Study On The Safety Risk Of Deep Water Foundation Construction Of Long-span Cable-stayed Bridge Based On System Dynamics

Cable-stayed bridge,as the most important bridge across rivers,lakes,seas and other deep-water terrain in China,has been developed rapidly in recent years.With the rapid development of cable-stayed Bridges,the construction safety has been paid more and more attention by the society.The deep-water foundation construction of long-span cablestayed bridge is characterized by numerous procedures,complex technologies,sensitive to the environment of the construction area and long construction cycle,so there are a lot of safety risks in the construction process.Strengthening the control and management of safety risks in the deep-water foundation construction is an important guarantee to ensure the smooth realization of the engineering construction objectives.However,at present,the theoretical research on safety risk of deep-water foundation construction of long-span cable-stayed Bridges and the scientific safety risk management theory of deep-water foundation construction are still relatively weak in China,which is not compatible with the existing theoretical research on safety risk management of deep-water foundation construction of long-span cable-stayed Bridges in engineering practice.Therefore,the research on safety risk assessment of deep-water foundation construction of long-span cable-stayed bridge based on system dynamics theory has great engineering practical and theoretical significance for further improving and enriching the safety risk management theory of deep-water foundation construction of long-span cable-stayed bridge.At the same time,the theory and method of system dynamics can be used for reference in bridge risk and other risk research fields.Firstly,this paper makes an in-depth analysis of the construction safety risk characteristics brought by the technical and economic characteristics of deep-water foundation construction of long-span cable-stayed bridge,analyzes the impact relationship of each risk,establishes the safety risk space of deep-water foundation construction of long-span cable-stayed bridge.Furthermore,establishing a safety risk identification model for long-span cable-stayed bridge deepwater foundation construction based on fuzzy theory and ranking the safety risk of each layer in the space.Secondly,based on the theory and method of system dynamics,a safety risk assessment model for construction of deep-water foundation of long-span cable-stayed bridge is established.On the one hand,the model is applied to evaluate the safety risk of deepwater foundation construction by investigating the variation trend of total risk and sub-risk risk value.On the other hand,by changing the control efficiency of different risks,the different sensitivity of risk control efficiency can be evaluated.At the same time,by gradually increasing the proportion of important risk control investment,the impact of different risk management resource investment schemes on the change of risk level can be investigated,so as to optimize the risk management resource investment scheme.This paper develops the concept of general risk assessment by establishing a risk assessment model,and forms a new concept of integration from risk assessment to risk management and control optimization.Thirdly,from the Angle of human risk,material risk,management risk,environmental risk and technical risk,the corresponding risk control measures are put forward for the safety risk of construction of deep-water foundation of long-span cablestayed bridge.Finally,taking a long-span cable-stayed bridge 2 # and 3 # main piers deepwater construction safety risk research,for example.Through the simulation results,it is concluded that the project is finally at the significant risk level and the risk value is 18.08.The control efficiency of the five risks is sensitive to the total risk from high to low:human risk,material risk,management risk,technical risk,environmental risk;The optimal risk control schemes are: human risk 35%,material risk 35%,management risk10%,environmental risk 10% and technical risk 10%.