Simulation of Evacuation in a Twin Bore Tunnel: Analysis of Evacuation Time and Egress Selection

In this paper, an experiment performed in a twin bore tunnel is simulated with Pathfinder and FDS+EVAC. The non-intervened case and the intervened case are constructed to analyse the difference between experiment and simulation with Pathfinder. Data obtained indicate that simulation results match the experiment well. Main reasons that cause difference may be their panic, fear, time loss in information processing, unwillingness to abandon properties, and social influence (maybe the most important one). Egress selection plays an important role in influencing evacuation time, but it is impossible for all occupants to select their nearest exits for evacuation in the real circumstances influenced by other factors. After comparing evacuation time in cases of Pathfinder (intervened case) without considering delay time in advance, Pathfinder considering delay time in advance, and FDS+EVAC (including detection time and reaction time), we can conclude that the case with FDS+EVAC is better than the one with Pathfinder without considering delay time in advance, and the case with Pathfinder considering delay time in advance is better than the one with FDS+EVAC. Reasonable suggestions for a Pathfinder simulation case are changing egress selection if necessary, and taking into account delay time when the occupants don’t start to evacuate at the same time.