Study On Construction Risk Early Warning Of Self-propelled Trailing Suction Dredger Under Typical Scenarios

As the carrying capacity and tonnage of ships continue to increase,higher requirements are placed on the water depth and navigability of harbor channels.At the same time,due to the complexity of marine environment,the harbor channel often has the problem of sediment re-siltation,and the harbor channel needs regular or irregular dredging maintenance to ensure its navigability.For this reason,a large number of self-propelled trailing suction hopper dredger are put into the construction and maintenance works of harbor waterways.However,typical accidents such as ship collision and rake pipe damage caused by these dredgers during the construction of waterways occur from time to time,bringing great risks to navigation safety and dredger operation safety itself.Therefore,this paper carries out early warning research on the risk of self-propelled trailing suction hopper dredger channel construction,and proposes a ship collision risk early warning model and rake pipe damage risk early warning model based on fuzzy logic method and Bayesian network,and the main work contents and conclusions are as follows:(1)Combined with the hull structure of self-propelled trailing suction hopper dredger,construction work environment and construction work characteristics,through literature knowledge,practical research and expert consultation,analyze the collision risk characteristics and construction work rake pipe damage risk characteristics during construction work,to identify the self-propelled trailing suction hopper dredger two typical scenarios of construction work safety risks to provide the basis.(2)Based on the analysis of collision risk characteristics,the formula of safe encounter distance for self-propelled trailing suction hopper dredger is summarized and analyzed,and a collision risk index system considering the influence of safe encounter distance,maneuvering performance and environmental factors is established.A ship collision risk warning model is established by fuzzy logic method,and the collision warning model is transformed into an application suitable for engineers’ use.The safe encounter distance and encounter geometry in the collision warning model were verified based on the ship maneuvering simulator,and the verification results were consistent with the expert opinions;in addition,the actual ship practice in the actual engineering projects showed that the collision warning results were consistent with the expert opinions in the typical encounter scenarios.(3)Based on the analysis of the rake tube damage risk characteristics,inductive analysis of rake pipe damage accident type and cause characteristics,the rake pipe damage risk index system was established.By interpretative structural modeling method to get the Bayesian network structure,the use of fuzzy number processing expert opinion to get the Bayesian network of the prior probability and conditional probability,the establishment of Bayesian network-based rake tube damage risk warning model.The actual engineering project of the actual ship practice shows that the model prediction probability of rake pipe damage is 55%,the risk warning level is two,and the warning results are consistent with the expert opinion;in addition,the prediction probability of rake pipe damage in accident cases is above 87%,and the risk warning level is one,which is consistent with the actual situation.