Filtration of the dam of the PSPP upper basin

Introduction. Ground dams and levees made of fine-grained soils are very common structures. Their widespread use in hydraulic engineering is explained by their cost-effectiveness due to the use of local materials. Clay soils are often used in such structures both for laying in the prisms of the dam and for the installation of anti-filtration elements. However, the laying of clay soil is associated with some restrictions related to the climatic conditions of construction. During the rainy period or during the period of snowfall and exposure to negative temperatures, the laying of such soil slows down due to the need to apply special measures, or stops altogether. This affects the time of construction and, ultimately, the cost of construction. The possibility of replacing part of the clay soil of the dam with sandy soil, the laying of which does not depend to such an extent on weather conditions, is considered. However, such a replacement requires additional verification of the structure in terms of its filtration capacity. A study of the filtration regime of the dam of the basin of the PSPP, built using all-weather technology of soil laying, was carried out. The parameters of the filtration flow for various design variants are obtained. Recommendations are given on the choice of an option for an underground dam. The enclosing dam of the PSPP basin made of mixed soils on a non-slip foundation with a height of 32.0 m, laying an upper slope of 1:6.0, and a lower slope of 1:3.5 was considered. 9 design options with various structural elements were considered.Materials and methods. Calculations of soil dam filtration for steady state and unsteady dam regimes were carried out using the numerical finite element method in the local variational formulation using the FILTR software package.Results. As a result of the research, the parameters of the filtration flow were obtained for the considered variants of the earthwork design: the position of the depression curve, the values of the filtration flow rate and the gradient. Recommendations on the choice of design are made.Conclusions. Studies have shown that it is possible to use mixed soil laid using all-weather technology in the prisms of a soil dam instead of part of the clay soil when they are layered. At the same time, the filtration regime of the structure together with the foundation does not cause concern.

earthen dam, filtration flow, depression curve, filtration flow rate, filtration gradient, numerical calculation methods, finite element method