Experimental study on local scouring of submerged spur dike head under bottom protection condition

Submerged spur dike is a kind of typical navigation project regulating structure. During the project implementation, the protection of local scouring near the head is especially important. In order to study the characteristics of local scouring of submerged spur dike head under bottom protection condition, this study adopted undistorted model experiment method and focused on studying the variation response rules of the form of the local scour pit of submerged spur dike head under bottom protection condition, its depth and the bottom protection width. The result indicates that the local scour pit of the head under bottom protection condition is near the bottom protection edge. When bottom protection edge is less than 20 m, the variation of the maximum scour depth is relatively small, but the scout pit's position is away from the dam body. The variation rule of the maximum scour depth with the bottom protection width can be expressed with exponential relation. Based on principle of dimension analysis, this study established a formula to calculate the maximum local scour depth of submerged spur dike under bottom protection condition on riverbed made of sand.