| In our country,the main evacuation method for high-rise buildings is stair evacuation.The research on stair evacuation methods can provide scientific suggestions for the planning and design of stairs in high-rise buildings,and improve the traffic capacity of building stairs and the safety of evacuation of people.Different stair evacuation methods can not only be applied to evacuating people under emergency conditions,but also can be applied to two-way flow of people on stairs under non-emergency conditions.When the density of the ascending and descending crowds in the stairs is too high,it will cause the crowds in the two directions to obstruct each other,resulting in congestion,forming a "heat-cooling" phenomenon,and increasing the probability of trampling accidents among the crowds.Therefore,it is of great practical significance to study the evacuation methods of one-way and two-way flow of stairs and pedestrians.Frist of all,in order to study the characteristics of occupants’ behavior and evacuation efficiency in the way of queuing evacuation and optional evacuation on stairs,the evacuation experiment of stairs was carried out,and the simulation was carried out by using Massmotion software.The results of the experiment show that the single person queuing for evacuation is faster,but the overall crowd density is smaller,the flow of people is smaller,the evacuation time is longer,and the queuing evacuation time is more affected by the width of the stairs.The experimental data verify the rationality of the model parameters.The simulation results show that when evacuating randomly,the change of the stair slope will affect the evacuation efficiency,and when the slope is 23°~28.5°,the evacuation efficiency reach the maximum.When queuing for evacuation,the evacuation efficiency has nothing to do with the slope of the stairs;the greater the number of occupants,the shorter the evacuation time for random evacuation compared to queuing evacuation.Secondly,based on the pedestrian parameters summarized from the previous experiments and simulation results,three different types of stairs of two-way pedestrian flow evacuation models were established,and a simulation study of the two-way flow evacuation of stairs based on Massmotion software was carried out.Choose different stair parameters and number of occupants to simulate,and compare the differences between the two evacuation methods.The simulation results show that compared with Optional evacuation,the speed of queuing evacuation is greater,the density of people is smaller,the crowding time during the evacuation process is shorter,and the evacuation efficiency is higher;as the number of occupants and the width of the stairs increase,the queuing evacuation is relatively higher The evacuation time for Optional evacuation is shorter.Finally,a one-way flow staircase evacuation simulation with different speed distributions was carried out,and five groups of people with different speed distributions were simulated with different evacuation methods.The simulation results show that whether it is queuing or optional evacuation,the more even the speed distribution of the crowd,the higher the evacuation efficiency.A simulation study of different evacuation methods was carried out for young people,old people and children under different population ratios.It was found that when the proportion of young people increased,the evacuation time decreased;The overall evacuation time is determined by the proportion and speed of low-speed people.The lower the proportion,the shorter the evacuation time,the greater the speed,and the higher the evacuation efficiency;When the number of occupants in the two flows is the same and the expected speed difference between the two flows reaches 0.4m/s,the evacuation team may experience faults,and in the same scenario,the fault time point for queuing evacuation occurs earlier than the optional evacuation.The research results can provide some certain reference for building staircase design and staircase evacuation guidance. |
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