Influence of cohesion on scour at wake of partially submerged spur dikes in cohesive sediment mixtures

ABSTRACTThis study presents the influence of cohesion on scour at wake region of the partially submerged spur dikes embedded in cohesive sediment mixtures consisting of clay-gravel and clay-sand-gravel. The experimental results revealed that the development of scour hole and scouring process around spur dike in cohesive sediment containing sand and gravel were considerably different than that of cohesionless sediments. The geometry and process of scour at the spur dike wake region were found to vary with unconfined compressive strength and clay content present in the mixtures of cohesive sediment. The scour depth decreases drastically with an increase in clay percentage and unconfined compressive strength of the mixtures of cohesive sediment. Using dimensional analysis, equations have been presented for the assessment of scour depth in the wake region of spur dikes embedded in the mixtures of gravel-clay and gravel-sand-clay sediments.