Author(s): M. Shafai-Bejestan; N. Najafi
Linked Author(s): Mahmood Shafai-Bajestan
Keywords: Spurs; River; Erosion; Scour
Abstract: The most common practice of flow-altering measure for river bank protection is to construct series of spurs. The spur is a structure usually perpendicular to the bank toward the river center to redirect the flow velocity from the bank. The view of the structure perpendicular to the flow velocity is rectangular in shape. The most common problem with this structure is developing a deep scour hole which usually occurs at the toe of the structure and can damage the structure itself. Any structure which can reduce such scour depth is the interest of engineers. In the present study the effect of a triangular spur shape (TSS) on bed topography of river in a straight flume has been investigated. This structure has a sloping crest that extends from the riverbank and forms a low angle with the bank. Series of TSS were attached to the bank with space of 4Le between spurs and was tested under four different flow conditions (Froude number equal to 0.2, 0.22,0. 24 and0.26). For comparison the same tests carried out using regular rectangular spur shape (RSS). Bed topography was measured after each test. The results show that in general the river bed deeper part for both spur shape is shifted toward the center of river. However the scour at the toe of TSS is considerable less than the RSS. Accumulation of sediments in between spurs has been observed with more deposition for TSS.
Year: 2014