This research investigates open channel protection using gabions by conducting a series of laboratory tests on a trapezoidal channel with fixed width and bed slope. In this study, values of failure flowrates are obtained with a description of failure mode under the effect of changing channel side slope, gravel mean diameter, and number of protection layers. Three channel side slopes are tested (1V:1.5H, 1V:2H, and 1V:2.5H), with three gravel diameters (11.1, 15.9, and 22.25)mm, for one and two layers of protection. Two modes of failure have been observed namely sliding and overturning due to the movement of gravel inside the gabions.
Results showed a direct relation between failure flowrate of protection layer and both gabion weight and number of protection layers. It has been obtained that failure flow rate increases with the decrease of channel side slopes. Equations have been obtained relating failure flowrate with both gabion weight and channel side slope. Empirical equations have been obtained using dimensional analysis to estimate failure flowrate as a function of uniform flow depth and gravel mean diameter. A design method has been proposed to protect channel side slopes using gabions.
Keywords: open channels, gabions