Field control of compaction and compaction Equipment

1. Field control of compaction and
compaction Equipment
Guided By
Prof. Dr. A.K. Chaudhary Sir
NIT, Jamshedpur
Submitted By
Aishwarya Gupta
Roll No.-
2020PGCEGE03
Mtech -2nd Semester
GeotechnicalEngineering
Department of Civil Engineering

2. Field Comapaction Control
It is very important to undersatand the factor
affecting compaction in field and to estimate
the co-relation between laboratory and field
test
Field Compaction Control Depends on
a) Placement water content
b) Type of Equipment for compation
c) Type of compaction based on soil type &
degree of compaction desired

3. (a) Placement Water Content:
The water content to be used for
compacting the soil in the field is
known as placement water content.
Usually, a placement water content of
±2% of OMC obtained from relevant
laboratory compaction test is adopted.

4.  For highway embankments of cohesive soils
to achieve higher shear strength and lower
compressibility we compact it Dry Of
Optimum.
 outer shells of earth dams are compacted at 1
to 2.5% less then OMC (dry of optimum) to
reduce pore water pressure developement
 the core of an earth dam is compacted at
more than the OMC (wet of optimum) to
reduce the permeability and achieve safty
against cracking

5.  The basic principle of Proctor’s needle
method is to determine the water content
and Dry Density of compacted soil
 based on the resistance offered by the
compacted soil to the penetration of
Proctor’s needle.
 The needle can be pushed into the
compacted soil by pressing the loading
plunger.
 The needle shank has graduations to read
the penetration of the needle into the
compacted soil and this shows the
resistance offered by the compacted soil
to the penetration of the needle.
Proctor’s Needle Method

6.  Proctor needle test is
used for quick
evaluation of
maximum soil density
in the field.
 Standard Compaction
curves showing
moisture contents
versus densities are
drawn in laboratory
using standard
compaction method
and penetration of
the proctor needles

7. Relative Compaction (R.C.)
100%
R.C.
Typical required R.C. = 90% ~ 95%
 MDD obtained from laboratory IS light or heavy
compaction Test
 By deciding relative compaction and maximum dry
density in laboratory we can calculate the In situ dry
density of the fill.
In situ dry density of
compacted fill
Max. Dry density from
lab.comapaction test

8. 8
Measurement of Field Compaction
A few methods are asfollows:
Destructive methods
•Core cutting method
•Sand replacement method
•Volumenometer method
•Rubber-balloon method
•Proctor-needle method
Non- destructive methods
• Nuclear gauge method
• Impact Tester

9. 9
Equipment For Field Compaction
Ordinary compaction in the field is done by
rollers. Of the several types of roller used,
the most common are
Smooth-wheelrollers(or smoothdrum
rollers)
pneumatic rubber-tiredrollers
Sheepfootrollers
Vibratoryrollers

10. Smooth-wheelrollers(or smooth drumrollers)
 This type of
roller incorporates a
large steel drum at the
front and one at the
rear.
 It can be used for
compaction of both type of
soil; cohesive and cohesion
less soil.
It produce contact
pressure of 400 – 500
kN/m2 .
 They do not
uniform unit
produce a
weight of
compaction when used on
thick layers.
Fig. Smooth WheelRoller

11. Pneumatic rubber-tired rollers
• Pneumatic rubber-tired
rollers consist of a heavily
loaded wagon with several
rows of tires, produce a
combination of
and kneading
pressure
action
during compaction.
• Pneumatic rollers, which
can be used for sandy and
clayey soil compaction.
• The contact pressure under
the tires may range up to
600- 700 kN/m2.
• They provide 70–80% coverage
under the wheels.
Fig.Pneumaticrubber-tired rollers

12. Sheep foot rollers
• Sheepsfoot rollers also
known as a tamping
roller. Steel drum of
sheepsfoot roller consist
of many rectangular
shaped boots of equal
sizes fixed in hexagonal
pattern.
• These rollers are most
effective in compacting
cohesivesoils.
• The contact pressure under the
projections may range from 1500 to
7500 kN/m2.
• During compaction in the field, the
initial passes compact the lower
portion of a lift. Later, the middle
andtopof thelift are compacted.
Fig.Sheep footrollers
12

13. Vibratory rollers
 In vibratory
rollers vibration is
produced by weights
placed
eccentrically on a rotating
shaft in such a manner that
the forces produced by the
weights are
in a vertical
rotating
essentially
direction.
 Vibratory
efficient in
rollers are
compacting
granular soils.
 The weights of vibratory
rollers range from 120 to
300 kN.
Fig.Vibratoryrollers