Cellular Automata Simulation On Special Human Behavior Of Occupant Evacuation In Emergency

Research work on occupant evacuation is mainly developed by computer simulation because of the absence of real data and theveracity of experiments. Some researchers are now trying to do some research on special psychology and behavior in evacuation, but questionnaire after disaster is still the main method.Our two dimensional cellular automata occupant evacuation random model which is based upon the existing cellular automata models and "social force" model is essentially a discrete social force model.Firstly, some useful knowledge of cellular automata and evacuation model are introduced briefly. Then, occupant evacuation in fire room is simulated and the influence of visual field on evacuation behavior is emphasized. Occupants' evacuation routes are changed by adjusting the value of danger grade; the change of visibility caused by smoke is depicted by the radius of cell's neighborhood.Secondly, some special psychology and behavior in emergent evacuation are simulated including the psychology of going with the crowd, sub-group phenomenon and the kin behavior. Some interesting phenomena, such as jamming, incoherence, gathering, backtracking and waiting, are caused by sub-group behavior; the disadvantages of sub-group and kin behavior are analyzed; the psychology of going with the crowd is not always harmful. The proper psychology can transfer the information effectively, while the severe psychology will reduce the using efficiency of exits, cause passive route choices and result in jamming. Moreover, the psychology of going with the crowd (GWC) in evacuation is classified as directional GWC and spacial GWC, and quantitative analysis on the influence of these two kinds of psychology on evacuation under different physical conditions are discussed.Finally, the influence of building exit structure on occupant evacuation behavior is investigated theoretically. In this part, exit dynamics of occupant evacuation in an emergency is analyzed first. The "arch" shape of occupant distribution at building exit caused by dense pedestrian flow is vividly observed by simulation demo; the relations between total flux and exit width are fitted into a three order polynomial equation; the symmetrical layout of building exits is also discussed. Then, pedestrian flow of evacuation is regarded as a kind of conscious granular flow, the dimensionless critical value of exit width corresponding to dense-to-dilute flow transition is discussed, and the infection of exit separation on evacuation behavior is analyzed.