Research Into Optimizing Setting Up Of The Split-Flow Wall Based On Safety Evacuation

Along with progress of social economy of our country and development of the science and technology in building industry, building structure increasingly trend to intelligent and complication. Reasonable construction structure, which has become an important index in risk assessment of large-scale social events, can ensure safety evacuation. Evacuation ability of building depends on the exit. Proper exit design can improve the efficiency and safety of evacuation. The split-flow wall before exit can not only improve the evacuation efficiency by increasing pedestrian flow rate at exit, but also can enhance the security of evacuation by reducing the crowd degree before exit.In the present paper, based on cellular automation, a floor field model has been established. Considering the distance to the exit and the crowd distribution before exit, we put forward a reasonable exit-selection model. The conflict function has been introduced to solve the problem of conflict between the evacuees. Flow rate and conflict numbers are assigned as two key parameters to analyze the influence of split-flow wall on evacuation efficiency and safety. Through a lot of simulation experiments, we obtained general design rules of the split-flow wall:(1) when split-flow wall exists, there is a critical value of exit width;(2) when faced with conflicts, if the evacuees show heavy competition behavior, the highest evacuation efficiency arises in the case that the distance between split-flow wall and exit is three persons; on the contrary, if they show light competition behavior, the most efficiency distance is one person;(3) when the length of the split-flow wall is set as a half of evacuation space width, conflict times in evacuation process is the least, which is the safest case for evacuation. The best length of split-flow wall doesn’t in relation to degree of competition. When crowd density greater than0.1, the effect of split-wall is more obvious.Through the numerical simulations, we master the efficiency of split-flow wall in an emergency situation, and get the basic rules for setting up. The design of split-flow wall can not only provides the reference for designers and architects in the design of physical Settings, but also can alleviate the dense regions of the crowd congestion, and reduce the probability of accident.