Engineering and Technology Journal

Abstract

The equivalent or the “effective” diameter or size is a well-known parameter in soil
classification and permeability determination. Hazen (1892) on the basis of his study of
filter sands found that the diameter that which 10% by weight of soil grains are finer may
cause same effects as the given soil. Denoted as D10, Hazen called this diameter the
“effective diameter”.
The goal of this study is to determine the value of the percent finer that corresponds
to the equivalent diameter of soil grains that may be used directly to calculate as accurate as
possible the surface area of the soil solids. The equivalent or the effective diameter would
certainly vary according to the gradation of the soil grains, the wider the range of particle
diameters included in the soil matrix the smaller would be the effective diameter.
It was concluded that the effective particle diameter of a soil can be related to other
soil properties such as the liquid limit, plasticity index, the unconfined compressive strength
and the standard penetration test number of blows (N).