of wind temperature, and the temperature variation range decreases over years. It is proposed that the surface layer should be adopted preferentially; and economical comparison should be made in design phase. The results can provide reference for design of tunnels in cold region in the future.

Key words: cold region tunnel, unsteady, heat preservation and insulation layer, finite difference, temperature field