Investigation of effect lengths and angles of the control devices below the hydraulic structure

Abstract This study investigated the effect of reducing seepage under a hydraulic structure. This article aims to find positional equations for the control devices that reduce the seepage under the hydraulic structure. Using lengths and angles of sheet-piles under the hydraulic structure where the sheet-pile was placed up- and downstream, respectively, upon the hydraulic structure with anisotropy soil hypothetically affects both uplift pressure and seepage values. The experiments were conducted in two cases: in the first case, a couple of sheet-piles were oriented to the upstream passage; while in the second case, they were oriented to the downstream. Then, the second case was compared with three sheet-piles placed upstream, downstream, and intermediate to the passage. For each experiment (at the hydraulic toe position), the major affecting parameters such as the uplift pressure, gradient exit, and outlet flow rate were found. A correlation equation to correlate the exit gradient and discharge parameters was developed.