Study On Evacuation Optimization Of Large Public Buildings Based On Accident Causation Theory

As an important place for personnel gathering and distributing,the safety evacuation of personnel is particularly important in the operation of large public buildings.Once an accident occurs in a large public building,it will cause huge casualties.How to evacuate a large number of people from inside the building to a safe area in a short time becomes a very urgent and critical topic.Through investigation,it is found that although accidents in large public buildings are rare,casualties are extremely serious after accidents due to complex evacuation routes,congestion of evacuation channels,crowding and trampling of people,etc.Therefore,it is necessary to conduct evacuation optimization research for large public buildings.Based on the behavioral safety"2-4"model theory,this paper analyzes the large-scale public construction accidents from the direct causes,indirect causes,root causes and root causes.The causative factors were numbered,the action paths among all factors were drawn,and the evacuation safety causative network of large public buildings was formed.The importance of nodes（causative factors）in the network was evaluated,and the key causative chains affecting evacuation of large public buildings were obtained.According to the analysis results,the evacuation design of a large public building was optimized,the effectiveness of the evacuation design was verified by simulation,and the evacuation optimization countermeasures were proposed.The specific conclusions are as follows:（1）Using the"24Model"to analyze 25 accidents of large public buildings,the results show that there are 4 types of unsafe actions and 3 types of unsafe physical conditions that cause accidents;The lack of safety ability of personnel is the cause of the occurrence of unsafe actions and unsafe physical state,which mainly falls into four categories.The lack of safety management system is the root cause of the above safety ability and unsafe action,unsafe physical state,there are mainly three categories;Finally,it is concluded that there are 16 major deficiencies in the safety culture of the 25 accidents.（2）The causes in the accident analysis are taken as nodes in the network,that is,unsafe physical state,unsafe action,safety capability,safety management system and safety culture are taken as nodes in the network,and the causal chain relationship among all factors is taken as directed edges.Gephi is used to draw the evacuation safety cause network,which has a total of 41 nodes and 112 directed edges.The importance of network evacuation safety was evaluated comprehensively.The results showed that the importance of unsafe state was ranked as B₃（0.616）,B₂（0.589）,B₁（0.567）in descending order.The importance of unsafe actions in descending order was A₄（0.585）,A₂（0.560）,A₁（0.538）,A₃（0.501）;The importance of security capability in descending order was:C₄₂（0.643）,C₄₃（0.641）,C₃₁（0.624）,C₄₁（0.598）;The importance of safety management system in descending order is D₃₄（0.952）,D₃₅（0.842）,D₃₂（0.746）,D₃₃（0.690）,D₃₁（0.072）.（3）On the basis of importance assessment and combined with the interaction between various contributing factors,two key cause chains affecting evacuation of large public buildings are analyzed:D₃₄→C₄₂,C₄₃,C₁₃,C₂₂→B₁,B₂,A₁,A₂→evacuation design and structure.D₃₅→C₁,C₂,C₄→B₂,B₃,A₄→human behavior.（4）Carry out evacuation optimization design and simulation verification of a large public building according to the key cause chain affecting evacuation safety.By comparing the congestion situation,evacuation efficiency and total evacuation time of each safety exit before and after optimization,it is found that the evacuation time after optimization is about 60s faster than that before optimization,and the congestion situation of each safety exit is significantly improved after optimization,and the evacuation efficiency of personnel in the building is improved.Based on the above studies,feasible measures for evacuation optimization of large public buildings are proposed from the aspects of architectural design,building structure,evacuation organization and personnel capacity,etc.,so as to provide reference for evacuation of large public buildings,so as to reduce casualties and property losses to the greatest extent.