Abstract:

In the construction of tunnels with high geotherm in tropical areas, ice cubes are often used as an auxiliary means of cooling as they are economic and readily accessible. In order to rationally select the quantity and layout parameters of ice cooling, the software Fluent is used to simulate the temperature field variation of Wuzhishan extralong highway tunnel in Hainan under conditions of ventilation and ice cooling, and the influence of two factors of ice quantity and the layout position on the longitudinal and face temperature fields are analyzed. Some conclusions are drawn as follows: (1) The temperature drop is more obvious within 5 m ahead of and behind the ice cube layout position, and the temperature drop range gradually expands over time. (2) When 1.5 m3 ice cubes are arranged on both sides of face, the lowest temperature within 5 m of the tunnel face is 18 ℃, which is about 10 ℃ lower than face without ice cube; the temperature at a further distance is about 23 ℃, which is about 5~8 ℃ lower than face without ice cube. (3) Compared with the working condition of ventilation, 1 m3 of ice cubes (0.5 m3 on both face sides) can reduce the temperature of the face by about 6 ℃, and on this basis, every additional of 1 m3 of ice cubes can reduce the temperature by about 3 ℃. (4) Under same ice quantity, the scheme of arranging the ice on the axis of the air duct  outlet can reduce the temperature of the tunnel face by 3~5 ℃ more than that arranging the ice on face sides, of which the continuous cooling effect is much stronger.

Key words: highway tunnel, ice cooling, ice quantity, ice position, numerical simulation, tropical area