LOCAL SCOUR AROUND NORMAL AND T SHAPE SPUR DIKES

Abstract

A series of experiments were conducted to study the phenomenon of local scour that takes place around a single spur dike installed as a river training structure on straight channel. The objective of this thesis is to study and understand the phenomena of scour around the foundation of spur dike for different shapes at different orientation of flow. The comparison is done of dimensions of scour hole (maximum scour depth, length of scour in upstream side, length of scour in downstream side, and the scour length in transverse direction) for normal and T shape spur dike with different orientation angle. By comparing the scour hole dimensions we can investigate for which orientation angle the scour is minimum for the both type of spur dike. If the scour around the dike foundation is underestimated then the structure will fails or if the scour around spur dike is over estimated than the structure will became uneconomical so that by analyzing the shapes and geometry of scour holes of different cases we can accurately design the foundations of spur dikes at river sites for bank protection. All tests were held under clear water condition, using a horizontal bed consisted of non-uniform sandy soil (Yamuna sand) in the hydraulic laboratory at Delhi Technological University, Delhi. Several equations via graphs were obtained to compute the relative maximum scour hole depth and scour length with different orientation for normal and T shape spur dikes.