Research on Fire Smoke Control of an Ultra-wide Road Tunnel with Lateral Exhaust

The existence of the ultra-wide road tunnels improves the transportation efficiency and promotes economic development. However, fire hazards cannot be ignored. Thus, a single entrance 4-lane road tunnel is selected to explore the fire smoke control effect of an ultra-wide road tunnel with lateral exhaust. First, a scale model experiment is utilized to verify the accuracy of the numerical model and then in the influence of the most unfavorable position of the fire source, the number of open smoke outlets and the amount of smoke exhaust volumes on the smoke control effect of tunnel fire under the lateral exhaust mode is simulated by a three-dimensional model. The results show that the distribution pattern of fire smoke in an ultra-wide road tunnel under the lateral exhaust mode is affected by the lateral position of the fire source. When the fire source is closer to the sidewall of the exhaust duct, the smoke distribution that is inclined to the sidewall of the tunnel is more obvious. Based on the comparison among the time of the smoke spreading to the tunnel entrance, the spreading distance of 60 °C smoke, and the smoke exhaust efficiency under various working conditions, it is concluded that the most unfavorable lateral fire source location is in the middle of the tunnel. What’s more, 4 open smoke exhaust ports with 200 m3/s exhaust volume near the fire source can achieve the best smoke control effect.