Shear Box Test on Sand - Soil Mechanics Lab Experiment

This document presents a solved assignment focusing on the shear box test conducted on sand samples to determine their ultimate shear strength parameters. The experiment involves testing both loose and dense sand specimens under varying normal loads (5, 25, and 50 kg). The procedure includes measuring the dimensions and mass of the shear box, compacting the sand for dense specimens, and gently pouring for loose specimens. Horizontal displacement and corresponding proving ring and vertical dial gauge readings are recorded. The data sheets provide detailed measurements, and calculations for normal and shear stress are presented. Graphs are included to visualize the relationship between shear stress and horizontal displacement. Considerations and assumptions related to the shear box test, such as the soil failing along a predetermined plane and the influence of void ratio, are discussed. The document concludes with references to relevant resources and websites. Desklib provides access to this and other solved assignments, offering valuable study resources for students.

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Soil Mechanics: Shear box test
First Name MI Last Name
Institution

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1. SHEAR BOX EXPERIMENT ON SAND
1.1 experimental objectives
Determination of ultimate strength parameters of sand soil sample by use of shear box
test.
1.2 Background information
Under varied test configuration of forces, the failure of soil sample is studied on the
horizontal plane of the shear box apparatus. The sample under test is subjected to
constant vertical stress as horizontal displacement happens on part half of the shear
box. The noted horizontal displacements and shear forces is dependent on the density
of the sample under test hence the relationship established at the completion of the
experiment. For instance, if the test sample is originally dense and low normal stress,
resistance due to shear increases to maximum and eventually falls to the ultimate
point. This is manifested by increase in sample volume which as a result has an effect
on void ratio between test samples particles.
1.3 Procedure
Tests will be conducted in six specimens, three on loose specimens and another three
at dense specimens at normal loads of 5, 25, and 50 kg in each case. The test
procedure is as follows;
1. The internal dimensions and mass of empty shear box is measured.
2. For initially dense specimen, 25 blows of the provided hammer to compact the
specimen after placement on the shear box. The depth of the compacted sand
measured and sand volume calculated. Cap the specimen and weigh the box and
contents and density of compacted dense sand determined.
3. For initially loose specimen, upon even and gentle pouring of the sand the surface
is levelled and depth taken. To avoid compaction, no instance of vibration is not
allowed. Cap the specimen and weigh the box and contents and density of loose
sand determined.
4. Normal loads applied after transfer of shear box to the loading frame, lower and
upper bolts on the shear box are removed.
5. Engage the shear box clutch and switch on the motor hence, specimens shearing
begins.

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6. For every horizontal displacement of 0.25 mm, record the proving ring and
vertical dial gauge reading. Proceed with the test until cumulative displacement of
6 mm is attained.
7. For different normal loads, steps 2 to 6 to repeated.
1.4 completed data sheets
1.4.1 SHEAR BOX -DATASHEET 10
1.4.1.1 Sample: dense sample
Test condition
Dimension of box (mm*mm) = 60.00 by 60.00
Area of sample in sq.mm= 3600
Proving ring No.
Calibration constant (N/ div) = 3.1808
Test No. 1 2 3
Normal
load Kg
5 kg 25 kg 50 kg
Density of
sample(t/
cubic m)
0.005 0.017 0.039
Horizontal
displacem
ent in mm
Prov.
Ring
readin
g
divisi
on
Vertical
displacem
ent
mm
Prov.
Ring
readin
g
divisi
on
Vertical
displacem
ent
mm
Prov.
Ring
readin
g
divisi
on
Vertical
displacem
ent
mm
0.00 0.0 0 0.0 0 0.0 0
0.25 5.0 35 18.0 31 75.0 3
0.50 5.0 65 21.0 67 95.0 24
0.75 5.0 95 22.0 99 101.0 56
1.00 4.0 124 21.0 127 101.0 66

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1.25 4.0 140 21.0 153 100.0 115
1.50 3.5 170 19.0 175 98.0 145
1.75 3.0 180 17.5 194 95.0 168
2.00 3.0 200 16.0 213 91.0 188
2.25 2.5 215 15.0 228 88.0 206
2.50 2.5 230 13.0 245 85.0 224
2.75 2.0 240 11.0 255 82.0 237
3.00 2.0 250 9.5 262 80.0 248
3.25 1.5 260 9.0 266 78.0 251
3.50 1.5 268 7.0 272 77.0 252
3.75 1.5 273 6.0 274 76.0 260
4.00 1.5 278 5.0 274 75.0 269
4.25 1.0 285 4.5 274 75.0 276
4.50 1.0 288 5.0 272 73.0 279
4.75 1.0 293 4.0 269 75.0 279
5.00 1.0 296 4.0 268 75.0 279
5.25 1.0 297 4.5 262 77.0 280
5.50 0.5 299 3.0 260 79.0 281
5.75 0.5 300 3.5 255 78.0 282
6.00 0.5 300 4.0 253 79.0 282
Depth of shear box Before compaction After compaction
32 mm For 5 kg
load
3.0 mm
32 mm 25 kg
load
4.0 mm
32 mm 50 kg
load
3.5 mm

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Weight of empty shear
box in grams
Weight of shear box
with sand
Weight of sand
1070.18 For 5 kg 1252.96 182.78
1070.18 For 25 kg 1262.23 192.05
1070.18 For 50 kg 1253.18 183.0
1.4.2 SHEAR BOX -DATASHEET 10
1.4.2.1 Sample: Loose sample
Test condition
Dimension of box (mm*mm) = 60.00 by 60.00
Area of sample in sq.mm= 3600
Proving ring No.
Calibration constant (N/ div) = 3.1808
Weight of empty shear box= 2155.60 g
Weight of shear box with sand= 2352.95 g
Weight of sand = 2352.95-2155.60= 197.35 g
Test No. 1 2 3
Normal
load
5 kg 25 kg 50 kg
Density of
sample (t/
cubic m)
0.045 0.017 0.382
Horizontal
displacem
ent mm
Prov.
Ring
readin
g
divisi
on
Vertical
displacem
ent
mm
Prov.
Ring
readin
g
divisi
on
Vertical
displacem
ent
mm
Prov.
Ring
readin
g
divisi
on
Vertical
displacem
ent
mm
0.00 0.0 0 0 0 0.0 0
0.25 8.0 0 32.0 1 22.0 0

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0.50 10.0 72 53.0 94 98.0 89
0.75 12.0 55 62.0 85 125.0 77
1.00 14.0 51 70.0 79 147.0 76
1.25 15.0 41 76.0 78 154.0 75
1.50 16.0 35 80.0 78 164.0 75
1.75 17.0 33 86.0 78 175.0 75
2.00 17.5 33 87.0 79 182.0 78
2.25 18.0 33 90.0 80 186.0 88
2.50 18.5 33 90.5 90 185.0 93
2.75 19.0 33 92.0 94 190.0 98
3.00 20.0 33 92.0 98 190.0 110
3.25 20.5 33 91.5 105 191.0 118
3.50 21.0 33 93.0 121 192.0 123
3.75 21.5 33 92.0 123 191.5 131
4.00 21.5 33 92.5 180 194.0 139
4.25 21.5 35 92.0 181 191.5 148
4.50 22.0 35 92.0 139 190.0 157
4.75 22.0 38 91.0 144 190.0 172
5.00 22.0 40 91.0 147 179.0 174
5.25 22.0 48 91.0 148 174.0 180
5.50 22.0 56 92.0 156 174.0 182
5.75 22.5 65 92.0 156 173.0 188
6.00 22.5 70 92.0 160 173.0 190
1.5
1.5.1 Shear box test-Datasheet 11 for dense sand
Normal shear stress in kPa= [ load × g ]
area of shear box
For instance for a load of 5 kg, normal shear stress
σ = [ 5 × 9.81 ]
3600 =0.013625 N
m m2 × 1000=13.625 kPa
Shear stress τ= calibration constant × proving ring dimension

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Test No. 1 2 3
Normal
stress in
kPa σ
13.625 68.125 136.25
Horizonta
l depth in
mm
τ, shear
stress in
kPa
Stress
ratio τ/σ
Τ, shear
stress in
kPa
Stress
ratio τ/σ
Τ, shear
stress in
kPa
Stress
ratio τ/σ
0.00 0 0 0 0 0 0
0.25 15.9 1.17 57.3 0.84 238.6 1.75
0.50 15.9 1.17 66.8 0.98 302.2 2.22
0.75 15.9 1.17 70.0 1.03 321.3 2.36
1.00 12.7 0.93 66.8 0.98 321.3 2.36
1.25 12.7 0.93 66.8 0.98 318.1 2.34
1.50 11.1 0.81 60.43 0.89 311.7 2.29
1.75 9.5 0.70 55.7 0.82 302.2 2.22
2.00 9.5 0.70 50.9 0.75 289.5 2.12
2.25 8.0 0.59 47.7 0.70 279.9 2.05
2.50 8.0 0.59 41.4 0.61 270.4 1.98
2.75 6.4 0.47 35.0 0.51 260.8 1.91
3.00 6.4 0.47 30.2 0.44 254.5 1.87
3.25 4.8 0.35 28.6 0.42 248.1 1.82
3.50 4.8 0.35 22.3 0.33 244.9 1.80
3.75 4.8 0.35 19.1 0.28 241.7 1.77
4.00 4.8 0.35 15.9 0.23 238.6 1.75
4.25 3.2 0.23 14.3 0.21 238.6 1.75
4.50 3.2 0.23 15.9 0.23 232.2 1.70
4.75 3.2 0.23 15.9 0.23 238.6 1.75
5.00 3.2 0.23 12.7 0.19 238.6 1.75
5.25 3.2 0.23 14.3 0.21 244.9 1.80
5.50 1.6 0.12 9.5 0.14 251.3 1.84
5.75 1.6 0.12 11.1 0.16 248.1 182

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6.00 1.6 0012 12.7 0.19 251.3 1.84
1.5.2 Shear box test-Datasheet 11 for loose sand
Test No. 1 2 3
Normal
stress in
kPa σ
13.625 68.125 136.25
Horizonta
l depth in
mm
τ, shear
stress in
kPa
Stress
ratio τ/σ
τ, shear
stress in
kPa
Stress
ratio τ/σ
τ, shear
stress in
kPa
Stress
ratio τ/σ
0.00 0.0 0 0 0 0 0
0.25 25.4 1.86 101.8 1.49 70.0 0.52
0.50 31.8 2.33 168.6 2.74 311.7 2.29
0.75 38.2 2.80 197.1 2.89 397.6 2.92
1.00 44.5 3.27 222.7 3.27 467.6 3.43
1.25 47.7 3.5 241.7 3.55 489.8 3.59
1.50 50.9 3.74 254.5 3.74 521.7 3.83
1.75 54.1 3.97 273.5 4.01 556.6 4.09
2.00 55.7 4.09 276.7 4.06 578.9 4.25
2.25 57.3 4.21 286.3 4.20 591.6 4.34
2.50 58.8 4.32 287.9 4.23 588.4 4.32
2.75 60.4 4.43 292.6 4.30 604.4 4.44
3.00 63.6 4.67 292.6 4.30 604.4 4.44
3.25 65.2 4.79 291.0 4.27 607.5 4.46
3.50 66.8 4.90 295.8 4.34 610.7 4.48
3.75 68.4 5.02 292.6 4.30 609.1 4.47
4.00 68.4 5.02 294.2 4.32 617.1 4.53
4.25 68.4 5.02 292.6 4.30 609.1 4.47
4.50 70.0 5.14 292.6 4.30 604.5 4.44
4.75 70.0 5.14 289.5 4.25 604.5 4.44
5.00 70.0 5.14 289.5 4.25 569.4 4.18

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5.25 70.0 5.14 289.5 4.25 553.5 4.06
5.50 70.0 5.14 292.6 4.30 553.5 4.06
5.75 71.6 5.26 292.6 4.30 550.3 4.04
6.00 71.6 5.26 292.6 4.30 550.3 4.04
1.6 Normal and ultimate shear stress
Normal
stress (kPa0
τult ultimate shear stress
( loose sand ) kPa
τult ultimate shear stress
( dense sand ) kPa
13.625 71.6 15.9
68.125 295.8 70.0
136.25 610.7 321.3
1.7 graphs

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1.8 considerations/ assumptions

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In the shear box test, the example isn't flopping along its weakest plane yet along a foreordained
or actuated plane of failure. Direct shear test is basic and quicker to work. As more slender
examples are utilized in shear box, they encourage drainage of pore water from a soaked
example in less time
The volume change in sandy soil is an unpredictable marvel contingent upon degree, molecule
shape, state and kind of pressing, introduction of chief planes, vital pressure proportion, push
history, size of minor important pressure, sort of contraption, test system, technique for planning
example and so forth. Loose sands extend and dense sands contract in volume on shearing. There
is a void proportion at which either extension compression in volume happens. This void
proportion is called basic void proportion. Extension or constriction can be gathered from the
development of vertical dial check amid shearing.

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References
Accrotechscientific.com. (2018). Soil Test Apparatus - Shear Test Apparatus, Direct Shear Test
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Engineeringcivil.com. (2018). Various Lab Test On Soil. [online] Available at:
https://www.engineeringcivil.com/various-lab-test-on-soil.html [Accessed 6 Oct. 2018].
KISHIMOTO, R. (2013). The Structures of the Shear Layers in Box Shear Test of Soil.
Landslides, 31(1), pp.10-20_1.
Scribd. (2018). Shear Box Lab Report | Density | Strength Of Materials. [online] Available at:
https://www.scribd.com/document/259498355/Shear-Box-Lab-Report [Accessed 6 Oct.
2018].
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Nature.berkeley.edu. (2018). [Online] Available at:
https://nature.berkeley.edu/soilmicro/methods/Soil%20moisture%20content.pdf
[Accessed 5 Oct. 2018].
The Constructor. (2018). Shear Strength of Soil by Direct Shear Test. [online] Available at:
https://theconstructor.org/geotechnical/shear-strength-soil-direct-shear-test/3112/
[Accessed 5 Oct. 2018].