Experimental verification of escape efficiency enhancement by the presence of obstacles

Abstract

In emergency evacuation situations, placing an obstacle may be seen intuitively as a worse condition which may result in a slower evacuation time. Nevertheless, it is possible to lower the internal pressure in front of the exit and as a result preventing from clogging. This phenomenon has mainly been studied by numerical simulation, and so far the real-life human evacuation experiments considering different size, shape and placement of obstacles are rarely reported. In this paper, to verify the escape efficiency enhancement by the presence of obstacles and refine the experimental design, the simulation efforts are firstly carried out using the social force model. Then a series of real-life human evacuation experiments considering different types of obstacles are performed with the geometrical layouts suggested by social force model. It is observed the evacuation efficiency of pedestrians is actually quite sensitive to the geometrical parameters of obstacles, and the average evacuation time in human experiments can be reduced by suitable layout of obstacles. Compared to single-pillar obstacle, the panel and double-pillars obstacles are more robust and stable which could better improve the evacuation efficiency of pedestrians. Finally, to reveal the underlying mechanism of evacuation performance enhancement, the density profiles of pedestrians are compared based on the trajectories and Voronoi method. It is demonstrated that the essential physical mechanism behind the evacuation efficiency enhancement while placing an obstacle actually is a significant decrease of the density level in crowded region by effective separation in space.