Study On The Fire Spread And Evacuation Of Road Tunnel-based On The Safety Of Transportation Vehicle Personnel

With the continuous improvement of the transportation system,road transport has made a great contribution to economic and social development because of its mobility and adaptability.However,the transportation safety problem has been outstanding in current condition,various accidents have raised higher demand for the stable and coordinated development of road transportation.As one of the accidents,tunnel fire has been widely concerned because of its large-scale impact and serious consequences.Current study on tunnel fire accidents are mainly concentrated on tunnel ventilation,spraying device and tunnel fire smoke,temperature,CO,visibility and so on,many studies choose constant power in order to simplify the calculation of the heat release rate,although the calculation is simplified,it cannot simulate tunnel fire growth and decay.The study on the passenger evacuation is based on the theory to calculate the time of escape and compared with the time of the available safety egress time.However,under the fire circumstance,the individuals show different reaction characteristics,so it is a huge and complicated job to study the evacuation of trapped personnel comprehensively and accurately.Based on the Pyrosim simulation software,this study establishes the tunnel model based on the actual tunnel size,and selects the thermal release rate value,by setting different ventilation speed and whether there are vehicles in the tunnel to simulate the traffic congestion,the transmission law of smoke,temperature,CO and visibility are analyzed according to the simulation results,and guide the trapped personnel to choose the safe escape route.In the aspect of evacuation research,by importing the generated fire scene into Pathfinder,the escape route,speed and congestion condition of the personnel are observed in the case of constant change of fire scene.According to the fire development and evacuation result,determine whether the tunnel safety facilities can meet the evacuation needs.Simulation proves that the mechanical ventilation in the tunnel has a great influence on the smoke,temperature,CO and visibility in the tunnel.When the speed of ventilation reaches a certain value,the flue gas flow can be completely inhibited.In the tunnel,smoke,visibility and temperature are the main factors that affect the driver's evacuation.The concentration of CO is always within the acceptable range of the passenger in the evacuation path.In the tunnel,smoke subsidence is down along the two sides of the tunnel,and the temperature has minor difference on both sides of the tunnel,the concentration of CO on both sides of the tunnel is relatively high.So the personnel should try to evacuate in a lower position in themiddle of the tunnel.Based on the study of tunnel fire and evacuation,analyzes the evacuation rule under typical working conditions and estimates casualties,so as to provide theoretical assistance for tunnel construction,safe operation and road transport safety guidance and education department.