Determination of mechanical properties of soil by Vane Shear Test Direct shear Test Triaxial Compression Test

1. Submitted To:
Submitted by: Dr. Zainal Abedin
1705082 Professor
1705083 Dept. of Farm Structure &
1705089
Environment
1705093 Engineering
1605007
WELCOME TO OUR
PRSENTATION

2. Content:
Objective
Theory
Apparatus
Methodology
Data Table
Result
Discussion

3. Name OF The Experiment:
Determination of mechanical properties of
soil by
1. Vane Shear Test
2. Direct shear Test
3. Triaxial Compression Test
Vane Shear Direct Shear

4. Determination of soil Mechanical
properties of soils by Hand vane Tester
Objectives:
 To determine the shear strength of soil .
 To determine undrained shear strength .
 To determine soil sensitivity .
Fig. : Hand Vane
Shear

5. Theory:
The vane shear means of assessing the un-
drained shear strength shear strength of a
cohesive soil . a torque is applied , the soil is
sheared along a cylindrical surface . the torque
required to shear the cylinder of the soil is
measured by means of a spring balance . the
un-drained shear strength τ is determined from
the following equation:
Where
T=Torque applied
H = Height of vane
D = diameter of soil cylinder sheared.










62
3
2 DD
H
T


6. Apparatus Required:
1.Hand Vane Tester with accessories .
2. Shovel .
3. Spatula etc
Hand shov

7. Methodology:
1. At first we joint the vane with dial gauge by
screwing.
2. Then we made the gauge at zero.
3. The vegetation and loose surface soil in the
test site was cleaned by using spade or shovel.
The flat is surfaced.
4. The vane is put on flat soil surface and pushed
it down to penetrate into soil up to vane top.
5.The vane was rotated by holding the top
gauge at rate of 6 o per minutes. The torque
was acted on the specimen indicated by a
pointer fixed to the spring. The torque was
continued till the soil fails,the dial reading was
stopped to increase.

8. Methodology (cont……)
6. The dial reading was recorded. That reading
was the shear strength of soil.
7. The procedure was repeated for 10 times
reading of the soil and the reading was
averaged.
Field procedure
Vane Shear

9. Observation:
Height of the vane , H=40mm=4cm
Dia. Of soil cylinder sheared , D=
19mm=1.9cm
Data Table:
Observ
a- tions
1 2 3 4 5 6
Shear
Strengt
h , τ
1 1.1
4
1.2
7
1.33 1.4
1
1.5
)/(
2
cmkg

10. Calculation:
Average=
= 125
Result:
The shear strength of soil by Hand
Shear Test was 125
Comments:
So this was stiff soil.
cmKg
2
/275.1
6
5.141.133.127.114.11


mKN
2
/
mKN
2
/

11. Determination of soil mechanical
properties by Direct Shear Test
Objective :
To obtain the parameters of shear
strength(C, ) for a cohesion less
sample .
Theory :
The soil mass leads to failure with continuous
shear deformation induced by the externally
applied forces. The resistance to deformation
for continuous shear displacement of soil
particles is called the shear stress and its
maximum value at which the soil collapses is
called the shear strength .


12. Theory (cont…)
Coulomb (1776) proposed the shear stress
as a linear function of the normal stress acting
on a failure plane by the following relation.
Where
C =Cohesion of soil
=Internal friction angle of the soil
=Shear stress
=Normal stress
 tan C




13. Apparatus Required:
1.Shear box
2. Base plate
3. Grid plate
4. Loading pad
5. Loading frame
6. Proving ring.
7. Dial gauge
8. Balance
9. Spatula
10. Water bottle
11. Measuring cylinder
13. Direct shear testing machine etc.
Shear Box
Direct Shear testing
machine

14. Methodology:
1. Measures the internal dimensions of shear box. Also
determine the average thickness of the grid plates.
2. Fix the upper part of the box to the lower part using the
locking screws. Attach the base plate to the lower part.
3. Place the grid plate in the shear box keeping the serrations of
the grid at right angles to the direction of shear. Place a
porous stone over the grid plate.
4. Weight the shear box with base plate, grid plate and porous
stone.
5. Place the soil specimen in the box. Tamp it directly in the
shear box at the required density. When the soil in the top half
of the shear box is filled up to 10 to 15 mm depth,
6. Weight the box with the soil specimen.
7. Place the box inside the box container , and fix the loading
pad on the box . Mount the box container on the loading

15. Methodology (cont…)
8. Bring the upper half of the box in contact with the
proving ring. Check the contact by giving a slight
movement.
9. Fill the container with water if the soil is to be
saturated; otherwise omit this step.
10. Mount the loading yoke on the ball placed on the
loading pad.
11. Mount one dial gauge on the loading yoke to
record the vertical displacement and another dial
gauge on the container to record the horizontal
displacement.
12. Place the weights on the loading yoke to apply a
normal stress. Allow the sample to consolidate

16. 13. Remove locking screws. Using the spacing screws,
raise the upper part slightly above the
lower part such that the gap is slightly larger than the
maximum particle size. Remove the spacing screws.
14. Adjust the entire dial gauge to read zero. The proving
ring should also read zero.
15. Apply the horizontal shear load at a constant rate of
strain of 0.2 mm/minute
Methodology (cont…)
16. Record readings of the proving ring, the vertical
displacement dial gauge and the horizontal
displacement dial gauge at regular time intervals. Take
the first few readings at closer intervals.
17. Continue the test till the specimen fails.

17. Methodology (cont…)
18. At the end of the test, remove the specimens
from the box and take a representative sample for
the water content determination.
19. Repeat the test on identical specimens under
the normal stresses with double loads.
Procedure of
test

18. Data Sheet:
Area of the shear box, A = 60 x 60 mm 2
Depth, d = 40 mm
Volume=
Table:
SI
N
o
Observation &
calculation 1 2 3 4
1 Weight of empty shear
box,W1
2 Weight of shear box+ soil,W2
3 Bulk density,
4 Normal Load,
v
ww
b
12


Qn
cm
Q
kg
A
n 2
/

19. Table(cont….)
SI
No
Observation& calculation
1 2 3
4
6 Dial reading,
7 Shear load,
8 Shear stress,
9 Water content can No
10 Weight of empty can,W1
11 Weight of can+wet soil,W2
12 Weight of can+oven dry soil,W3
13 Water content,
Dr
 kgDQs
/0826.0
cm
Q
kg
A
s 2
/
ww
www
13
32



Result:….

20. Discussion:
1. As shear test is easy and quick it can be
performed either in laboratory or in the field
directly in the ground .
2. Shear strength and thus types of can be
calculated br both Shear Test method .
Precautions:
1. The revolution of hand vane should be 6
degree per minute .
2. The rotation should be in clock wise .
3. During testing , soil compaction should be
considered.