Probabilistic risk assessment of uncertainty of fire development and evacuees in expressway tunnel

Abstract

With the development of economy, expressway tunnels have been constructed increasingly in recent years. Tunnel makes traffic more convenient, nevertheless it brings about many new fire safety problems. A probabilistic risk assessment (PRA) method for tunnel fire is proposed on consideration of uncertainty influence on fire development and Evacuees. Firstly, the initial frequencies for different fire scenarios are calculated, combined with tunnel length, traffic volume, and accident rates, ect. Secondly, using event tree analysis (ETA), probable fire scenarios are analyzed on consideration of the effect of uncertain factors in tunnel fire development, such as tunnel ventilation system, fire alarm system, and fire hydrant, ect. Finally, death risk of evacuees is calculated when untenable conditions occur. The probabilistic risk assessment method can provide a new means for quantitative analysis of fire risk of expressway tunnel. To understand the method, fire risk of the extra-long expressway tunnel, taking different fire safety designs, is analyzed in detail.