Numerical simulations of heat transfer with ice–water phase change occurring in porous media and application to a cold-region tunnel

• A “three zone” model was presented to calculate the temperature field in porous media.
• The model was successfully verified by comparing its results to an analytical solution and by matching field data.
• Parameter a was found to be very important to the distribution of temperature in the porous media.
• The released latent heat makes the distribution of temperature change greatly.
• Paving insulation layer on the surface of second lining is a useful method to prevent tunnel from freezing–thawing damage.

To calculate the temperature field distribution with ice–water phase change occurring in porous media, a simple but effective method was presented. It was realized in terms of the “three-zone” theory (frozen zone, freezing zone and unfrozen zone), and by adjusting the parameters of unfrozen water content. The model was successfully verified by comparing its results to an analytical solution and field data. The influence of latent heat and range of freezing zone on the distribution of temperature in the process of freezing–thawing was studied, and a numerical simulation about a tunnel in Tibet was done to discuss the effect of insulation material. From the numerical results, it was found that the temperature of lining and surrounding rock were greatly changed with building insulation material at the surface of tunnel lining. After constructing poly phenolic insulation with thickness of 6 cm, the lining and surrounding rock will not be affected by freezing–thawing damage.