Experimental Study on the Local Scour of Submerged Spur Dike Heads under the Protection of Soft Mattress in Plain Sand-Bed Rivers

Abstract

Submerged spur dikes are widely applied in the channel regulation structures of plain sand-bed rivers such as the lower reaches of the Yangtze River; thus, the issue of local scour protection near regulating structures is especially important for structure design engineering. To further scientific research on the local scour of submerged spur dike heads, we investigated rulers describing the variance of the incoming flow dynamic, scale of the spur dike body, width of river bottom protection, etc., responding to the maximum local scouring depth of a submerged spur dike and the distance between the submerged spur dike and dam axis under the conditions of river bottom protection. According to principles of dimensional analysis, we established computational formulas for the maximum local scouring depth of a submerged spur dike and the distance between the submerged spur dike and dam axis, with consideration of bottom protection works for the remaining soft mattress. These research results not only enrich existing research on the calculation of local scour of channel-regulating structures, but they are also a relevant technical reference for the design of water conservancy and waterway engineering.