Study On "Safety-Risk-Accident"Transition Boundary In Building Construction System

The statistics of Ministry of Housing and Urban-Rural Development on the number of urban accidents and deaths each year show that the security situation in China's construction industry is still grim.How to effectively reduce the occurrence of construction accidents and maintain the safe and stable operation of the construction system is an urgent issue.The theory of trajectory crossover and energy transfer theory point out that the accidents happen when a large amount of energy released by the system's risk factors interacts with each other in a certain time and space to the receivers because of unsafe behavior and uneasy behavior of the human beings The transfer of energy exceeds the receiver's limit will lead to accidents.So,the occurrence of an accident is the result of a variety of risk factors coupled.The construction system is always faced with a changing environment,which is in a high degree of uncertainty.The interaction of risk factors always occurs.When the interaction,that is,the risk coupling value reaches a certain boundary or reaches a certain interval,Lead to building safety accidents.According to the concept of mutation,the continuously changing risk factors always occur in a coupling state,which makes the system maintain a dynamic and stable operating condition.However,as the degree of risk coupling changes,when the coupling value reaches a certain threshold and enters a certain interval,Will lead to a sudden change in the system's security status,resulting in the generation of security incidents.So,from catastrophe theory perspective,based on the identification of the risk factors affecting the construction system,this paper quantifies the coupling degree of risk factors by building the risk coupling degree model of the building construction system,so that when the risk factors are dynamically changing,the evolution mechanism and transformation boundary of "safety-risk-accident" three-state system are put forward.Finally,preventive measures of construction safety accidents,target intervention strategies and remediation approaches are put forward from the perspective of mutation causes.The main contents of this paper are as follows:(1)Identify the risk factors that affect the building construction systemBased on the theory of "4M" accident,combining with 22 typical cases of construction safety accident and the cause of six common accidents,the risk factors affecting the construction system are analyzed.Based on this,Screening out the main risk factors that affect the construction system,and laying the foundation for the fourth chapter quantitative coupling degree of risk factors.(2)Construct a computational model of risk coupling degree in building constructionThe fuzzy membership function method is used as a tool to construct the calculation model of risk coupling degree of building construction system,and the expression of risk coupling degree which is suitable for building construction system is deduced to quantify the degree of coupling of risk factors.For the fifth chapter,Under the coupling of factors,the evolvement mechanism and transformation boundary of "safety-risk-accident" of construction system are laid.(3)Study on the evolvement mechanism and transition boundary of safety-risk-accident" in building construction systemWith cusp catastrophe model as a tool,the evolution model of building construction system is established.According to the characteristics of critical balance surface,singular point set and bifurcation point set in building construction system,the safety and risk of building construction system under the coupling force of multi-risk factors-Accident "evolution mechanism,and through the method of mathematical analysis,determine the" safety-risk-accident "transition boundary in the building construction system and quantitatively analyze the influence of multi-risk factors on the state of building construction system.