CH-2 Lecture 3
CH-2 Lecture 3
CH-2 Lecture 3
CH-2
LECTURE THREE
Physical Characteristics of
Soil Soils
Mechanics-I
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Wi
% Retained on ith seive 100
W
i
% Finer than ith seive 100 (% Retained on ith seive)
i 1
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( D30 ) 2
Cc
D10 D60
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Example #1 Example #1
Using the following sieve results, find (a) the percent finer of
each sieve size and plot the grain size distribution, (b) D10,
D30 and D60 from the distribution curve, (c)the uniformity
coefficient, Cu and the coefficient of graduation Cc.
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Example #1 Example #2
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The diameter of the finer particle sizes, in particular The average diameter of a soil is given as D50.
D15, has been used to develop criteria for soil filters.
Terzaghi and Peck (1948), for example, proposed the Particle size analysis has many uses in engineering.
following set of criteria for an effective soil filter:
D15( F ) They are used to select aggregates for concrete, soils
4 ( to prevent filter soil from being washed away)
D85( BS ) for the construction of dams and highways, soils as
filters, and material for grouting and chemical
D15 ( F )
4 ( to ensure a higher rate of flow water) injection.
D15( BS )
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PI
A
Clay fraction (%)
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Tests …Tests
Liquid Limit
The liquid limit is determined from an apparatus that
consists of a semispherical brass cup that is
repeatedly dropped onto a hard rubber base from a
height of 10 mm by a cam-operated mechanism.
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36
35
w (%)
34
33
32
31
30
0 5 10 15 20 25 30 35 40
No of blows
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