Influencing factors on the stability of rockfill barriers

Rockfill dams are economical and effective structures for flood detention and control purposes. The object of this paper is proposing an equation for design of pervious barriers so that enables engineers to determine a stable downstream slope of the dam against overtoping flows. A series of laboratory tests were carried out in a flume with a longitudinal slope of 0.003m/m. The length, width and height of flume were 14 m, 0.6 m and 0.9 m respectively. Eighty eight physical models of rockfill barriers with 50 cm height, 100 cm crest width, 1V:2H upstream side slope and 1V:2.5H to 1V:6 H downstream side slopeswere made using eight different material grading sizes. Using the dimensions analysis technique, an empirical relation for calculating the stable downstream slope was developed in terms of maximum overflow depth, overflow and through flow rates, upstream and downstream water depths difference, bottom width and grading size of dam material. To evaluate the proposed equation, some experimental data were compared with the corresponding results of equation and a correlation coefficient of 0.865 was observed between them