Study On Optimization Of Smoke Control System And Evacuation Strategy Of Complex Overlapping Subway Atation Fire

In order to solve the problem of urban traffic congestion,the subway gradually begins to affect people’s lives with its huge advantages of large traffic volume,fast speed,environmental protection and so on.With the development of the subway,the fire problem has attracted more and more attention.Because the subway is located underground,relatively closed and narrow space,the occurrence of subway fire has a high risk.Therefore,the fire prevention and control work has a very important practical significance.After the fire accident,we should more effectively prevent the spread of smoke and timely exhaust smoke,and further do a good job in fire prevention.The design optimization of smoke exhaust is of great significance to provide more available evacuation time and reduce casualties.This paper takes Jiangsu Road Station of Qingdao Metro Line 4 as the research object,and optimizes the smoke control system based on the smoke flow law,and studies the evacuation strategy and influencing factors.The main research contents are as follows:(1)The smoke flow law of different fire scenes in subway station is simulated by using pyrosim software.The available evacuation time of temperature,CO concentration and visibility in the station environment reaching the risk standard is simulated and analyzed,and the fire smoke control system is optimized.(2)The optimization design of fire smoke control and extraction system is made.Firstly,increasing the mechanical smoke extraction rate can improve the smoke extraction efficiency.Compared with natural smoke extraction,double the mechanical smoke extraction rate can reduce the ambient temperature of the station from 34℃ to 20℃,reduce 14 ℃,and increase the visibility by 20 meters.The interval tunnel smoke extraction system can prevent the smoke from spreading to the station hall,and reduce the temperature by 9℃;secondly,properly increasing the height of the smoke exhaust pipe can improve the smoke extraction efficiencywhen the height of smoke outlet is 3.5m-5.5m,the temperature drop is larger;when the height of smoke outlet is 5.5m-6.5m,the temperature drop is smaller;third,when the station hall air supplement system is optimized and the fire side and non-fire side air supplement fans are turned on at the same time,the smoke exhaust effect is the best,and the temperature can be reduced by 6℃;fourth,the feasibility of canceling the rail top smoke exhaust is demonstrated,and the platform screen is proposed to be closed The smoke exhaust system on the top of the rail is cancelled while the door system is shielded,which can meet the environmental requirements of safe evacuation;(3)Using Pathfinder software,this paper studies the evacuation strategy of the station,analyzes the influencing factors of the time,simulates the comparison of the evacuation time under the normal personnel ratio and the special personnel ratio,and simulates the evacuation situation under different fire scenarios and different escalator operation conditions.The maximum passenger capacity of the station with the normal personnel ratio is 4564,compared with the number of people in condition 1 and condition2.The results show that the maximum total number of people that the station can accommodate can not exceed 2971 in the most unfavorable situation,that is,the total number must be controlled below 2971.regardless of the proportion of people,and when the number of people is less than 2122,there is no need to consider the proportion of people in the station.The proportion of personnel can meet the requirements of safe evacuation.This paper studies the smoke flow law of subway station,and puts forward the reasonable optimization design of smoke control system,which provides guidance for the safe evacuation of people in the fire condition of subway station,greatly reduces the smoke concentration and the spread rate,and provides the thinking and guidance for fire protection design and personnel evacuation strategy.