Experimental study of local scour around a vertical pier in cohesive soils

Estimation of maximum scour depth is an important factor in designingstructures that are embedded in rivers. using a hydraulic model, the mechanism of localscour around bridge piers embedded in cohesive soils has been studied. experiments wereperformed in a ume; 22 m long, 0.77 m wide and 0.60 m deep, with a pier of 0.1 m indiameter. also, three types of cohesive soil with dierent percent clay were used. whilechanging parameters, such as current velocity, ow depth, initial moisture content, claypercentage, and undrained shear strength, in each experiment, the scour depths weremeasured. the measured data were adjusted by hyperbolic law. using dimensionalanalysis, a relationship between the ultimate scour depth and eective parameters wasdeveloped. finally, the ultimate scour depths obtained by the experiments were comparedwith those calculated by empirical equations