عنوان مقاله [English]
Rockfill dams can be applied as suitable tools for flood control purposes. The appropriate understanding of their hydraulic principles is though inevitable. Through flow in rockfill dams has been investigated by many researches. Flood discharge greater than design discharge however might cause simultaneous through and over flows in such dams which have not yet been studied. In this paper unsubmerged simultaneous through and over flow in flood control rockfill dams has been investigated experimentally. The upstream and downstream side slopes, the material size, the upstream and downstream depth, and the length of the dam have been considered as effective parameters. A flume 10m long, 45cm high, and 30cm wide is used for this experiment. Two hundred and forty physical models have been studied for four lengths (i.e. 50, 70, 90, and 110 cm), two side slopes (i.e. 45 and 90 degrees), three material sizes (i.e. 1.45, 2.1, and 3.05 cm), and ten flow rates (ranging from 4 to 16 L.s-1). Based on the experimental results, a non-linear regressive equation for discharge estimation with a correlation coefficient of 0.936 and root-mean-square-errors of 0.001 has been proposed. Results also showed that flow rate has been directly affected by the ratio of dam height to upstream head, the ratio of material size to dam height and submerged ratio was inversely affected by the ratio of dam length to dam height and the upstream and downstream side slopes.