Abstract:

Radial propagation of temperature field of surrounding rocks of tunnel in cold regions is the key to design of thermal insulation. The study of temperature field of surrounding rocks of tunnel in cold regions focuses on site monitoring and theoretical analysis. Full scale testing device for temperature simulation is developed, on basis of which simulation tests with and without thermal insulation layer are carried out; and the radial propagation laws of temperature of surrounding rocks and support structure of tunnel in cold regions are analyzed. The study results show that: 1) The temperature of contact face between primary shotcrete and surrounding rocks is 0 ℃ after 90 h under the conditions of environmental temperature of -9℃ and no thermal insulation layer; and the surrounding rocks froze when the temperature keeps going down. The temperatures of every interface of structure become stable after 192 h and under condition of stable environment temperature of -12.5 ℃. 2) The internal temperatures of support structure and concrete are larger than 0 ℃ after 450 h under the conditions of environmental temperature of -12.5 ℃ and thermal insulation layer of 4.5 cm thickness. 3) The thermal conductivity and the thermal diffusivity of the thermal insulation layer, support concrete and surrounding rocks of the tunnel are determined. The results can provide reference for thermal insulation design of tunnels in cold region.

Key words: tunnel in cold region, radial temperature field, thermal insulation layer, propagation law, model test