Abstract: The smoke spreading distance, visibility at 2 m height and smoke exhaust efficiency of the system are taken as the key criteria to determine the reasonable cross-section air supply area. FDS is used to simulate the fire scene of oil tank truck in 1%, 3%, 5% and 7% slope tunnels. The results show that: When the slope is less than 5%, the proportion of cross-section air supply area increases with the increase of slope; When the slope is more than 5%, the proportion of cross-section air supply area remains at 80%. According to the numerical relationship between the proportion of cross-section air supply area and tunnel slope, the model of non-dimensional cross-section air supply area slope correction coefficient is proposed.

Key words: slope tunnel, central smoke extraction, longitudinal air supply, cross-section air supply area