IMPACTS OF DIMENSION AND SLOPE OF SUBMERGED SPUR DIKES ON LOCAL SCOUR PROCESSES-AN EXPERIMENTAL STUDY

摘要

In this experimental study, the impacts of the slope of the upstream face of submerged spur dikes on scour patterns in the vicinity of the submerged spur dike have been investigated. Associated hydraulic parameters for scour initiation have been studied. The dependence of the criteria for scour initiation and scour patterns on the dike dimensions such as the dike length and height has been assessed. It is found that the maximum depth of a scour hole is localized upstream of the spur dike end. The location of the maximum scouring depth, the end of the spur dike, and the spot with the maximum deposition are nearly aligned and form a line approximately parallel to the flume wall. Results show that the proper selection of a sloped upstream face of the spur dike can significantly reduce the maximum scour depth and scour volume in the vicinity of the submerged spur dike. Equations have been established to describe the dependence of the criteria for scour initiation and the maximum depth of the scour hole on the Froude number of the flow, the blockage of the cross section by the spur dikes, the slope of upstream face of the spur dike, and the grain size of the bed material.