Filtration process in earth fill dam body and its chemical effect on piezometers

Abstract

Estimation of aggressiveness of filtration flow in the dam body is gaining importance in providing the stability of reservoir dam and its parts. In order to estimate the aggressiveness of filtration flow in the dam body it is necessary to know the movement pattern of filtration water in reservoir dam and its effect on dam elements. The article brings up the definition of gradients of filtration flow in the dam body, analysis of the reasons of their change by cross section at the example of Tashkent reservoir dam. Besides, chemical composition of water in piezometers has been analyzed, aggressive effect of sulfate salts on piezometers, and their corrosion have been determined. Measures on systematic piezometer observations are mentioned.

Results and analysis of field research in flood reservoirs in Kashkadarya region

“…Therefore, the reservoirs located in the basins of these rivers are often damaged by floods. It is caused by the accumulation of large amounts of sediments in the basins of water and flood reservoirs built in the river basins [8][9][10][11][12][13][14][15][16][17][18][19].…”

“…In general, it is practically impossible to completely remove the sediments in the upper basin from the flood reservoir zone. However, if appropriate measures are not taken to reduce their amount, such hydropower plants may become completely unusable after several years [8][9][10].…”

“…Parameters of turbid sediments in flood reservoirs, which have been in use for several years, differ sharply from the design calculations. According to the results of the research, the total volume of sedimentary deposits in these reservoirs can be determined as follows [4][5][6][7][8][9][10][11][12][13]:…”

“…According to the analysis of the mechanical composition of sedimentary deposits, the average percentage by particle diameters and their weight is as follows. : d >0.5 mm -0.1 %; d= 0.25-0.5 mm -0.79%; d = 0.1-0.25 mm -2.33%; d= 0.05-0.1 mm -53.22%; d= 0.01-0.05 mm -13.46%; d= 0.005-0.1 mm -8.92%; d<0.005 mm -21.18%; d av = 0.05 mm [4][5][6][7][8][9][10][11][12][13][14][15][16].…”

Using the boundary elements approach to solve the problems of liquid filtration via the dam

“…During the numerical calculation of the problem, the primary free surface position is determined arbitrarily, and, among other things, in all points of this surface q = 0 convention is accepted [9]. The potential value,which was determined for each nodal point of the free surface, is correlated with the liquid surface height [10].If inequality among them is more than the maximal admissible error, this inequality will be algebraically compiled with the area height in the relevant nodular point and new iteration will be conducted [11][12][13].…”