Scour around Spur Dike in Sand–Gravel Mixture Bed

• Published in: Water (Basel) Vol. 11; no. 7; p. 1417
• Main Authors: Pandey, Manish, Lam, Wei Haur, Cui, Yonggang, Khan, Mohammad Amir, Singh, Umesh Kumar, Ahmad, Z.
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.07.2019
• Subjects: Armor; Bridges; Civil engineering; clear-water scour; Creeks & streams; Critical velocity; Empirical equations; Equilibrium; Equilibrium conditions; Error analysis; Experiments; Flow velocity; Froude number; Gravel; Hydraulics; maximum equilibrium scour depth; Nonuniformity; Parameters; Rivers; Sand; Sand & gravel; sand–gravel mixture; Scour; Scouring; Sediments; Sensitivity analysis; spur dike; Spur dikes; Standard deviation; Uca; Water depth; India
• ISSN: 2073-4441; 2073-4441
• DOI: 10.3390/w11071417

Scour is the main cause of failure for spur dike. The accurate prediction of scour around spur dike is essential to design a spur dike. The present study focuses on the maximum scour depth in equilibrium condition and parameters, which influence it in a sand–gravel mixture bed. Outcomes of the present experimental study showed that the non-dimensional maximum equilibrium scour depth increases with critical velocity ratio (U/Uca), water depth-armour particle ratio (h/da), Froude number for sediment mixture (Frsm), water depth-spur dike length ratio (h/l), and decreases with increase in armour particle-spur dike length ratio (da/l). The maximum scour depth is proportional to dimensionless parameters of U/Uca, h/da, Frsm, h/l, but the scour depth is inverse proportional to da/l. Scour around spur dike in a sand–gravel mixture is mainly influenced by the property of the sediment mixture. The scour increases with decrease in non-uniformity of the sediment mixture. A non-linear empirical equation is proposed to estimate the maximum scour depth at an upstream nose of rectangular spur dike with a maximum error of 15%. The sensitivity analysis indicates that the maximum non-dimensional equilibrium scour depth depends on Frsm, followed by the secondary sensible parameters da/l, h/l, and h/da.