Abstract:  Ventilation shafts are often required to solve the construction ventilation problems in extralong tunnels or multiple working faces in tunnels with a single slope. To investigate the factors affecting the ventilation of the shafts, the vertical tube is used to replace the shaft, it is assumed that the temperature of the wall changes linearly along the shaft, and the expression of the average wind speed of the steadystate airflow in the shaft section with heat source is derived subsequently. Then, the expression of demanded ventilation volume for shafts is obtained using Taylor series. The results reveal the following: (1) When the atmospheric pressure 〖WT５《TNR#I》〗P〖WT５《TNR》〗a5 at the tunnel entrance is consistent with the change of the atmospheric pressure 〖WT５《TNR#I》〗P〖WT５《TNR》〗a1 at the shaft orifice, the difference between the two will not affect the construction ventilation of tunnel. (2) When the changes of 〖WT５《TNR#I》〗P〖WT５《TNR》〗a5 and 〖WT５《TNR#I》〗P〖WT５《TNR》〗a1 are not synchronous, the increase of the difference (〖WT５《TNR#I》〗P〖WT５《TNR》〗a5-〖WT５《TNR#I》〗P〖WT５《TNR》〗a1) will result in the decrease of the inlet air volume of the shaft. (3) The wind pressure required by the fan located at the bottom of the shaft decreases with an increase in atmospheric temperature at the orifice, and increases with an increase in the stratigraphic temperature. (4) When the environmental parameters and working conditions are specified, the shaft ventilation rate expression can be used for quantitative analysis, which is conducive to fan selection and intelligent control of fan operation.

Key words:  , tunnels, ventilation shaft, ventilation volume, influencing factors, fan pressure