Experimental research on sacrificial spur dikes to reduce scouring.

Yasin Jaafari, Abdollah Ardeshir, Hojat Karami

Thursday 2 july 2015

12:00 - 12:15h at Amazon (level 1)

Themes: (T) Water engineering, (ST) River and coastal engineering

Parallel session: 11B. Engineering - River

The important role of spur dikes (SDs) in indirect protecting methods in river engineering made it desirable to run experiments to increase the efficiency of SDs. In the former experiments it has been seen that SDs had special effects on each other which was depended on stream conditions and also mechanical dimensions of SDs. Along this, Previous experiments on SDs resulted to install an SD with longitudinal proportion of 0.6 to the main SD and also a distance proportion of 2.5 from the first SD named protective SD. Investigation showed satisfactory results on scouring decrease factor in comparison with other taken methods such that for the first SD to the third results orderly were : 65.5 ,89.9 ,69.9 %. In spite of this results, increasing scouring around the protective SD interfered with it’s effect on the scouring decrease of the series of SDs. SO this investigation was conducted to save the protective SD and also stabilize it’s role which resulted an smaller SD with longitudinal proportion of 0.2 to protective SD named sacrificial SD which located in front of protective SD. Sacrificial SD not only has a sustainable effect on decreasing the scour depth around protective SD and make it workable during long time periods, but also decreases it for the whole series of SDs which orderly are: 48.8, 30, 100%. In this experiment to determine the optimal design parameters, various angles of sacrificial SD were experimentally tested under clear-water condition(U/Ucr=0.95) in a straight river reach and a fixed flow depth.