Study On Dynamic Response Of Seabed Under Waves And Liquefaction Resistance

Wave is one of the main factors affecting the stability of offshore structure.With the wave actions,the pore water pressure and effective stress in the seabed are changed,resulting in deformation and even liquefaction of the seabed,which has a great influence on the stability of the structure.Based on the open-source finite-fluid software OpenFOAM,a CFD-CSD model is established to simulate the seabed response around the composite bucket foundation of offshore wind turbines,and the anti-liquefaction measures are discussed.The main conclusions and results are as follows:(1)Based on the open source OpenFOAM,a numerical model of wave-seabed-structure interaction has been established.The numerical wave tank is governed by the Reynolds-Averaged Navier-Stokes equations and applied the momentum source function to generate waves.The volume of fluid method is used to track the water free-surface.Furthermore,the dynamic response model of seabed is formulated on the basis of Biot's consolidation theory and combined with the plasticity Mohr-Coulomb constitutive relation.(2)The dynamic response of seabed under wave action is investigated,and the results agreed well with the experimental and analytical results.Furthermore,the porous media model was added to simulate the dynamic response of the seabed around the submerged breakwater.The results show that the model can well simulate the dynamic response of the seabed considering the influence of the structure.(3)Select the hydrological conditions of the actual project in Xiangshui area,and study the dynamic response of the seabed around the bucket foundation under wave action.The numerical results show that the liquefaction of seabed mainly occurs in the wave trough,and the maximum liquefaction depth appears on the wave front of the bucket foundation.(4)The rock-covered layer were taken on the surface of the seabed around the bucket foundation,and the ant-liquefaction ability was analyzed and evaluated by numerical simulation.It is found that the overburden rock layer can change the initial stress state of the seabed without significant attenuation of the wave dynamic pressure.The rock layer can effectively reduce the liquefaction depth of seabed.and the smaller the porosity,the stronger the liquefaction resistance.