Study On Smoke Extraction Mode And Evacuation Of Ping An Railway Rescue Station

With the great development of China, the long railway tunnel gradually increased in number and size.’Code for Design on Evacuation Engineering for Disaster Prevention and Rescue of Railway Tunnel’had made a detailed requirement that tunnel or tunnel group which is longer than 20km should be set up emergency stations. And, emergency stations distance between should not exceed 20km. Emergency stations should have ability that people can quickly evacuate to a safe area and help themselves or rescue workers help them get outside of the cave.In this paper, the engineering background is Ping’an tunnel proposed in Chengdu to Lanzhou railway. Use the numerical simulation software-FDS to study three kinds of smoke exhaust mode what include of longitudinal smoke exhaust mode, semi-transverse arch smoke exhaust mode and semi-transverse arch side smoke exhaust mode when the rescue station was under fire. And find out which mode is the best choice. This dissertation will consider the impact on the evacuation in rescue station which under different evacuation platform width, cross channel spacing by using the three-dimensional numerical simulation software-FDS+Evac. It is concluded that the available safe evacuation time, In the end, proposed the rescue station of Ping’an tunnel optimal fire smoke extraction mode and key factor in the devise of rescue station.The following conclusions:(1) Under longitudinal smoke extraction mode, the radius of 25 m centered on fire the highest temperature was 160 ℃ and visibility was less than 10m.It was adversed effects on the evacuation, even threatened to personnel safety. If we open fan which was in the fire tunnel may cause dangerous distance increase.(2) Semi-transverse arch side smoke extraction mode could partly control the flow of flue gas and the longest spread distance was 400m. It is sufficient to achieve the separation of person and smoke. The rescue station temperature controlled below 60 ℃. When the fire broke out in the middle of the rescue station, visibility has remained at more than 15 m. When the fire broke out in the end more than 1100s, visibility was less than 10 m. When the fire broke out at the end of the rescue station is more dangerous than that occurs in the middle.(3) Semi-transverse arch smoke model was able to fully control the flue gas flow and the longest spread distance was 250m. It is sufficient to achieve the separation of person and smoke. The spreading distance of smoke is less than semi-transverse arch side smoke extraction mode. The vertical shaft type could effective use of stack effect. The temperature in the rescue station was below 53 ℃. And in the whole calculation process visibility remain above 14 m.(4) Rescue station platform width and cross channel spacing all affect the total time of evacuation. When the platform width was 0.5m, the change of horizontal channel spacing had a greater influence on the total evacuation time. When the platform width was more than 1.5 m, cross channel spacing that changes from 40 m and 60 m had no effect on the total evacuation time. When the horizontal channel spacing was fixed and the platform width was more than 1.5m, with the increase of platform width, total evacuation time almost no change. Rescue station platform width is a key parameter to determine the evacuation time.