Abstract:

FDS is used to build a typical two-lane highway tunnel， the fire smoke spread characteristics and temperature distribution law of the highway tunnel with altitudes of 500 m and 4 000 m are analyzed, so as to get the influence law of the environmental factors such as low pressure, low temperature and low oxygen content on the development of highway tunnel fire. The results show that the maximum temperature of fire smoke in highway tunnels in high- altitude areas is lower than that in plain areas, and its flame height is higher than that in plain areas. The maximum temperature rising rate of the vault near the fire source is obviously higher than that of the area far away from the fire source. Under the same fire heat release rate, the one- dimensional longitudinal spread of fire smoke in the tunnel in high altitude areas is greater than that in plain areas, and the boundary between the high- temperature flue gas in the upper layer and the cold air in the lower layer of the tunnel near the fire source is more obvious, while the smoke sinking phenomenon is more obvious away from the fire source. 

Key words: tunnel fire, high altitude, smoke spread, temperature distribution, numerical simulation