ГИДРАВЛИЧЕСКИЙ РАСЧЕТ РЕЗЕРВНОГО ВОДОСБРОСА (ВОДОСЛИВА С ШИРОКИМ ПОРОГОМ)

Abstract

Purpose: to carry out hydraulic studies and calculations of a reserve spillway structure (broad-crested weir) of a rockfill dam. Materials and methods. Current studies show that in open channels the regime of fluid movement can be different, and the boundary surfaces of the channel in some cases should be considered as hydraulically smooth, in others – as hydraulically rough. The broad-crested weir of rectangular and trapezoidal section is considered. To determine the experimental discharge coefficient of the reserve spillway of an earth rockfill dam, the known dependences for unflooded broad-crested obtained by A. R. Berezinsky and D. I. Kumin were used. Results. Based on the results of comparing the calculated flow coefficients with the experimental data of other authors, close values with the data of A. R. Berezinsky and D. N. Kumin were obtained. At the same time, the values of the discharge coefficients of the water discharge according to Berezinsky and Kumin are in the range of 0.339 and 0.324, which confirms their compliance and high accuracy. The results of the calculation of the filtration flow rate through the rockfill of the dam with a reserve spillway are the filtration flow rates in the range of 726.81–2260.76 m³/s. Conclusions. The performed calculations showed that the values of the discharge coefficients of the weir of a trapezoidal section correspond to the data obtained by A. R. Berezinsky and D. I. Kumin. At the same time, the values of the spillway discharge coefficients by Berezinsky and Kumin are within acceptable limits, which confirms their compliance. The average flow velocities passing through the broad-crested weir were: for profile 1 – 3.76 m/s, for profile 2 – 0.612 m/s, for profile 3 – 2.13 m/s.