ce206-compaction of soils

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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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 9

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7 " .2 /

7 7 3 $ ); 5,


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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

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$

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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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'() *+ ,-.,/

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B

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!

Holtz and Kovacs, 1981

010

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%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)


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



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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

ce206-compaction of soils

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