Experimental study on silty seabed scour around the single pile induced by the current

Abstract

In this study, the effects of the current velocity, water content, consolidation strength, and soil particle size on the silty seabed scour around the single pile are studied through flume tests. The liquid limit and plastic limit of the silt are determined through water content tests to calculate the plasticity index. The shear strength and density of the soil were determined through direct shear tests and ring knife methods, respectively. The experimental results indicate that the ultimate equilibrium scour depth of the single pile on silty seabed does not increase or decrease with the increase of water content, but as the water content increases to a certain value, it begins to decrease. The consolidated silty seabed has a substantially smaller scour depth than unconsolidated seabed, and the greater the consolidation strength, the smaller the scour depth, and the more time is needed to achieve scouring equilibrium. The water content and consolidation strength both have an impact on the shape and radius of the scour hole. At high flow rates, the time for the silty seabed to reach the ultimate equilibrium scour depth is greatly shortened. When the flow rate is high, the time history curves of different water contents become more similar. Based on the experimental results, a prediction formula for the scour depth of the silty seabed considering the characteristics of fluid and soil is established. The error of the new formula is less than 20%, which can provide reference for pile scour protection on the silty seabed.