core cuter test
OBJECT
To determine the field density of soil
by core cutter method
REFERENCE
IS-2720-Part-29-Determination of dry
density of soil in place by the core-cutter method
APPARATUS
1.
Cylindrical
core cutter
2.
Steel
rammer
3.
Steel
dolly
4.
Balance
5.
Steel
rule
6.
Spade
or pickaxe
7.
Straight
edge
8.
Knife
Fig:-Showing Core
cutter, Dolly & Rammer
PROCEDURE
1.
Measure
the height (h) and internal diameter (d) of the core cutter and apply grease to
the inside of the core cutter
2.
Weigh
the empty core cutter (W1)
3.
Clean
and level the place where density is to be determined.
4.
Drive
the core cutter, with a steel dolly on its top, into the soil to its full depth
with the help of a steel rammer.
5.
Excavate
the soil around the cutter with a crow bar and gently lift the cutter without
disturbing the soil in it.
6.
Trim
the top and bottom surfaces of the sample and clean the outside surface of the
cutter.
7.
Weigh
the core cutter with soil (W2)
8.
Remove
the soil from the core cutter, using a sample ejector and take representative
soil sample from it to determine the moisture content.
Table:-Observations and Calculations of core
cutter test
S.No.
|
Details of
Core
|
Samples
|
1
|
|||
|
|
|||||
Chainage
|
|
|||||
Location
|
|
|||||
1
|
|
Physical
properties
|
|
|
|
|
|
A
|
Weight
|
Kg.
|
W
|
|
1.949
|
|
B
|
Dia
|
Mm
|
D
|
|
88
|
|
C
|
Height of finished core
|
Mm
|
H
|
|
138
|
|
D
|
Height / dia ratio
|
-
|
N
|
=h/D
|
1.57
|
|
E
|
Volume of core
|
M3
|
V
|
=(π/4)*d2
|
0.0008
|
|
F
|
Density of core
|
Kh/m3
|
ϒ
|
=W/V
|
2322.08
|
2
|
|
Strength
properties
|
|
|
|
|
|
A
|
Load
|
KN
|
P
|
|
158
|
|
B
|
Area
|
Mm2
|
A
|
|
6082.12
|
|
C
|
Cylindrical strength
|
n/mm2
|
ϸcylin
|
=P/A
|
25.98
|
3
|
|
Correction
Factors
|
|
|
|
|
|
A
|
For shape & height of c
|
-
|
F
|
|
1.1875
|
|
|
|
|
|
|
|
4
|
|
Calculations
|
|
|
|
|
|
A
|
Equivalent cube strength
|
N/mm2
|
ϸcube
|
=f*pcylin
|
30.85
|
correction factor = 0.78+0.11*H/D
= 0.78+0.11*138/88
= 0.9527
cubical shape factor = 1.25
equivalent cube strength =
25.98*1.25*.9527
=
30.85 N/mm2
RESULT
equivalent cube strength = 30.85 N/mm2
PRECAUTIONS
1.
Core
cutter method of determining the field density of soil is only suitable for
fine grained soil (Silts and clay). This is because collection of undisturbed
soil sample from a coarse grained soil is difficult and hence the field
properties, including unit weight, cannot be maintained in a core sample
2.
Core
cutter should be driven into the ground till the steel dolly penetrates into
the ground half way only so as to avoid compaction of the soil in the core.
3.
Before
lifting the core cutter, soil around the cutter should be removed to minimize
the disturbances.
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