Wave Stability Study of Riprap-Filled Cells; Hydraulic Model Investigation.
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS HYDRAULICS LAB
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Both two-dimensional and three-dimensional hydraulic model investigations were conducted to test the stability of a new streambank protection concept when exposed to short-period wave attack. The concept, referred to as Riprap-Filled Cells, consists of containerizing riprap in various sizes of cells. Based on the 14-scale modelportotype model tests and results for the riprap-filled cells placed on IV-on-2H stream bank slopes that are assumed to be stable and imperable and for angles of wave attack of 90, 60, and 30 deg, it is concluded that a one-ft-cube cells full and half-full of 0.6-to 4.6-lb riprap are stable no streambank exposure for 2.0-sec, 1.0-to 1.75-ft. 4.0-sec, 1.0-to 3.0-ft, and 6.0-sec, 1.0-to 2.5-ft nonbreaking waves b rectangular cells half-full of 0.6-to 4.6-lb riprap are stable for nonbreaking wave heights up to and including 1.5 ft for wave periods of 2.0 and 6.0 sec. Wave heights exceeding this produce spot exposures of the streambank c rectangular cells full of 0.6-to 4.6-lb riprap are stable for 6.0-sec, nonbreaking waves up to and including 2.0-ft. Wave heights exceeding 2.0-ft produced spot exposures of the streambank d both runup and rundown on all sections tested appear to be functions of wave steepness, relative depth, and angle of wave attack. The angles of wave attack, listed in descending magnitudes of runup and rundown produced, are 60, 90, and 30 deg.
- Civil Engineering