Fire Scenario Evolution Reasoning And Disaster Risk Assessment In Urban Commercial Complexes

With the development of the economy and the improvement of living standards,the number of urban commercial complexes has grown rapidly.The commercial complexes that integrate various functions are very convenient and can quickly meet the needs of people’s daily life.However,While commercial complexes bring convenience to people,there are also a lot of hidden dangers,such as the large scale of buildings,high density of people,many combustibles and strong chain reactions of disasters.Once a fire breaks out in a commercial complex,it is easy to cause continuous evolution due to the influence of various factors,resulting in huge property losses and casualties.From the perspective of the evolution reasoning and disaster risk assessment of commercial complex fire scenarios,this paper identifies key evolution scenarios by identifying the fire evolution factors of commercial complexes,and constructs a scenario evolution inference model based on the coupling of emergency response and fire risk factors.The fire risk information obtained by scenario evolution inference realizes the dynamic risk assessment of commercial complex fires,and provides a reference theory for the daily fire management,emergency plan preparation,emergency drills,fire safety management and fire accident investigation of commercial complex business units.and technical support.The main research contents and conclusions are as follows:(1)Based on historical accident case statistics and investigation and analysis,use grounded theory to identify the fire evolution factors of commercial complexes.Firstly,the structure and danger of commercial complexes are analyzed and studied in-depth,and the impact process of commercial complex fires is preliminarily clarified;Secondly,the direct causes and disaster types of commercial complex fires are obtained through the statistical arrangement of accident cases;Finally,combined with literature review,expert interviews and typical case analysis methods,the hazard-causing factors,hazard-pregnant environment and hazard-bearing bodies were obtained by using three factors of fire evolution that grounded theory’s open decoding,spindle decoding,selective decoding and theoretical saturation test.(2)Based on the identification of fire evolution factors in commercial complexes,a scenario evolutionary inference model based on the coupling of emergency response and fire risk elements was constructed by using methods such as association analysis,case reasoning,risk coupling analysis,Bayesian network,and triangular fuzzy function.Firstly,use the correlation analysis method to find the factors with strong correlation in the fire evolution,so as to determine the key evolution scenarios,build the historical building fire accident case database,and use the case reasoning technology to find the buildings that are similar to the actual situation of the target commercial complex.The fire evolution process of the target commercial complex determines the scenarios to be supplemented by the target commercial complex,that is,the personalized scenarios.Combining typical scenarios and personalized scenarios,determine the fire evolution scenarios of different commercial complexes;Secondly,through the analysis of the fire evolution characteristics of commercial complexes and the coupling of scenario evolution,the construction of different fire detection,alarm,automatic sprinkler system fire extinguishing,Fire scenario evolution network under emergency response measures such as personnel rescue and evacuation;Finally,using the triangular fuzzy function,Bayesian network,N-K model and other calculation methods to obtain the path with the largest fire evolution probability after a commercial complex fire occurs,and obtain evolution information and key prevention and control nodes,and using historical commercial complex fire accident cases for reliability verification.The evolutionary reasoning model fully considers the effectiveness and efficiency of emergency response measures such as fire detection,alarm,automatic sprinkler system fire extinguishing,personnel rescue,and evacuation.The coupling between scenario elements makes up for the limitation that current evolution analysis only connects causal elements.(3)According to the evolution information and key prevention and control nodes obtained from the coupling relationship of fire evolution factors of commercial complexes and scenario evolution reasoning,from the perspective of the whole disaster chain,using methods such as coefficient of variation,structural entropy weight and gray clustering to achieve commercial integration dynamic risk assessment of body fire.Firstly,the factors with strong coupling in the evolution process are regarded as the initial evolution risk,and then the continuous evolution risk information of the commercial complex fire is obtained according to the scenario evolution inference model,and the commercial complex is constructed from three aspects: the initial evolution risk,the continuous evolution risk and the final risk.The fire dynamic risk evaluation index system has obtained 3 first-level indicators,7 second-level indicators and 29 third-level indicators;Secondly,the scoring rules of the index system are formulated according to relevant laws and regulations to achieve unified evaluation standards;Finally,the combination of structural entropy weight method and variation coefficient method is used to calculate the index weight,and the upper and lower limit grey clustering risk assessment model is constructed to judge the fire evolution risk level of commercial complexes.(4)Two typical commercial complexes in Beijing are selected for empirical research.Firstly,through empirical analysis,the path with the largest fire evolution probability,key risk prevention and control nodes and fire evolution risk levels after the occurrence of fire in Commercial Complex A and Commercial Complex B are obtained;Secondly,according to the comparison between the evaluation results and the actual situation of the two commercial complexes,it is found that the fire evolution risk level of the commercial complex is in good agreement with the actual situation,which shows that the fire scenario evolution reasoning and evaluation method in this paper is feasible and effective;Finally,according to the key evolution nodes of the two commercial complexes,targeted risk prevention and control countermeasures are put forward.At the same time,it summarizes the current key points of fire risk management and control in commercial complexes,and gives corresponding risk prevention measures,which have certain guiding significance for the business units of commercial complexes to strengthen daily fire safety management,fire prevention,preparation of emergency plans and selection of emergency drill scenarios.