Scour is a natural process which occurs due to morphological changes taking place in river or streams or it is also happening due to presence of manmade structures, e.g., abutments, spurs, and piers. Spur dykes are the hydraulic structures those are employed to divert the flow in order to protect the both banks of the river from possibility of erosion. By changing the local spacing between permeable and impermeable spur dykes, there is a great influence on scour has been found. In this study, sand and gravel in equal proportion are mixed and then used as bed material for experimentation. Firstly, spur dyke having angle of inclination with downstream of the bank at 90°, 75°, and 60° was placed in flume to find maximum scour depth. Secondly, three different arrangements of pile group (having 25, 23, and 15 piles in each group) were placed in front of the spur dyke at 1L, 2L, 3L, and 4L spacing from the spur dyke having above-mentioned angle at each spacing. From experimental results, for spur dykes without protection, maximum scour depth is formed at 90°, while at 60° scour depth is minimum. When protections in form of group pile were used with spur dyke at 90°, 75°, and 60°, the maximum scour depth has reduced for all three cases. It is also concluded that for pile group with 23 piles has exhibited minimum scouring when placed at a distance of 3L spacing with spur dyke placed at 60° of all experiments.

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Local Scour Studies on Spur Dyke with Grouped Piles

  • Arun Goel,
  • Neeraj Pandey

摘要

Scour is a natural process which occurs due to morphological changes taking place in river or streams or it is also happening due to presence of manmade structures, e.g., abutments, spurs, and piers. Spur dykes are the hydraulic structures those are employed to divert the flow in order to protect the both banks of the river from possibility of erosion. By changing the local spacing between permeable and impermeable spur dykes, there is a great influence on scour has been found. In this study, sand and gravel in equal proportion are mixed and then used as bed material for experimentation. Firstly, spur dyke having angle of inclination with downstream of the bank at 90°, 75°, and 60° was placed in flume to find maximum scour depth. Secondly, three different arrangements of pile group (having 25, 23, and 15 piles in each group) were placed in front of the spur dyke at 1L, 2L, 3L, and 4L spacing from the spur dyke having above-mentioned angle at each spacing. From experimental results, for spur dykes without protection, maximum scour depth is formed at 90°, while at 60° scour depth is minimum. When protections in form of group pile were used with spur dyke at 90°, 75°, and 60°, the maximum scour depth has reduced for all three cases. It is also concluded that for pile group with 23 piles has exhibited minimum scouring when placed at a distance of 3L spacing with spur dyke placed at 60° of all experiments.