Current Induced Scour Around Single Piles and Pile Groups

In the present study, a series of experiments on the scour depth around single piles and pile groups were conducted. The scour depths around single piles are plotted against flow velocity, and they are compared with the values predicted with HEC-18. The experimental scour depths and the calculated depths agree reasonably well. Then three sets of tests on the scour depth around pile groups were conducted. Pile groups with different arrangements are studied. It is found that the normalized scour depth varies with the gap ratio. To evaluate the normalized maximum scour depth of pile group, equivalent pile diameter is introduced into the equation of single pile scour depth. The equivalent pile diameter is a function of the diameter of a circle representing the cross area of the parallelogram covering the pile group and the gap ratio. With the equivalent pile diameter, the equilibrium scour depth around pile groups can be calculated with the documented equations.