Fluid characteristics of wave-induced liquefied silty seabed and the resulting wave attenuation

Wave-induced liquefaction of silty seabed is a common submarine geological hazard that poses a significant risk to the safety of marine structures. The liquefied seabed exhibits fluid properties and fluctuates with the overlying wave. To investigate the interaction between waves and the liquefied seabed, a wave flume experiment was conducted to simulate the wave-induced liquefaction process. During the experiment, the variation in the fluctuation trajectory and viscosity coefficient of liquefied silt with the wave intensity and liquefaction process were measured. Additionally, the wave energy dissipation due to seabed liquefaction was analyzed. The results indicate that the viscosity coefficient of the liquefied seabed is closely related to the wave intensity and liquefaction process, with the viscosity coefficient of the liquefied seabed being larger in the liquefaction deposition stage than in the liquefaction development stage. Seabed liquefaction can lead to a considerable increase in wave energy dissipation, up to 15 times greater than when the seabed is stable. Furthermore, wave energy dissipation is greater for high waves than for low waves conditions. The primary factors causing wave energy dissipation are the viscosity friction inside the liquefied seabed and the suspended sediment in the upper water column. •Motion trajectory and viscosity coefficient of liquefied silt are measured.•Wave attenuation due to silty seabed liquefaction is experimental and numerical investigated.•Mechanisms of wave attenuation caused by stable/liquefied silty seabed are analyzed.