In dense crowd evacuation,especially in emergencies such as fires,the safe evacuation of large public facilities will face major challenges.At the same time,as cluster congestion tends to occur in the space where the ...In dense crowd evacuation,especially in emergencies such as fires,the safe evacuation of large public facilities will face major challenges.At the same time,as cluster congestion tends to occur in the space where the flow rate drops sharply,the superposition of fire incidents and bottleneck areas can easily evolve into malignant disasters and crowd stampedes with serious harm and influence.In this paper,Massmotion based on social force model is used to carry out a numerical simulation on exit position and corner exit form to find out the mechanism and influence law of the slight architectural adjustment on the flow at bottleneck.The results show that the traditional middle exit design is not the best,and the evacuation efficiency of the corner exit is higher than that of the middle exit.Compared with other corner exits,the average time interval between two adjacent persons passing through the bottleneck under the 30°corner exit is the shortest,and the probability of outlet clogging drops the fastest,exceeding 18%of the slowest descending speed.At the 0°corner exit,the waiting time cost of pedestrians is high and the risk of evacuation is high.The outcomes of this work can provide reference for the structural design of the building and the safe evacuation of personnel,so as to improve the evacuation efficiency and safety of pedestrians in the building to some extent.展开更多
Building exit has always been an emphasis of research in the field of evacuation.Existing studies on crowd flow characteristics at building evacuation bottlenecks usually focus on plane exit,but insufficient attention...Building exit has always been an emphasis of research in the field of evacuation.Existing studies on crowd flow characteristics at building evacuation bottlenecks usually focus on plane exit,but insufficient attention has been paid to the characteristics of crowd flow at the convex exit.Convex exit can be considered as such a structure like a double-bottleneck linked passage.This paper aims to study the influence of geometric structure characteristics of the convex exit on crowd evacuation and put forward the optimal design strategy of this structure,so as to improve the efficiency of evacuation in an emergency.Using social force model-based software,MassMotion,it is found that convex exit is indeed more efficient and safer than common plane exit in terms of evacuation time and pedestrians'congestion,especially when the desired speed is relatively higher,indicating that convex exits are more suitable for crowd evacuation in case of emergency.Four size-related parameters of convex exit are analyzed in detail,namely the width of the bottleneck at passage(W_(p)),the passage width(W),the passage length(L),and the exit width(W_(e)),to find out the optimum design of convex exit.The research shows that the optimal size ratio is that Wp:W:L:We equals 1.5:1.75:3.5:1,and as the overall magnification of building size and the number of pedestrians increases,the evacuation time gradually tends to a stable value,which indicates that this optimal ratio has good adaptability in size effect.Finally,based on the in-depth mechanism of pedestrian flow at the convex exit,three possible application scenarios are proposed to illustrate the feasible optimum design of the convex exit.The results of this study can provide new ideas for research on the structure of building exits.展开更多
基金This research was sponsored by the National Natural Science Foundation of China(No.71774079)the Major Natural Science Research Projects in Colleges and Universities of Jiangsu Province(No.19KJA460011)+2 种基金the National Natural Science Foundation of China(No.51874182)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX20_0365)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘In dense crowd evacuation,especially in emergencies such as fires,the safe evacuation of large public facilities will face major challenges.At the same time,as cluster congestion tends to occur in the space where the flow rate drops sharply,the superposition of fire incidents and bottleneck areas can easily evolve into malignant disasters and crowd stampedes with serious harm and influence.In this paper,Massmotion based on social force model is used to carry out a numerical simulation on exit position and corner exit form to find out the mechanism and influence law of the slight architectural adjustment on the flow at bottleneck.The results show that the traditional middle exit design is not the best,and the evacuation efficiency of the corner exit is higher than that of the middle exit.Compared with other corner exits,the average time interval between two adjacent persons passing through the bottleneck under the 30°corner exit is the shortest,and the probability of outlet clogging drops the fastest,exceeding 18%of the slowest descending speed.At the 0°corner exit,the waiting time cost of pedestrians is high and the risk of evacuation is high.The outcomes of this work can provide reference for the structural design of the building and the safe evacuation of personnel,so as to improve the evacuation efficiency and safety of pedestrians in the building to some extent.
基金This research was sponsored by the National Natural Science Foundation of China(No.71774079)the Major Natural Science Research Projects in Colleges and Universities of Jiangsu Province(No.19KJA460011)+2 种基金the National Natural Science Foundation of China(No.51874182)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX21_0438)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Building exit has always been an emphasis of research in the field of evacuation.Existing studies on crowd flow characteristics at building evacuation bottlenecks usually focus on plane exit,but insufficient attention has been paid to the characteristics of crowd flow at the convex exit.Convex exit can be considered as such a structure like a double-bottleneck linked passage.This paper aims to study the influence of geometric structure characteristics of the convex exit on crowd evacuation and put forward the optimal design strategy of this structure,so as to improve the efficiency of evacuation in an emergency.Using social force model-based software,MassMotion,it is found that convex exit is indeed more efficient and safer than common plane exit in terms of evacuation time and pedestrians'congestion,especially when the desired speed is relatively higher,indicating that convex exits are more suitable for crowd evacuation in case of emergency.Four size-related parameters of convex exit are analyzed in detail,namely the width of the bottleneck at passage(W_(p)),the passage width(W),the passage length(L),and the exit width(W_(e)),to find out the optimum design of convex exit.The research shows that the optimal size ratio is that Wp:W:L:We equals 1.5:1.75:3.5:1,and as the overall magnification of building size and the number of pedestrians increases,the evacuation time gradually tends to a stable value,which indicates that this optimal ratio has good adaptability in size effect.Finally,based on the in-depth mechanism of pedestrian flow at the convex exit,three possible application scenarios are proposed to illustrate the feasible optimum design of the convex exit.The results of this study can provide new ideas for research on the structure of building exits.
