soil strength improvements using rollers

jjgyokllllllllllllllllllllllllllllllllllllllhhhhhhhhhhhhhhhhhhhhhhhhhh;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;ggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggllllllllllllllllllllllllllllllllllllllllllllpppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppprrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzwwwwwwwwwwwwwwwwwwwwwwwwwwwwwrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrryyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii

1. 1
SHALLOW SURFACE
COMPACTION
DONE BY :
Abdulmajeed alsultan

2. 2
Outline
1.Soil Improvement
2.Compaction
3.Field Compaction Equipment
4.Field Compaction Testing

3. 3
Soil Improvement

4. 4
Methods for Soil Improvement
Ground
Reinforcement
Ground
Improvement
Ground
Treatment
•Stone Columns
•Soil Nails
•Deep Soil Nailing
•Micropiles (Mini-piles)
•Jet Grouting
•Ground Anchors
•Geosynthetics
•Fiber Reinforcement
•Lime Columns
•Vibro-Concrete Column
•Mechanically Stabilized
Earth
•Biotechnical
•Drainage/Surcharge
•Electro-osmosis
•Compaction grouting
•Blasting
•Surface Compaction
•Deep Dynamic
Compaction
•Soil Cement
•Lime Admixtures
•Flyash
•Dewatering
•Heating/Freezing
•Vitrification

5. 5
Compaction

6. 6
Objectives of compaction
Objectives:
(1)Decrease future settlements
(2)Increase shear strength
(3)Decrease permeability
(4)Control swelling and contraction
(5)Increases slope stability of embankments

7. 7
Compaction
What is different between compaction and Consolidation ?
Compaction
Densification of soil by removing air from the voids.
Consolidation
Densification of soil by removing water from the voids.

8. 8
Typesof Compaction
Types of Compaction :
There are four types of compaction effort on soil :
•Vibration
•Impact
•Kneading
•Pressure
SATURATED SOIL NOT COMPACTABLE

9. 9
Field Compaction Equipment

10. 10
Equipment
Smooth-wheel roller (drum)
•100%coverageunderthewheel
•Contactpressureupto400kPa
•Canbeusedonallsoiltypes
exceptforrockysoils
•Compactiveeffort:staticweight

11. 11
Equipment
Pneumatic (or rubber-tired) roller
•80%coverageunderthewheel
•Contactpressureupto700kPa
•7 to 13 wheels are arranged in
two rows.
•Canbeusedforbothgranularand
fine-grainedsoils.
•Compactiveeffort:staticweight
andkneading.

12. 12
Equipment
Sheepsfoot rollers
•8%~12%coverage
•Contactpressureisfrom1400to
7000kPa.
•Compactiveeffort:staticweight
andkneading.

13. 13
Equipment
Sheepsfoot rollers
•Suitablefor:
–finegrainedsoils
–sandsandgravels(with>20%fines)
•Unsuitablefor:
–verycoarsesoils
–uniformgravels

14. 14
Equipment
Mesh (or grid pattern) roller
•50%coverage
•Masses range from 5-12 Tones
•Contactpressureisfrom1400to
6200kPa
•Compactiveeffort:staticweight
andvibration.

15. 15
Equipment
Mesh (or grid pattern) roller
•Suitable for:
–well-graded sands
–soft rocks
–stony soils with fine fractions
•Unsuitable for:
–uniform sands
–Silty sands
–Very soft clays

16. 16
Equipment
Vibrating drum on smooth-wheel roller
•Compactiveeffort:staticweight
andvibration.
•Suitableforgranularsoils

17. 17
Equipment
Vibrating Plate :
•Suitable for :
–most soils with low to moderate
fines content
•Unsuitable for:
–large volume work
–wet clayey soils

18. 18
Equipment
Power Rammer :
•Also called a trench tamper
•Suitable for :
–trench back-fill
–work in confined areas
•Unsuitable for:
–large volume work

19. 19
Variables-Vibratory Compaction
There are many variables which control the vibratory compaction or
densification of soils.
•Characteristics of the compactor:
(1) Mass, size
(2) Operating frequency and frequency range
•Characteristics of the soil:
(1) Initial density
(2) Grain size and shape
(3) Water content
•Construction procedures:
(1) Number of passes of the roller
(2) Lift thickness
(3) Frequency of operation vibrator
(4) Towing speed

20. 20
Field Compaction
Testing

21. 21
Field Density Testing Method
Field Density Testing Method
Sand Cone Balloon Dens meter Shelby Tube Nuclear Gauge
Advantages
•Large sample
•Accurate
•Large sample
•Direct readingobtained
•Open gradedmaterial
•Fast
•Deep sample
•Under pipe haunches
•Fast
•Easy to redo
•More tests (statistical reliability)
Disadvantages
•Many steps
•Large area required
•Slow
•Halt Equipment
•Tempting to accept flukes
•Slow
•Balloon breakage
•Awkward
•Small Sample
•No gravel
•Sample not always
retained
•No sample
•Radiation
•Moisture suspect
•Encourages amateurs
Errors
•Void under plate
•Sand bulking
•Sand compacted
•Soil pumping
•Surface not level
•Soil pumping
•Void under plate
•Overdrive
•Rocks in path
•Plastic soil
•Miscalibrated
•Rocks in path
•Surface prep required
•Backscatter
Cost •Low •Moderate •Low •High