Document Type: Original Article
Assistant Professor, Department of Civil Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran
MSc. in Hydraulic Structures, Department of Civil Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran
Check dams are one of the structures used to control debris flows. In this study, in order to evaluate the effect of hydraulic parameters on debris sediment trapping rate by the slit trapezoidal check dams with different angles, and to develop an empirical relation for determination of trapping coefficient of the dam reservoirs, three physical models of the check dams were used. The tests were performed on a shapeable flume with 15, 20 and 25 ° slopes, under 20, 25 and 30 liters per minute flow rates, 60, 75 and 90 degrees of check dam angles to the horizontal and for a sediment aggregate with a non-uniform gradation. By determination of the effective dimensionless parameters, the effect of these parameters on debris sediment trapping rate was evaluated by plotting diagrams. The analysis of experiments showed that, the trapping rate of the check dam increased by decreasing the channel slope, increasing the check dam spillway height and decreasing the check dam angle. Different relations were evaluated using linear and non-linear multivariate correlation analyses of dimensionless parameters, and a multivariate relation for determination of the sediment trapping coefficient was proposed.