Consumption of Solid Runoff during Erosion of Bottom Slope of Soil Dam

Erosion is divided into two stages in accordance with the accepted design scheme for erosion of a soil dam during overflow. The paper deals with the first stage, when the downstream thrust prism is washed out. The key factor in calculating erosion deformations is the choice of the solid flow rate formula. Studies show that the mechanism of formation and transportation of solid runoff during erosion of dam models from sandy oils is very similar to that previously described by many authors for the condition of river channel erosion. The peculiarity of the process is that the erosion occurs at high speeds. Therefore, solid runoff almost immediately goes into a suspended state. To select the required formula, experiments have been carried out on models of dams made of sandy soils having various granulometric composition. It has been established that at high velocities under the considered conditions, the value of the solid waste flow rate depends solely on hydraulic characteristics of the flow. The influence of physical and mechanical properties of the eroded soil on the value of the flow rate of solid runoff is insignificant, and they may not be taken into account. Calculations have been carried out using formulas known from river hydraulics, which show that none of them gives sufficient convergence with experimental data. Based on the analysis of a large number of experimental data, a formula for the discharge of solid runoff for erosion conditions of dam models during overflow has been obtained in the paper. This has taken into account the fact that the dam erosion by the overflow has a high degree of stochasticity and is difficult to describe theoretically. This is especially evident in conditions of spatial erosion, when, simultaneously with the classical erosion of the bottom, the sides of the eroded hole periodically collapse, which is difficult to take into account in the calculations.

1. Bogoslavchik P. M. (2018) Calculation Model of Soil Dam Wash-Away due to Overflow. Nauka i Tekhnika = Science and Technique, 17 (4), 292–296. https://doi.org/10.21122/2227-1031-2018-17-4-292-296 (in Russian).

2. Grishanin K. V. (1977) Channel Sediment Discharge in Rivers with a Sandy Bottom. Channel Processes and Methods of their Modeling. Leningrad, Energiya Publ., 8–14 (in Russian).

3. Goncharov V. L. (1962) Channel Flow Dynamics. Leningrad, Gidrometeoizdat Publ. 373 (in Russian).

4. Studenichnikov B. I. (1964) Flow Erosion and Channel Calculation Methods. Moscow, Stroyizdat Publ. 184 (in Russian).

5. Lapshenkov V. S. (1979) Forecasting of Channel Deformations in the Basins of River Waterworks. Leningrad, Gidrometeoizdat Publ. 239 (in Russian).

6. Levi I. I. (1957) Channel Flow Dynamics. Leningrad, Gosenergoizdat. 342 (in Russian).

7. Guidelines for the Calculation of Siltation of Reservoirs in Construction Design. Leningrad, Gidrometeoizdat Publ. 55 (in Russian).

8. Abalyants S. Kh. (1958) Suspension Movement in Open Streams. Trudy SANIIRI [Proceedings of Central Asian Research Institute of Irrigation]. Tashkent, 96, 3–156 (in Russian).

9. Grishanin K. V. (1974) Stability of River Bed and Canals. Leningrad, Gidrometeoizdat Publ. 144 (in Russian).

10. Tishchenko A. I., Mikhailov E. D. (2016) The Results of Studies of the Transporting Ability of the Flow During Erosion of the Sand Insert of the Reserve Spillway. Puti Povysheniya Effectivnosti Oroshaemogo Zemledeliya [Ways to Improve the Efficiency of Irrigated Agriculture]. Novocherkassk, Publishing House of “Russian Scientific Research Institute for Land Reclamation Problems”, 62 (2), 140–149 (in Russian).