DETERMINATION OF PARTICLE
SIZE DISTRIBUTION OF A GIVEN SOIL SAMPLE
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1. To conduct the sieve analysis for the
given sample and plot the grading curves.
2. To determine the coefficient of
uniformity (Cu).
3. To determine the coefficient of
curvature (Cc).
4. To determine the effective size (D10).
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1. Test sieve to British standard (BS
410)/.
2. Mechanical sieve shaker.
3. Balances
4. Riffle box.
5. Standard dry oven 105 – 110.
6. Sieve brushes
7. Metal trays.
8. Rubber pestle and mortar.
9. Scoop and miscellaneous small tools.
10.Sieve analysis worksheet.
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The appropriateness of a soil for a specific use in development is frequently reliant on the dispersion of grain sizes in the dirt mass. There are two test used to examine the molecule measure conveyance in a dirt. One of these strategies is the strainer investigation. The test is the key prerequisite for distinguishing proof and for determination consistence testing for coarse soils.
The outcome from the sieve analysis of the soil when plotted on a semi-log diagram with molecule width or sifter measure as the abscissa with logarithmic pivot and the rate going as the ordinate gives a reasonable thought regarding the molecule estimate dissemination. From the assistance of the bend, D10 and D60 are resolved. The D10 is the distance across of the dirt beneath which 10% of the dirt particles lie (otherwise called the powerful size). The proportion of D10 and D60 gives theconsistency coefficient (Cu) which in turns is a measure of the molecule estimate go.
The particle size distribution (gradation) refers to the proportions by the mass of aggregate particle distributed in specified particle size ranges. In the sieve analysis,delegate test of the total is gone through a progression of strainer and the weight held in each strainer (communicated as the level of the example weight) is contrasted and as far as possible indicated. Notice that the majority of the fine total goes through s 4.75mmm strainer measure while a huge level of the coarse totals are retrained on a 4.75mm sifter total size and degree are frequently indicated by posting strainer sizes and a scope of " rate going" for each size.
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Choice OF SAMPLE: The soil sample to be utilized for the test is gotten from the first example by riffling, or by sub-division utilizing the come and quarter technique.
2.
PREPARATION OF
SAMPLE: The specimen
3.
SELECTION AND
ASSEMBLY OF SIEVES: The strainers to be utilized are chosen to suit the span of test and sort of material. Picking eight sifters and a container. They were organized in diving orders starting from the greatest sifter to the littlest strainer.
4.
SIEVING: the dried soil test was set in the highest strainer and shaken for quite some time for all particles littler than every gap size to go through.
5.
WEIGHING: The material held on each strainer is moved thus of the dish of a reasonable adjust on every wa exchanged to the skillet of an appropriate adjust, on to a measured compartment, all particles stopped to the opening of the sifter was painstakingly expelled with strainer brush. The majority held (m1, m2… ) was recorded against the strainer opening size on the molecule measure test work sheet.
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Sieve Analysis
Date Tested: 12th may 2016
Tested By: Group 6
Visual Classification of Soil: Gravel
Weight of Container: 55gm
Wt. Container + Dry Soil: 510gm
Wt.
of Dry Sample: 455gm
SIEVE SIZE
(mm)
|
WEIGHT OF
SIEVE (g)
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WEIGHT OF
SAMPLE + SIEVE (g)
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WEIGHT OF
SAMPLE RETAINED(g)
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% WEIGHT
RETAINED
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% CUMMULATIVE
WEIGHT RETAINED
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% PASSING
|
16
|
570
|
588
|
18
|
4.0
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4.0
|
96
|
8
|
551
|
678
|
127
|
27.9
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31.9
|
68.1
|
4
|
474
|
749
|
275
|
60.4
|
92.3
|
7.7
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2.36
|
518
|
534
|
16
|
3.5
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95.8
|
4.2
|
1
|
489
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490
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1
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0.2
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96.0
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4.0
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0.5
|
322
|
326
|
4
|
0.9
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96.9
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3.1
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0.3
|
468
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469
|
1
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0.2
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97.1
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2.9
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0.25
|
453
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453
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0
|
0
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97.1
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2.9
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PAN
|
400
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413
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13
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2.9
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100
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0
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Σ 455 100
From
Grain Size Distribution Curve:
% Gravel= 96
D10=4.375 mm
% Sand= 1.9 D30= 6.000mm
% Fines= 2.1 D60= 7.750mm
Cu=
1.771 CC= 1.062
Coefficient
of uniformity (Cu) = D60 = 7.750 = 1.771
D10 4.375 
Coefficient
of Curvature, (CC) = (D30) ^2 = 6.000^2 = 36 =1.062
D10 x D60 4.375 x 7.750 33.906
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Ø Zero error was avoided by setting the weighing balance to zero.
Ø Error due to parallax was avoided when taking
the reading of the weight on the weighing balance.
Ø The sieve was cleaned and dry before filling
it with soil sample.
Ø The sieves were brushed properly for the
essence of accuracy.
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Some of the errors that may affect the outcome of the experimental
result include:
o
Human error:
-
Error could probably occur if the
sample is not completely dry.
-
Error due to parallax when taking
readings.
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Error due to the imperfection of the
experimenter.
o
Instrumental error:
-
Error could arise due to the
instability of the measurements taking by the weighing balance; the difference
noted was 1g.
o
Random error:
-
Environmental air effect.
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Laboratory experimental condition.
v From the value of CU and CC obtained from the graph it could be concluded that the soil sample is poorly graded.
v From
the graph it was found that the sample used for the particle size distribution
was a very gravel sand sample as it
contains 96% of gravel by proportion
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