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7/27/2019 CE206-Compaction of Soils
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Compaction of soilsCompaction of soils
CE 206CE 206 Geotechnical EngineeringGeotechnical Engineering --IIDepartment of Civil Engineering
Indian Institute of Technology Guwahati
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!
"#$
%
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Coarse-grained soils Fine-grained soils
Falling weight and hammersory
Vibratin hammer
Hand-operated vibration plates
Motorized vibratory rollers
Kneading compactors
Static loading and press
Laborat
Rubber-tired equipmentFree-falling weight; dynamic
compaction (low frequency
vibration, 4~10 Hz)
-
Sheepsfoot rollers
Rubber-tired rollers
Fiel
Vibration
(Holtz and Kovacs, 1981; Head, 1992)
Kneading
&
%
%
'
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'' ( )*+,- .)*++/
0 1
3
4 3
2
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(
3 3
% 2
!
Standard Proctor test equipment
Das, 1998
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(.)/
.5/
The first four blowsThe successive blows
.+/ (
.6/
w1,V
Md
t
t
+
== Derive d from the known and w
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7 8
7 9
7 2 5:
7 " .2 /
7 7 3 $ ); 5,
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1 1 %%
9 2
3 3
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3 3 3 3
. "/
? 3 3
3
. A ),, :/
& 2
% ),, :
7/27/2019 CE206-Compaction of Soils
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w
w
wd
G
Sw
S
Sw
S
+
=
+
=
Zero air
void
densityd
(Mg/m3)
ydensityd
(lb/ft3)
Line of
optimums
Modified
d max
s
sd
wGSe
e1
=
+
=
Water content w (%)
D
r
D
Proctor
Standard
Proctor
wopt
B
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%
C%$ 5D5, .( B%%/E)*F+G
C%$5D5, .( B%%%/E)*F+G
H
I -
2-
J
" #
1
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$
!
Holtz and Kovacs, 1981; Das, 1998
$
For a given compactive
,
soil tends to be more
flocculated (random) for
compaction on the dry side
as compared on the wet side.
For a given molding water
content, increasing the
disperse (parallel, oriented)
the soil, especially on thedry side.
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##
(
%
%
2
$# %
From Lambe and
Whitman, 1979
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$ % &
'() *+ ,-.,/
"
B
(
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!
Holtz and Kovacs, 1981
010
$
!"
$
%
K !
1
$?
&
4
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# ! #
&
2
4 #
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$
8
-
L
2 3 !
% #
'22/
%100.C.R filedd
=
Relative compaction or percent compaction
laboratorymaxd
rD2.080.C.R +=
Correlation between relative compaction
(R.C.) and the relative density Dr
It is a statistical result
based on 47 soil
samples.
As Dr = 0, R.C. is 80
Typical required R.C. = 90% ~ 95%
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Methodsa Sand re lacement method
(a)
(b) Balloon
(c) Oil (or water) method
(d) Core cutter method
Calculations
(b)
(c)
Holtz and Kovacs, 1981
Know Ms and Vt
Get d field and w (water content)
Compare d field with d max-laband calculate relative compaction
R.C.
'2/
Check Point Method 100% saturationLine of
optimums
rydensity,d
d max
A
B X
Y(no)
1 point Proctor test
Known compaction
curves A, B, C
Field check point X
(it should be on the
dry side of optimum)
Water content w %
wopt
M
C
Holtz and Kovacs, 1981
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3
2
2 I -
interchangeable needle tips,
ranging from 6.45 to 645 mm2
3
Nuclear density meter
(a) Direct transmission
(a)
(c) Air gap
(b)
PrinciplesDensity
The Gamma radiation is scattered by the soil
particles and the amount of scatter is
ro ortional to the total densit of the material.Holtz and Kovacs, 1981
(c)
The Gamma radiation is typically provided by
the radium or a radioactive isotope of cesium.
Water content
The water content can be determined based on
the neutron scatter by hydrogen atoms. Typical