To determine the range of particles sizes and a known mass of soil classification in the laboratory.
Theory
Classification of a known soil sample in relation to its particle distribution is done using sieve analysis. The experiment in the soil classification will be demonstrated using the test method of BS1377-2: 1990 (WES 1953).
Apparatus
Sieve Shaker
Figure 1.0
Bench Scale
Figure 1.1
Procedure
14 sieves ranging from size 14mm to 63 μm were used stacked in a descending order. They were then placed in two piles of 7 sieves with a receiver at the bottom and a lid at the top since the agitator could not accommodate all sieves at the same time. A known mass of soil sample was then placed in the prepared sieves which were then placed on the agitator in a pile with closed lid and locked to the agitator. The lid prevented dust during shaking and loss of particles during agitation which lasted 2 minutes.
Using scale, the agitated sample was measured in an empty plate on the scale. The soil sample was then placed in the empty plates from the sieve in a descending order and a brush was used to remove stuck particles. The percentage passing could then be determined by the mass of soil retained on each sieve and the results plotted on a graph.
Results
Percentage Retained
Cumulative percentage retained
Percentage passing
Location
Job Ref
Borehole/Pit no.
Soil description
Sample no.
Test method
BS1377-2: 1990
Depth
m
Initial dry mass m1
2000.0 g
Date
26/01/2017
BS test sieve (mm)
Mass retained (g)
Percentage retained (m/m1)
Cumulative percentage passing
Percentage passing
14
0
0
0
100
10
118.3
5.92
5.92
94.08
6.3
818.5
40.93
46.84
53.16
5
69.47
3.47
50.31
49.69
3.35
0
0
50.31
49.69
2
74.7
3.74
54.05
45.95
1.18
48.4
2.42
56.47
43.53
0.6
39.5
1.98
58.44
41.56
0.425
28.5
1.43
59.87
40.13
0.3
565.3
28.27
88.13
11.87
0.212
128.5
6.43
94.56
5.44
0.15
89.11
4.46
99.01
0.99
0.063
17.4
0.87
99.88
0.12
0
0.65
0.03
99.92
0.08
Discussion
Particle distribution can be distinguished from the grading results for the soil sample.
The coefficient is less than 4 and therefore it can be concluded that the soil is sand which is well graded and with little silt.
Determination of Particle-Specific Gravity
Objectives
To determine the specific gravity of a soil sample
Theory
Specific gravity is a dimensionless unit considered as the density of a substance to the density of water ratio at a specific temperature (The Engineering ToolBox). From the experiment, the specific gravity of fine-grained soil can be determined using density bottle method.
Apparatus
Empty gas jar
Gas jar lid
Bench scale
Water
Soil sample
Procedure
Mass of gas jar was determined with its cover and then dried soil placed in the gas jar, covered and mass determined. Water was then added to a gas jar that contains soil and its mass determined. Finally, the gas jar was emptied, filled with water only and its mass recorded.
Results
The equation for specific gravity;
Mass of soil particles:
Volume of soil particles:
Specific gravity of a granular soil:
Mass of gas jar + cover
(m1)
874.6(g)
Mass of gas jar +cover + soil
(m2)
1083.9(g)
Mass of gas jar + cover + soil + water
(m3)
2348.8(g)
Mass of gas jar + cover + water
(m4)
2218.6(g)
Mass of soil particles
(m2 – m1)
209.3(g)
Volume of soil particles
(m4-m1) – (m3 –m2)
79.1(cm3)
2.646
Discussion and Conclusion
The results illustrate that soil sample is organic clay. This is because of the specific gravity of organic clay ranges from 2.58 to 2.65 and the value found (2.646) lies in between the ranges signifying the success of the experiment.
References
Bowles, J. E. (1992). Engineering Properties of Soils and Their Measurement, 4th edition. Singapore: McGraw-Hill Book Co-Singapore.
Haynes, J. (2014-15). Structures 1 Module Handbook. Salford: Jonathan Haynes.
The Engineering ToolBox. (n.d.) Density, specific weight and specific gravity. [Online]. Available at:
WES. (1953). The United Soil Classification System. Vicksburg, MS: U. S. Army Engineer Waterways Experiment Station.
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