Experimental And Numerical Studies On Evacuation On Stairs Based On Agent Model

The stairs are the main and even the only evacuation route in the building,when fire occurs.Thus,efficient evacuation of the staircase is the important security for personnel safety in emergency.As a vertical evacuation,staircase evacuation has its particularity,different from horizontal evacuation.Therefore,to study the characteristics of the evacuation behavior and the law of movement of the personnel in the staircase is significant to reducing the casualties and ensuring the public safety and optimizing the architectural design.Firstly,this paper conducted observational experiments to observe the typical characteristics of staircase evacuation,and analyzed the formation principle and possible hazards.A control body model of staircase was established to describe the merging flow accumulation effect mathematically.Evacuation management measures were proposed,such as directing and guiding personnel,controlling the time for people on different floors to enter the stairs,setting up special waiting areas for handicapped people,and adding handrails.Under normal conditions,the evacuation speed of the staircase area is normally distributed,the maximum speed is 1.07m/s,the minimum speed is 0.32m/s,and the average value is 0.63m/s ± 0.01m/s.Most of them are concentrated in the range of 0.5m/s-0.8m/s.Secondly,multi-story staircase evacuation experiments and merging flow characteristics experiments were conducted.The multi-story staircase evacuation experiment took 77 s,and the speed of participant walking through two adjacent floors was in the range of 0.55-1.37m/s,and there were the phenomena of S2-1>S4-3>S3-2.The reverse trend of density and flow with time was observed.The merging flow characteristics experiment took 96 s and the velocities distribute in the range of 0.7-0.9m/s,which was lower than that of multi-story staircase evacuation experiments,indicating that merging flow caused the decrease of average velocity.When merging flow occurs,evacuees on the floor will enter or accelerate into the stair section first,and evacuees from the previous floor will be forced to slow down or even wait in line.Density and flow show phase changes over time in the merging flow characteristics experiment.Then,using the experimental data combined with the theory of agent and the theory of evacuation dynamics,the evacuation model of stairs based on agents is constructed.A boundary layer is introduced to process the entity,and a method for exporting the staircase area is proposed.A dynamic model considering the extrusion and friction between the agent and the entity is established,and an agent perception,response,vision,and velocity model are established.Ensure no overlap,space division and smooth processing and other optimization measures were proposed.Finally,related software was developed using C++,and the software was used to simulate the two evacuation experiments.The simulation reproduces the phenomena in the experiment.The simulation results are in agreement with the experimental values.