Numerical Simulation Of Wave Dynamic Response And Stability Of Breakwaters On Reclaimed Reef

Coastal area is important for China's import and export trade.It supports China's economic development.In recent years,more and more coastal structures such as breakwaters,submarine pipelines,offshore wind turbines,and oil/gas platforms have been constructed near the coast in China.In order to protect the coastal and offshore structures,breakwaters are often built up in important ports or coastline to reduce the impact and erosion of waves.For the reclaimed coral reef,the reclaimed calcareous sand is loose and nonuniform.The stability of the revetment breakwater determines the stability of the reclaimed calcareous sand,which in turn enhances the stability of the reclaimed coral reef.Would the breakwater still be stable under the extreme wave impact situation?It is meaningful to study the stability of the revetment breakwater on island reef in extreme weather.In this paper,the coupled numerical model based on FSSI-CAS-2D and OpenFoam are used to simulate and calculate the real size revetment breakwater built on a coral reef island.Interaction of wave-seabed-breakwater under extreme wave impact situation(wave height 7m,period 10s)is studied.Moreover,the stability of the breakwater was evaluated in terms of the displacement and stress distribution of the seabed foundation.The following conclusions are obtained:(1)The peak of wave impact force on the breast wall of the breakwater is 327kPa,and the wave impact mostly occurs in the middle and lower part of the breast wall.The maximum horizontal force on the breast wall can reach 262kN/m,and the maximum horizontal force on the slope can reach 200kN/m.(2)At the time t=171.8s,breast wall is permanently rotated clockwise under the impact of a single extreme wave loading,and the rotation angle is 2.3°.The deformation process of the breast wall as follows:The breast wall has a global horizontal displacement at the moment of impact instantaneously.Then the breast wall rotates,pressing the soil behind the wall,at the same time,the bottom of the breast wall moves to the left.This rotational deformation leads to the redistribution of stress in foundation.(3)The vibration amplitude of dynamic displacement of reclaimed foundation decreases with the depth increasing.The foundation settlement under the breakwater is uniform.The soil foundation behind the breakwater is slightly uplifted.Since the displacement and deformation of the foundation and the breakwater are small,it can be considered that the breakwater can be stable under the extreme wave impact situation.In this paper,FSSI-CAS-2D is the first time to be used to simulate complex real seabed outline.For the purpose of complex boundary modeling and FSSI-CAS-2D model promotion,a Graphical User Interface(GUI)based on C++has been developed,which could be used for the dynamic analysis of the interaction of wave/earthquake,seabed and breakwater.