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Zmiany uziarnienia na dnie poniżej budowli piętrzącej

Zawadzki P., Hämmerling M.

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

2008

Vol. 17, No. 2

146--154

The paper presents results of laboratory investigations of local scour in non-uniform non-cohesive bed material below a horizontal solid apron. An experiment of local scouring conducted in a glass-sided rectangular fl ume under clear-water conditions with constant water discharge was performed. In this study several non-uniform soils consisted of the following coloured fractions: 0.5-1.25, 1.25-2.5, 2.5-4.0, 4.0-6.3, and 6.3-10.0 mm were used. Every scour hole had begun just below the solid apron having mild slope and downward concave shape. Similar changes in grain composition were observed in all tests; the hole bottom at the deepest section was covered by the largest grains. During the experiments it was found that bed armour coat had formed in soils with standard deviation of mean grain size σg > 2 and downstream of the maximum scour hole depth, only. Soils with σg < 2 did not create any armour coat, and single coarse grains increased turbulence behind them and accelerated erosion of finer grains.

Local scour in non-uniform bed material below a horizontal solid apron

Zawadzki P., Błażejewski R.

Archives of Hydro-Engineering and Environmental Mechanics

2001

Vol. 48, nr 1

3-17

A two-dimensional mathematical model of local scour in non-uniform non-cohesive soil below a horizontal solid apron is presented. The model parameters were identified on the basis of own experimental laboratory data. Verification of the model, accomplished using other laboratory data, showed fairly good conformity, however, additional verification under field conditions is needed.