RELATIONS OF PERMEABILITY
TO PARTICLE SIZE OF HOMOGENEOUS AND HETEROGENEOUS SANDS AND
GRAVELS

Benjamin Panganiban Reyes

ABSTRACT

The purpose of this study was to
determine the relations of permeability
to particle size and particle size
distribution of sands and gravels.
Permeability was determined for
homogeneous samples (one grade size of
Wentworth classification system) and
heterogeneous samples (mixtures of two
or more of the homogeneous samples,
generally in equal amounts by weight). A
constant-head permeameter was used.

The results show that (1) the time for a
permeameter sample to reach full
saturation is directly proportional to
the effective size; (2) the permeability
of homogeneous sands is equal to the
1.76th power of the effective size
multiplied
by 11,279.

k = 11,279 D_{10}^{1.76}

The permeability of heterogeneous sands
falls fairly close to this equation. A
field worker may be able to establish
roughly the value of permeability based
on approximate mechanical analysis; (3)
the permeability of homogeneous sands is
proportional to the 1.93rd power of the
median diameter multiplied by 9,034.

k = 9,034 Md^{1.93}

The permeability of heterogeneous sands
does not fall close to this equation;
(4) the permeability of heterogeneous
mixtures of sands and (or) gravels is
controlled by the permeability of the
finest sand in the mixture; (5) no
simple relations of permeability to
uniformity coefficient, sorting
coefficient, and porosity could be
determined.

Geological
Society of the Philippines

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