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Sieve Analysis involves passing a soil sample through sieves with successively
smaller holes. Consequently, the method cannot determine individual
particle sizes. It only divides the particles into size. All particles retained
categories bracketed by the sieve opening size on a given sieve in a stack are
larger than the holes in that sieve but smaller than the previous sieve's holes.
By dividing the mass retained on each sieve by the total mass, the percent
of the particles in each size range can be determined are made of woven
wire screen. They are available in many Sieves holes size from 100 mm to
0.037 mm. The smallest practical size is the 0.074 mm #200 sieve, since it is
difficult to even pass water through smaller holes. Occasionally the J1270
sieve (0.053 mm) is used to separate the sand from the silt fraction, but sieve
analysis is usually used only to separate out sand and gravel particles. The
openings in sieves are square. The opening size is the square opening.
Since soil particles distance between two sides of some particles with longer
dimensions will occasionally pass through a given sized opening while others
with a shorter dimension may never become properly oriented to pass
through the sieve analysis data must be accepted with this limitation
opening. Also neither sieve analysis nor hydrometer analysis provides
.
information about the shapes of the particle. A more serious limitation of
sieve analysis of soil materials is their elemental the difficulty of separating
all particles into grain without crushing some of the grains. Also, finer
particles will often adhere, due to electrostatic forces, to larger particles, and
thuswill be measured as larger-sized particles.
The best method of performing sieve analysis on soils is to pulverize an air-
dry sample, then wash the fines through a 0200 sieve. That 1frtion of the
sample retained on the #200 sieve is easy to pulverize after oven drying and
no fine particles will remain to attach to the larger particles.
30 | Soil Engineering Practical Workbook