Research On Application Of Smoke Control In Subway Tunnel With Cross Passage

With the rapid development of global economy,the urban infrastructure was becoming perfect from people's daily needs.Because of its convenience,cleanness,punctuality,large passenger capacity and other advantages,subway has become one of the most important urban transportation modes.Because of subway tunnel's structural characteristics,once there is a fire in the subway tunnel,it will cause a huge threat to the safety of people's lives and public property.The subway fan is set in the subway tunnel,which provides fresh air for the subway tunnel,exhausts the waste gas and heat of the subway tunnel,and the research on the reasonable air flow and smoke control technology by using the subway fan has become the hot spot of the subway tunnel fire safety research.In this paper,the theoretical analysis and scale model experiment are used to study the subway tunnel with cross passage.The fire experiments of different fire sources are carried out on the subway tunnel model with one connecting passage and two connecting passages respectively.The main research contents are as follows:(1)According to the similarity theory,from the differential control equation of tunnel fire smoke flow,the Freud fire model needed for model test is established.Combined with the structure and ventilation and smoke exhaust requirements of similar rectangular tunnel,a 1:3 scale test platform with three transverse channels is established,and the compartment is set in the tunnel to cause blocking effect,the experiment is more suitable for the actual situation of fire,which shows the validity and rationality of the model experiment.(2)In this paper,the typical smoke control projects at home and abroad are listed,and the smoke control methods used are analyzed.Through theoretical analysis,the necessary smoke control conditions are defined,so as to design the smoke control experiment of metro tunnel with connecting passage.According to the fire experiment of the solid scale model,when the fire occurs in the single port,the longitudinal ventilation of the accident tunnel is adopted,and the positive pressure ventilation of the non accident tunnel is adopted.At this time,the longitudinal ventilation wind speed of the accident tunnel should be greater than 1.6m/s(converted to full scale 2.6m/s)The critical smoke prevention wind speed at the junction of the connecting passage shall be greater than 1.8m/s(converted to full scale 3.2m/s)To meet the requirements of smoke control When the fire occurs at the upstream connecting passage under the condition of two ports,the longitudinal ventilation of the accident tunnel shall be adopted,and the positive pressure air supply of the non accident tunnel shall be adopted.At this time,the longitudinal ventilation wind speed of theaccident tunnel shall be greater than 1.6m/s(converted to full scale 2.6m/s)The critical smoke prevention wind speed at the junction of the connecting passage shall be greater than2.4m/s(converted to full scale 4.1m/s)Can meet the requirements of smoke control.The staggered air supply mode of non accident tunnel has limitations in smoke prevention,which can not guarantee the fire safety of non accident tunnel and connecting passage,and can not be used in practical application(3)In the design of smoke control and exhaust of metro tunnel with connecting passage,the possible resistance loss caused by connecting passage should be considered.In this paper,the resistance coefficient of connecting passage of metro tunnel is determined through theoretical analysis and experimental measurement,and the theoretical exhaust air volume and exhaust resistance calculation formula are obtained through air network calculation method,which provides reference for the selection of fans in metro tunnel.