Study of Using Gabion to Protect Downstream Slope of Stone Weirs

Abstract

In the present research, the stability of stone weirs protected by gabions and subjected to overtopping flow rates under the effect of high flow rates has been studied experimentally. Four weir models with different downstream slopes [1V:2.5H, 1V:3H, 1V:4H, 1V:5H, 1V:7.5H ] were constructed and tested. sixty experiments were carried out for four cases of gabions laying on the downstream slope, laying gabions with one layer and no connections (M-1), laying gabions with lateral connections (M-H), laying gabions with longitudinal connections (M-V), laying gabions with two layers (M-2] using three gravel diameters (11.11,15.9 and 22.25)mm. From the data analysis, many equations were obtained for the estimation of failure unit discharge in terms of equivalent gravel diameter, relative submerged intensity of gabions, gabions layer solidity, and tangent of internal friction angle of gabions, for each case of gabions laying. A simple method was presented for the design of stone weirs protected by gabions in terms of maximum failure discharge with the help of design charts obtained from the present study. Comparing results of the present study with those of other investigations show that stone weirs protected by gabions stand higher failure unit discharge than rockfill and earth weirs protected by gabions.