Shear box test

Shear box test

1. Shear box
Tests

2. Introduction
Shear box test is a test to determine the shear strength of soils.
In principle, this test is to determine the failure strength on a
surface that has been set. This apparatus contains a copper
box, horizontally in the middle of the soil samples. Land
gripped the bars of metal, porous discs can be placed on his
back if necessary to allow the sample drain. Usually the size
of the sample size of 60 mm x 60 mm. To test granular
materials such as gravel or rocky clay, the larger box is
needed, which is 300mm x 300 mm. However, sometimes a
larger dimension is used also




box in
external box
skru motorized
loading
hanger load
load
pressure plate
dial gauge
Yoke

loading screw
motor

3. OBJECTIVE

Student should be able to:
 describes the shear box tests and determine the soil shear
strength parameters

4. Theory
The strength of a soil depends of its resistance to shearing stresses. It
is made up of basically the
Components;
1. Frictional – due to friction between individual particles.
2. Cohesive - due to adhesion between the soil particles
The two components are combined in Coulomb’s shear strength
equation,
τf = c + σf tan ø
Where τf = shearing resistance of soil at failure
c = apparent cohesion of soil
σf = total normal stress on failure plane
ø = angle of shearing resistance of soil (angle of internal friction)

This equation can also be written in terms of effective stresses.

1. Assemble the shear box
2. Compact the soil sample in mould after bringing it to optimum
moisture condition
3. Carefully transfer the sample into shear box
τf = c’ + σ’f tan ø’
Where c’ = apparent cohesion of soil in terms of effective stresses
σ'f = effective normal stress on failure plane
ø’ = angle of shearing resistance of soil in terms of effective stresses
σ'f = σf – uf
uf = pore water pressure on failure plane

5. Equipment


Shear Box Apparatus with ADU


Dial gauge.


Load


Pan Balance – sensitive to 0.1 gram

6. DATA AND ANALYSIS
DEFORMATION PROVING RING SHEAR
STRESS
STRAIN
DIAL ΔL (mm) x
0.01
DIAL LOAD, P
(kN)
P/A
(kN/m
2
)
ε = ΔL/LO
0 0 0 0 0 0
50 0.5 9 0.01845 5.13 8.33
100 1.0 14 0.0287 7.97

16.67
150 1.5 18 0.0369 10.25 25.00
200 2.0 21 0.04305 11.96 33.33
250 2.5 25 0.05125 14.34 41.67
300 3.0 28 0.0574 15.94 50.00
350 3.5 31 0.06355 17.65 58.33
400 4.0 31 0.06355 17.65 66.67
450 4.5 32 0.0656 18.20 75.00
500 5.0 35 0.07175 19.93 83.33
550 5.5 37 0.07585 21.07 91.67
600 6.0 39 0.07995 22.21 100.00
650 6.5 41 0.08405 23.35 108.33
700 7.0 42 0.0861 23.92 116.67
750 7.5 45 0.09225 25.63 125.00
800 8.0 46 0.0943 26.20 133.33
850 8.5 47 0.09635 26.76 141.67
900 9.0 48 0.0984 27.30 150.00
950 9.5 48 0.0984 27.30 158.33
1000 10.0 49 0.10045 27.90 166.67
1050 10.5 49 0.10045 27.90 175.00
1100 11.0 49 0.10045 27.90 183.33
1150 11.5 49 0.10045 27.90 191.67
1200 12.0 49 0.10045 27.90 200.00
1250 12.5 49 0.10045 27.90 208.33

7. DEFORMATION PROVING RING SHEAR
STRESS
STRAIN
DIAL ΔL (mm) x
0.01
DIAL LOAD, P
(kN)
P/A
(kN/m
2
)
ε = ΔL/LO
0 0 0 0 0 0
50 0.5 5 0.01025 2.85

8.33
100 1.0 13 0.02665 7.40

16.67
150 1.5 15 0.03075 8.54 25.00
200 2.0 16 0.0328 9.11 33.33
250 2.5 23 0.04715 13.10 41.67
300 3.0 28 0.0574 15.94 50.00
350 3.5 33 0.06765 18.79 58.33
400 4.0 37 0.07585 21.07 66.67
450 4.5 40 0.082 22.78 75.00
500 5.0 43 0.08815 24.49 83.33
550 5.5 46 0.0943 26.19 91.67
600 6.0 48 0.0984 27.33 100.00
650 6.5 50 0.1025 28.47 108.33
700 7.0 52 0.1066 29.61 116.67
750 7.5 54 0.1107 30.75 125.00
800 8.0 55 0.11275 31.32 133.33
850 8.5 56 0.1148 31.89 141.67
900 9.0 57 0.11685 32.46 150.00
950 9.5 58 0.1189 33.03 158.33
1000 10.0 58 0.1189 33.03 166.67
1050 10.5 58 0.1189 33.03 175.00
1100 11.0 58 0.1189 33.03 183.33

8. DEFORMATION PROVING RING SHEAR
STRESS
STRAIN
DIAL ΔL (mm) x
0.01
DIAL LOAD, P
(kN)
P/A
(kN/m
2
)
ε = ΔL/LO
0 0 0 0 0 0
50 0.5 8 0.0164 4.56 8.33
100 1.0 12 0.0246 6.83 16.67
150 1.5 18 0.0369 10.25 25.00
200 2.0 25 0.05125 14.24 33.33
250 2.5 31 0.06355 17.65 41.67
300 3.0 36 0.0738 20.50 50.00
350 3.5 41 0.08405 23.35 58.33
400 4.0 46 0.0943 26.19 66.67
450 4.5 50 0.1025 28.47 75.00
500 5.0 54 0.1107 30.75 83.33
550 5.5 58 0.1189 33.03 91.67
600 6.0 60 0.123 34.17 100.00
650 6.5 65 0.13325 37.01 108.33
700 7.0 67 0.13735 38.15 116.67
750 7.5 69 0.14145 39.29 125.00
800 8.0 71 0.14555 40.43 133.33
850 8.5 72 0.1476 41.00 141.67
900 9.0 75 0.15375 42.71 150.00
950 9.5 76 0.1558 43.28 158.33
1000 10.0 78 0.1599 44.42 166.67
1050 10.5 78 0.1599 44.42 175.00
1100 11.0 79 0.16195 45.00 183.33
1150 11.5 80 0.164 45.56 191.67
1200 12.0 80 0.164 45.56 200.00
1250 12.5 80 0.164 45.56 208.33
1300 13.0 80 0.164 45.56 216.67

9. Table Maximum Value For Load
Load, P (kg) 5 10 15
Load, σ (kN)
(normal stress)
5 x 10
1000
= 0.05 kN
10 x 10
1000
= 0.1 kN
15 x 10
1000
= 0.15 kN
Maximum Shear
Stress, Ґ
28.00 33.00 46.00

У = mx + C
Ґ = tan θσ + C

10. CONCLUTION

The conclusion is, shear box test is an example test used to
determine the shear strength of soils. In principle, this test is
to determine the failure strength on a surface that has been set.
However, the importance of shear box test is to determine the
shear strength of soil on the surface and it can be test by other
test that can determine the failure strength,

11. Reference

1. Donald Mcglinchey, , Characterisation of bulk solids, 2005, CRC
Press DT Afrika.
2. Mazlan Mohammad Abdul Hamid, Standard aggregate sieve
analysis TEST, ASTM International - Standards Worldwide, (July
2008) ASTM C136-06, retrived from http://www.astm.org/
3. Norliza Muhammad, concrete laboratory,(2006). Gradation Test.
(2007), NorlizaMuhammad,FajarBaktiSdn. Bhd.