Badania nad wpływem nieregularności kształtów cząstek żwirów na wartości współczynnika filtracji

In the paper results of soil permeability determined in permeability coefficient apparatus and with empirical formulas were presented. In experiments two clayey gravels with the same grain size distribution, but different grain shape were used. Some random selected particles from fraction 10-20mm of each soil were measured. For these particles the index of angularity was determined. The index was referenced to the model particles from the Krumbein’s tables. Laboratory tests were carried out with ITB-ZW k2 apparatus at 4 compaction indexes and 4 hydraulic gradients. Results have shown angularity of particles significantly influent on remarkable diversity of void ratio. Three times increase of permeability in soils with rounded particles comparing to soils with angular particles was indicated. It is result of horizontal packing of flat particles in compaction process. This effects some part of pores between the solid particles do not participate in flow in the soil specimen. The highest convergence of laboratory permeability tests results for clayey gravels was obtained with the Slichter’s formulas and the Beyer’s tables.