Study On Safety Evacuation Of Urban Rail Transit During Fire

Due to the advantages of high efficiency, convenience and comfort, etc., Urban rail transit gets increasingly the favour of the traveler, and has become an important part of urban public transportation. In recent years, Urban rail traffic gradually adopted in tunnel when through the city, and has a very big construction demand and the broad application prospect. However, urban rail transit tunnel fires more dangerous than ordinary tunnel fire, in case of fire will cause serious casualties and economic losses. Therefore, it is extremely important and significant to research the risk and evacuation of urban rail transit tunnel fire.Based on the comprehensive analysis of the cause and characteristics of urban rail transit tunnel fire, and combined with the four kinds of accident model theory,which has a great impact on domestic, and the related standard, analyzed the hazard and the evacuation time of urban rail traffic tunnel fire of Riverside new town to the City Hall Station interval Xiangjiang River Tunnel CZT intercity railway by using event tree method, accident tree method, fire simulation software FDS and the monte carlo method respectively. The main research work and conclusions include:(1) Through analyzed the "person", "machine", "ring" three aspects of factor of urban rail transit tunnel, based on the accident model theory knowledge, established the accident cause model of urban rail transit tunnel fire. Analysis of the causes,characteristics and the harm of human body of urban rail transit tunnel fire; analyzed the risk factors of fire different stages by event tree and fault tree.(2) By comparative analysis of the advantages and disadvantages of three types of common tunnel evacuation, concluded that double holes each other service tunnel model are the most widely used and economy. In the basis of the relevant provisions,analyzed the two evacuation model of urban rail transit tunnel, and the route chart of two different evacuation mode in the five different circumstance were drawn. Finally,it is concluded that when the train lost power after the fire, stopped at a cross-channel nearby, and the cross-channel blockage situation, evacuation is the most unfavorable position. conditions of ensure safe evacuation is: ASET ?RSET.(3) Combined with the specific situation of the engineering example, using the fire simulation software FDS simulated urban rail transit tunnel fires; when the maximum heat release rate is 15 MW, the fire growing type is t2 fire type, growth factor is the rapid growth, the four different working conditions’ gas distribution,temperature distribution, visibility and CO concentration distribution is analyzed. It is concluded that when the wind speed is 3 m/s, has obvious inhibition to the smoke reflux, and the critical wind speed is 3m. the available safe evacuation time(ASET) of Z1 Z2 Z3 and Z4 is : 430 s, 462 s, 527 s and 516 s respectively.(4)Combined with the engineering example, based on the Monte Carlo method to obtain the personnel required safe egress time samples, and through compare available safe evacuation time(ASET) with the required safe evacuation time(RSET),calculated the deaths probability of different risk area, concluded that system is safety but still can take some measures to improve its safety.