Study on influence of breathing zone combined with underfloor makeup air supplement on smoke exhaust of road tunnel fire

In the era of rapid economic development, tunnel construction projects are increasing year by year in China, continuously expanding the urban network In the era of rapid economic development, tunnel construction projects are increasing year by year in China, continuously expanding the urban network radiation area, and accelerating the progress of the national modernization project. The subsequent tunnel traffic fire accidents are also increasing When a tunnel fire occurs, how to effectively supply makeup air to prevent the fire smoke from spreading to the evacuation passage of the When a tunnel fire occurs, how to effectively supply makeup air to prevent the fire smoke from spreading to the evacuation passage of the tunnel and exhaust the smoke as soon as possible has become a key concern in the field of tunnel disaster prevention. The layout of the smoke exhaust outlets under the mode of breathing zone combined with underfloor makeup air supplement was mainly used to study the problem of smoke exhaust in tunnel fires. The results show that under the same smoke exhaust flow rate, with the increase in the area of the results show that under the same smoke exhaust flow rate, with the increase in the area of the smoke outlet, the smoke exhaust efficiency of each exhaust outlet increases, and the total efficiency also increases. The width of the exhaust outlet has a significant effect on the smoke exhaust efficiency. However, the length of the exhaust vent has little effect on the efficiency of smoke exhaust. Under the mode of breathing zone combined with underfloor makeup air supplement, arranging smoke outlet with a size of 2 m×1.5 m every 10 m has a better smoke extraction effect, and the total smoke exhaust efficiency can reach 75.77%. Fire safety of road tunnels has always been the focus of social concern. The makeup air supplement and smoke exhaust mode proposed in this study is expected the makeup air supplement and smoke exhaust mode proposed in this study is expected to provide a theoretical basis for the design of tunnel smoke prevention and exhaust systems