Emergency Protection Design Method And Performance Analysis Of Floating Breakwater In Super-designed Extreme Sea Conditions

Compared with the traditional fixed breakwater,the floating breakwater has the advantages of low engineering cost,simple construction and convenient layout,so it has received much attention in recent years.Floating breakwaters are anchored by mooring systems,so their safety against harsh sea conditions is critical.Under normal circumstances,the safety of floating breakwaters under design sea conditions is guaranteed.Then,in actual engineering,due to the frequent occurrence of extreme weather,the probability of occurrence of super-design sea conditions increases,and once ultra-design sea conditions occur,the guarantee floats.The safety of breakwaters and the minimization of losses are important.In this paper,the emergency protection design method of floating breakwater under super-design sea conditions is studied.Based on this,the hydrodynamic performance analysis of the floating breakwater under the action of emergency protection system is carried out,and the effect of emergency protection method is studied.(1)Based on the situation of the sea area where the floating breakwater is located,environmental conditions are determined.According to the configuration and basic parameters of the floating breakwaters tested in the South China Sea,the rubber ring emergency protection method and the anchor chain emergency protection method are designed.The preliminary concept design of the two emergency protection methods was carried out,and the basic parameters of the two emergency protection devices were given.Finally,the working principles and advantages of two kinds of emergency protection methods are introduced,and two sets of emergency protection mooring system design schemes are given.(2)Taking the floating breakwater under the emergency protection system as the research object,use the finite element software WORKBENCH to establish the wet surface model of the floating breakwater,and then use the ANSYS-AQWA software to first obtain the frequency domain floating by calling the AQWA-LINE module.Additional mass,radiation damping,motion response amplitude operator(RAOs),first-order wave force,and constant drift force of a breakwater at different water depths and different wave angles.Then according to the environmental parameters,the AQWA-DRIFT module is called to analyze the time-domain hydrodynamic performance of the floating breakwater without emergency protection system,and verify the importance and necessity of the emergency protection method for the floating breakwater under the super-design limit sea state.(3)Taking the floating breakwater under the rubber ring emergency protection system as the research object,the ANSYS-AQWA software is used to calculate the time domain coupling of the floating breakwater under the rubber ring emergency protection system,and the floating breakwater is studied in the rubber ring type.Hydrodynamic performance under emergency protection systems.The WORKBENCH software is used to simulate the tensile force of the rubber ring emergency protection device,analyze the effect of the rubber ring emergency protection method,and verify the rationality and feasibility of the rubber ring emergency protection method.(4)Taking the floating breakwater under the anchor chain emergency protection system as the research object,using ANSYS-AQWA software to calculate the time domain coupling of the floating breakwater under the anchor chain emergency protection system,and study the floating breakwater in the anchor chain Hydrodynamic performance under emergency protection systems.At the same time,combined with the research on the emergency protection mooring system of the floating breakwater,the effect of the anchor chain emergency protection method is analyzed,and the rationality and feasibility of the anchor chain emergency protection method are verified.