Study On The Influence Of Fire Source Spacing And Power On Smoke Spread In Tunnel With Double Fire Source

In recent years,with the development of tunnel construction in China,the mileage of highway tunnel has increased significantly.The construction of highway tunnel greatly facilitates the communication between regions and makes People’s Daily travel more convenient.However,with the increase of the number of highway tunnels,various traffic accidents occur frequently.Tunnel fire is one of the most serious tunnel accidents.Because the highway tunnel is a relatively closed structure,when the fire occurs,the high-temperature smoke cannot be discharged in time,but spread along the tunnel structure inside,thus causing a serious threat to the life safety of the people inside the tunnel.Most of the previous researches on tunnel fire focus on the single fire source with single fire source in the tunnel,but there is not enough research on the fire situation with multiple fire sources in the tunnel.At the same time,in the past research process,the cross-section form of tunnel model test bench is mostly rectangular,while the crosssection of highway tunnel is usually horseshoe,and the existing research conclusion is also different from the actual tunnel fire situation.Therefore,in order to fully study the smoke spreading law of tunnel fire with double fire sources,this paper studied the influence of different fire source spacing and downstream fire source power on the smoke spreading law of tunnel fire by setting up a 1:10 horseshoe section tunnel model test platform.The research of smoke spreading law of tunnel fire is mainly divided into two aspects:temperature characteristics under the roof and smoke backflow phenomenon.In the research on the temperature characteristics of flue gas in tunnel roof,a basic model of maximum temperature and longitudinal temperature attenuation of flue gas under tunnel roof with single fire source is established in this paper,and the theoretical model is verified by corresponding model experiments.In a single fire in tunnel fire research conducted on the basis of different source spacing and the source of power for double fire in tunnel fire ceiling temperature characteristic research,the highest temperature by equivalent method of double fire in tunnel fire ceiling will be the study of the development of the highest temperature of flue gas,flue gas temperature and establish the ceiling longitudinal distribution of the basic model.In the research on the phenomenon of tunnel fire smoke flow,this paper has carried out groups of single fire in tunnel fire model experiment on the basis of the existing flue gas flow length model is verified,and carried out under the influence of different source spacing and fire power,double fire in tunnel fire experiment,reveals the proportion of different distance between fire source and the source of power for the influence of double fire in tunnel fire smoke flow length.Considering the fitting relationship between the correlation coefficient of the theoretical model of fire smoke backlayering length and the distance with fire power ratio of fire sources,the basic model of fire smoke backlayering length of tunnel fire with double fire sources is established.