The multi-factor influence of frost resistance and prevention effect of tunnel thermal insulation layer in cold areas

Abstract

To figure out the thermal insulation effect of tunnel thermal insulation layer under the action of different factors in cold areas, the heat transfer analysis module in ABAQUS software was used for the Jiangluling Tunnel to numerically simulate the temperature change of the lining. The said thermal insulation effect under different insulation layer laying methods, insulation material heat conductivity coefficients, insulation layer thickness values, and air temperature conditions was analyzed based on the range of Heat Regulation Circle (HRC), and the empirical equation proposed by Japanese Scholar Kurokawa Yoshinori was employed to calculate the laying length of thermal insulation layer, which was then verified by the safety coefficient of tunnel lining structure. The research results showed that, after the thermal insulation layer had been set, the radial depth of annulus of HRC decreased significantly, indicating that the convective heat transfer of cold air had been suppressed; from high to low, the thermal insulation performance of thermal insulation layer installed by different laying methods was: double-layer style, wall-attaching style, composite filler style, and wall-detaching style. When installing thermal insulation layer for the Jiangluling Tunnel, the wall-attaching style thermal insulation layer is suggested; the thickness of thermal insulation layer should not be less than 5.5 cm; the thermal insulation material should take a thermal conductivity coefficient between 0.025 and 0.04 (W/m.k) and be laid throughout the entire tunnel; when the temperature drops below −17 °C, extra thermal insulation measures should be taken to ensure the frost resistance and prevention ability of the tunnel structure.

Keywords

• Lining structure
• Thermal insulation layer
• Heat Regulation Circle (HRC)
• Frost resistance and prevention