DWR_3391237

• Document Date: 7/1/1975
• Document Type - Dam Safety: Report
• Division: 3
• Dam ID: 200224
• Subject: HOMESTAKE TAILING POND, LOWER DAM - REPORT OF SLOPE STABILITY REVIEW & ASSESSMENT

V
The quantity and the velocity
of flow of water which will es-
cape through an earth structure
or percolate through soil are
dependent upon the permeability
of the earth structure or soil.
The permeability of soil has
often been calculated by empir-
ical formulas but is best de-
termined by laboratory tests,
especially in the case of com-
pacted soils.
A one -inch length of the
core sample is sealed in the
percolation apparatus, placed
under a confining load, or sur-
charge pressure, and subjected
to the pressure of a known head
of water. The percolation rate
is computed from the measure-
ments of the volume of water
which flows through the sample
in a series of time intervals.
These rates are usually ex-
pressed as the velocity of flow
APPARATUS FOR PERFORMING PERCOLATIONS TESTS
in feet per year under a by- -
Showa teats in progress on eight samples simultaneously.
draulic gradient of me and at
a temperature of -20 degrees Centigrade. The rate so expressed may be adjusted for any set of conditions involving
the same soil by employing established physical laws. Generally, the percolation rate varies over a wide range at
the beginning of the test and gradually approaches equilibrium as the test progresses.
During the performance of the test, continuous readings of the deflection of the sample are taken by means of
micrometer dial gauges. The amount of compression or expansion, expressed as a percentage of the original length
of the sample, is a valuable indication of the compression of the soil which will occur under the act ion of load or
the expansion of the soil as saturatim takes place.
METHOD OF PERFORMING PERCOLATION TESTS
GAMES 8 MOORS
Plate A-5