Abstract:

The rational prediction of the air temperature in a running tunnel can help improving the tunnel environment. An axisymmetric twodimensional heat conduction model of the surrounding rock combining radial and axial heat flow is derived and an air/surrounding rock heat exchange model is given. And then the two models are coupled by introducing the thirdtype boundary conditions. The analytical solutions of the surrounding rock temperature and air temperature in tunnels are further deduced. The temperature difference in the roadway calculated by the analytical solution and the numerical solution reported in the literature is within 0.5 ℃. The Wuhan Yangtze River Tunnel is taken as an example to calculate and analyze the air temperature in the tunnel. The results show that: (1) The difference between the calculation results of the temperature in the tunnel and the measured data is mostly within 1 ℃, and the temperature variation trend is consistent, which verifies the correctness of the analytical solution recommended. (2) With the increase of the wind speed, the outlet temperature keeps decreasing and the decrease gradually decreases, i.e. the cooling effect has gradually become insignificant, which indicates that the wind speed control in the running tunnel needs to consider both the cooling effect and power consumption.

Key words: running tunnel, air temperature, steadystate heat conduction, analytical solution