Study on Fire Smoke Characteristics and Ventilation Mode of Extra-long Highway Tunnel Group
In order to solve the problem of ventilation and smoke exhaust in extra-long tunnels,a three-dimensional numerical model of fire scene in extra-long tunnels was established by FDS software through the calculation of tunnel air demand.The smoke movement law of full longitudinal smoke exhaust and segmented smoke exhaust in extra-long tunnels was analyzed,and a segmented smoke exhaust scheme of full longitudinal jet fan+auxiliary smoke exhaust channel was proposed for the Beizhongshan No.1 and No.2 tunnels.Then,the scheme of segmented smoke exhaust in the Beizhongshan No.1 and No.2 tunnels is compared.Finally,an optimal scheme is obtained through structural form,fan configuration,construction difficulty,project cost and other factors.The results show that:1)The segmented smoke exhaust method can effctively control the fire smoke downstream of the fire source and ensure the evacuation safety upstream of the tunnel.2)The main factors affecting the longitudinal ventilation of the tunnel are the longitudinal slope and length of the tunnel.For the downhill tunnel,the ventilation condition plays a major control role.For the uphill tunnel,the operating condition of 80 km perhour plays a major control role.After comparison and analysis.3)Considering multi factors,a better ventilation scheme is obtained.Beizhongshan No.1 tunnel adopts the scheme of full longitudinal+horizontal guide+ground fan room,and Beizhongshan No.2 tunnel adopts the scheme of full longitudinal+shaft+underground fan room.The research conclusions can provide reference for similar projects.
long tunnel grouptunnel ventilationfire numerical simulationsectional smoke exhaustscheme comparison and selection
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