Study On Smoke Control And Personnel Evacuation Of Fire In Subway Tunnel

With the development of the rail transportation in recent years,underground rail transportation is developing rapidly.In many cities there are formed underground transportation network and subway becomes the first transportation way of travel because of greatly facilitate people’s travel,saves the waiting time,safe and reliable.But subway fire becomes the main factors of the personal property safety to threat the passengers.Fire is easily to cause group die and group injury due to the small space of make the fire spread fast,more exhaust gas generation,hard smoke removal,rising fast temperature,difficulty to detect the characteristics of fire and fire extinguishing so that passenger’s life and property security caused great harm.In order to effectively solve the subway tunnel fire occurs,personnel escape distance is longer,the greater danger’s problem.If a cross-passage exists,it may be helpful for passengers to escape.According to the location of fire relative to train and the location of train relative to tunnel,there are many kinds of possible situations.Among them,there are two situations most dangerous.One is that the fire is in the middle of train and the train is near the middle of the tunnel.The other is that the fire in the middle of the train and the train is just the middle of the tunnel.This paper mainly completes the following studies:Taking the subway tunnel as the research object,given the personnel characteristics of metro peak distribution ratio based on municipal national census population and the distribution of rush hour.First,the accuracy of software simulation is verified when contrast the empirical formula and Pathfinder software simulation results.Second,personnel evacuation when the train is near the middle of the tunnel was studied without considering the personnel under the influence of the vertical and horizontal to smoke.The results show that adopting conventional cross-passage can’t assure the passengers safety evacuation.The available safety egress time is less than required safety egress time when the distance of train near cross-passage distance is greater than 150 meters.The required safety egress time was decreased by increasing the cross-passage width or quantity.So the passengers can escape safely.Based on the above research,the tunnel cross-passage improvement project can be better applied in the process of metro design,but have completed construction of subway tunnel engineering,it takes lot’s of manpower and reasonable way of ventilation.Smoke exhaust can ensure the safety of personnel evacuation.Based on the FDS fire simulation software,reasonable ventilation mode is analyzed and compared with the traditional push-pull ventilation.The results show that passengers cannot escape safely if there is not a cross-passage available,because the fire smoke soon reaches the level of danger to human body.If there is a cross-passage for escaping or discharging smoke,the smoke flow can be controlled,and the time of risk to the human body can be delayed.So the passengers can escape safely.Semi-transverse ventilation system is studied in the smoke spread of situation when the train is near the middle of the tunnel.Through comparing four conditions,it is concluded that open two smoke vent near fire,smoke can be controlled between two exhaust vent in the event of fire and person can achieve safety evacuation conditions that needn’t longitudinal ventilation.