field compaction equipment and procedures

Field Compaction Field Compaction EquipmentEquipment

and Procedures and Procedures

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Objective of field Objective of field CompactionCompaction

&&

Control ParametersControl ParametersThe objective of compaction is to The objective of compaction is to stabilize soils and improve their stabilize soils and improve their engineering behaviorengineering behavior

It is important to keep in mind the It is important to keep in mind the desired engineering properties of the desired engineering properties of the fill, dam, road, etc…fill, dam, road, etc…

The density of the fill in addition to The density of the fill in addition to the water content should be observed.the water content should be observed.From Holtz and Kovacs, 1981http://omidi2010.blogsky.comhttp://omidi2010.blogsky.com

Design Procedure for Design Procedure for field Compactionfield Compaction


Design and Selection of Design and Selection of Fill MaterialsFill Materials

1)1) Survey the local soil sources that could Survey the local soil sources that could possibly be used.possibly be used.

2)2) Obtain soil samples from each source Obtain soil samples from each source (borrow), and perform the necessary (borrow), and perform the necessary laboratory tests to classify the soil via either laboratory tests to classify the soil via either AASHTO or the UCS systems to define the properties required for design.

The classification itself will often tell whether or not a given soil is suitable for an intended application.

Soils with large shrinkage ratios (SR) should be avoided.

Soils with high plasticity indices (PI) should be avoided, since they indicate a tendency to shrink/expand.

Organic matter which can decay should generally be avoided as fill material unless special precautions are taken.http://omidi2010.blogsky.comhttp://omidi2010.blogsky.com

Design and Selection of Design and Selection of Fill MaterialsFill Materials

3)3) Once a soil is found to be suitable, for an Once a soil is found to be suitable, for an intended application, perform the necessary intended application, perform the necessary moisture-density study.moisture-density study.

4) If local codes/guidelines are not provided, a 4) If local codes/guidelines are not provided, a study would be needed to determine the study would be needed to determine the minimum relative field compaction of the soil. minimum relative field compaction of the soil. Factors would be:Factors would be: required shear strength of the soilrequired shear strength of the soil maximum allowable settlements under design maximum allowable settlements under design

loadsloads..

5)5) After the earth structure is designed,After the earth structure is designed,– The compaction specifications are written.The compaction specifications are written.– Field compaction Field compaction control testscontrol tests are specified, are specified,– And the results of these become the standard for And the results of these become the standard for

controlling the project.controlling the project.


How to set your How to set your SpecificationSpecification


SpecificationsSpecifications1)1) End-product specificationsEnd-product specifications

This specification is used for most highways This specification is used for most highways and building foundation, as long as the and building foundation, as long as the contractor is able to obtain the specified contractor is able to obtain the specified relative compactionrelative compaction , how he obtains it doesn’t , how he obtains it doesn’t matter, nor does the equipment he uses.matter, nor does the equipment he uses.

Care the results only !Care the results only !

2)2) Method specificationsMethod specificationsThe type and weight of roller, the number of The type and weight of roller, the number of passes of that roller, as well as the lift passes of that roller, as well as the lift thickness are specified. A maximum allowable thickness are specified. A maximum allowable size of material may also be specified.size of material may also be specified.

It is typically used for large compaction It is typically used for large compaction project.project.

From Holtz and Kovacs, 1981


Results From Results From Laboratory Test Laboratory Test


Standard & ModifiedStandard & ModifiedProctor TestProctor Test

Dry

Den

sit

y (

d)

Water Content (w)

Modified

Standard


Field & Laboratory Field & Laboratory CompactionCompaction

•It is difficult to choose a It is difficult to choose a laboratory test that laboratory test that reproduces a given field reproduces a given field compaction procedure.compaction procedure.

•The laboratory curves The laboratory curves generally yield a generally yield a somewhat lower somewhat lower optimum water content optimum water content than the actual field than the actual field optimum.optimum.

•The majority of field The majority of field compaction is compaction is controlled by the controlled by the dynamic laboratory dynamic laboratory teststests..

Curve 1, 2,3,4: laboratory compaction

Curve 5, 6: Field compaction

(From Lambe and Whitman, 1979)

S = 100%

S = 100%

4

Dry

Den

sit

y (

lb/f

t3)

120120

110110

100100

9090

Dry

Den

sit

y (

Mg

/m3)

1.91.9

1.81.8

1.71.7

1.61.6

1.51.5

Water Content (w)

1010 1515 2020 2525

1

65

2

3


Field Compaction Field Compaction EquipmentsEquipments


BulldozersBulldozers


WateringWatering

The Bader,s


Compaction Compaction Field EquipmentsField Equipments


Smooth-wheel roller Smooth-wheel roller (drum)(drum)

100% coverage under 100% coverage under the wheelthe wheel

Contact pressure up to Contact pressure up to 380 kPa380 kPa

Can be used on all soil Can be used on all soil types except for rocky types except for rocky soils.soils.

Compactive effort: Compactive effort: static weight static weight

The most common use The most common use of large smooth wheel of large smooth wheel rollers is for proof-rollers is for proof-rolling subgrades and rolling subgrades and compacting asphalt compacting asphalt pavement.pavement.http://omidi2010.blogsky.comhttp://omidi2010.blogsky.com

Smooth-wheel roller Smooth-wheel roller (drum)(drum)

Suitable for:Suitable for:– well-graded sands well-graded sands

and gravelsand gravels– silts and clays of low silts and clays of low

plasticityplasticity

Unsuitable for:Unsuitable for:– uniform sands;uniform sands;– silty sands;silty sands;

– soft clayssoft clays


Pneumatic (or rubber-tired) Pneumatic (or rubber-tired) rollerroller

80% coverage under the wheel

Contact pressure up to 700 kPa

7 to 13 wheels are arranged in two rows.

Compactive effort: static weight and kneading.

Direction of Motion



Small Tired RollerStraight rollingWobble Action

Heavy Tire Roller50 to 100 tonsTire pressure 90-150 psiAdditional weight

– Water, Sand or Steel

Can be used for both granular and fine-grained soils.

Can be used for highway fills or earth dam construction.



Suitable for: most – Coarse– fine soils.

Unsuitable for:– very soft clay– highly variable

soils http://omidi2010.blogsky.comhttp://omidi2010.blogsky.com

Sheepsfoot rollersSheepsfoot rollersHas many round or Has many round or rectangular shaped rectangular shaped protrusions or “feet” protrusions or “feet” attached to a steel drumattached to a steel drum

8% ~ 12 % coverage8% ~ 12 % coverage

Contact pressure is from Contact pressure is from 1400 to 7000 kPa1400 to 7000 kPa

It is best suited for It is best suited for clayed soils.clayed soils.

Compactive effort: static Compactive effort: static weight and kneading.weight and kneading.


loose liftof soil

compacted lift

(a)

loose liftof soil

compacted lift

(b)

Heavy footed compactors Heavy footed compactors with large feet that fully with large feet that fully penetrate a loose lift of penetrate a loose lift of soil are ideal.soil are ideal.

Minimum Minimum specifications:specifications:

• weight : 18000 kgweight : 18000 kg

• foot length: 18 cm to 20 foot length: 18 cm to 20 cmcm

• number of passes: 5number of passes: 5

footfoot


Drum may be loaded Drum may be loaded withwith

WaterWater

SoilSoil

Loaded weight Vary Loaded weight Vary fromfrom

6,000 #6,000 #

80,000 #80,000 #

DrumDrum

Drum Length from 48” to 72”

Drum Diameter from 40” to 72”


Sheepsfoot rollersSheepsfoot rollers

Suitable for:Suitable for:– fine grained soilsfine grained soils– sands and sands and

gravels, with gravels, with >20% fines>20% fines

Unsuitable for:Unsuitable for:– very coarse soilsvery coarse soils– uniform gravelsuniform gravels


Tamping foot rollerTamping foot roller

About 40% coverage About 40% coverage

Contact pressure is Contact pressure is from 1400 to 8400 from 1400 to 8400 kPakPa

It is best for It is best for compacting fine-compacting fine-grained soils (silt grained soils (silt and clay).and clay).

Compactive effort: Compactive effort: static weight and static weight and kneading.kneading.


Mesh (or grid pattern) Mesh (or grid pattern) rollerroller

50% coverage50% coverage

Masses range from 5-12 Masses range from 5-12 TonesTones

Contact pressure is from Contact pressure is from 1400 to 6200 kPa1400 to 6200 kPa

Compactive effort: static Compactive effort: static weight and vibration.weight and vibration.

High towing speed, the High towing speed, the material is vibrated, material is vibrated, crushed, and impacted.crushed, and impacted.

Suitable for:Suitable for:– well-graded sandswell-graded sands– soft rockssoft rocks– stony soils with fine fractionsstony soils with fine fractions

Unsuitable for:Unsuitable for:– uniform sandsuniform sands– Silty sandsSilty sands– Very soft clays Very soft clays


Vibrating drum on smooth-Vibrating drum on smooth-wheel rollerwheel roller

Vertical vibrator attached Vertical vibrator attached to smooth wheel rollers.to smooth wheel rollers.

The best explanation of The best explanation of why roller vibration why roller vibration causes densification of causes densification of granular soils is that granular soils is that particle rearrangement particle rearrangement occurs due to cyclic occurs due to cyclic deformation of the soil deformation of the soil produced by the produced by the oscillations of the roller.oscillations of the roller.

Compactive effort: static Compactive effort: static weight and vibration.weight and vibration.

Suitable for granular Suitable for granular soilssoils


Vibrating Plate & Power Vibrating Plate & Power RammerRammer

Range from hand-guided Range from hand-guided machines to larger roller machines to larger roller combinations combinations

Suitable for:Suitable for:– most soils with low to most soils with low to

moderate fines moderate fines content content

Unsuitable for:Unsuitable for:– large volume worklarge volume work– wet clayey soilswet clayey soils

Also called a 'trench Also called a 'trench tamper' tamper'

Hand-guided pneumatic Hand-guided pneumatic tamper tamper

Suitable for:Suitable for:– trench back-filltrench back-fill– work in confined areas work in confined areas

Unsuitable for:Unsuitable for:– large volume worklarge volume work


Compactor Zones of Compactor Zones of ApplicationApplication

SheepsfootSheepsfoot

High speed tamping footHigh speed tamping foot

Towed tamping footTowed tamping foot

Multitired pneumaticMultitired pneumatic

Smooth steel drumsSmooth steel drums

VibratoryVibratory

GridGrid

Heavy pneumaticHeavy pneumatic

Static wt, KneadingStatic wt, Kneading


Static wt, VibrationStatic wt, Vibration

Static wtStatic wt




100 %100 %ClayClay

100 %100 %SandSand RockRock Compactive EffortCompactive Effort

Static wt, Kneading, impact, VibrationStatic wt, Kneading, impact, Vibration

C

E

3

5

3

Dr.

T

A

L

A

T

B

A

D

E

R


Equipments & Soil TypeEquipments & Soil Type

Special compaction equipment is Special compaction equipment is then used to compact this lift of soil:then used to compact this lift of soil:

Equipment TypeEquipment Type • Smooth-Wheeled Rollers• Pneumatic Rubber-Tired

Rollers• Sheepsfoot Rollers• Vibratory Rollers• Vibratory Tampers

Soil TypeSoil Type • sands & gravels • silts & clays • silts & clays• sands & gravels • sands & gravels


Variables-Vibratory Variables-Vibratory CompactionCompaction

There are many variables which control the There are many variables which control the vibratory compaction or densification of vibratory compaction or densification of soils.soils.

Characteristics of the compactor:Characteristics of the compactor:(1) Mass, size(1) Mass, size(2) Operating frequency and frequency range(2) Operating frequency and frequency range

Characteristics of the soil:Characteristics of the soil:(1) Initial density(1) Initial density(2) Grain size and shape(2) Grain size and shape(3) Water content(3) Water content

Construction procedures:Construction procedures:(1) Number of passes of the roller(1) Number of passes of the roller(2) Lift thickness(2) Lift thickness(3) Frequency of operation vibrator(3) Frequency of operation vibrator(4) Towing speed(4) Towing speed


Roller PassesRoller Passes

When compacting When compacting past five or so past five or so coverage's, there coverage's, there is not a great is not a great increase in densityincrease in density

240 cm think layer of 240 cm think layer of northern Indiana dune northern Indiana dune sandsand

5670 kg roller 5670 kg roller operating at a operating at a frequency of 27.5 Hz.frequency of 27.5 Hz.

Holtz and Kovacs, 1981

02 roller passes 05 roller passes 15 roller passes

45 roller passes

40 50 60 70 80 90 100Relative Density (%)

95 100 105 110

Dry density (lb/ft3)

0

2

3

4

5

6

1

Depth

(f

t)

Init

ial fill

densi

ty


Roller PassesRoller Passes

Low Low Compaction at Compaction at the surfacethe surface

Max. Dr. is Max. Dr. is approximately ½ approximately ½ meter bellow the meter bellow the surface.surface.

Most effective Most effective compaction is compaction is done during the done during the first 5-7 passes.first 5-7 passes.

Holtz and Kovacs, 1981

02 roller passes 05 roller passes 15 roller passes

45 roller passes


95 100 105 110


0

2

3

4

5

6

1

Depth

(f

t)

Init

ial fill

densi

ty


Density-depth relationship for large liftlarge lift height

using 5 roller passes

Determine the Lift Determine the Lift HeightHeight

0.0

0.5

1.0

0.5

Minimum Minimum allowable allowable relative relative

density = density = 75%75%

60 70 80 90500

1

2

3

4

5

6

Relative density (%)Relative density (%)

Depth

(ft

) D

epth

(ft

) (m

)(m

)

For most For most compactiocompaction n equipmentequipment, lift , lift thicknessethicknesses should s should typically typically be on the be on the order of order of six inches six inches (6") or (6") or 15cm if no 15cm if no experience experience or testingor testing

1818 inin


Determine the Lift Determine the Lift HeightHeight

0.0

0.5

1.0

0.5 Density-depth relationship for large liftlarge lift height

using 5 roller passes

60 70 80 90500

1

2

3

4

5

6

Relative density (%)Relative density (%)

Depth

(ft

) D

epth

(ft

) (m

)(m

)

For most For most compactiocompaction n equipmentequipment, lift , lift thicknessethicknesses should s should typically typically be on the be on the order of order of six inches six inches (6") or (6") or 15cm if no 15cm if no experience experience or testingor testing


Lift ThicknessLift ThicknessIf lift thicknesses are too large:If lift thicknesses are too large:Soil at the top of the lift will be well-Soil at the top of the lift will be well-

compacted. compacted. Soil at the bottom of the lift will not Soil at the bottom of the lift will not

be compacted. be compacted. Why?Why?This is sometimes called the Oreo-This is sometimes called the Oreo-

Cookie effectCookie effect..

The Wheel of compaction equipmentThe Wheel of compaction equipment

High stress region is well-compactedHigh stress region is well-compactedLow stress region is not Well Low stress region is not Well compactedcompacted

FF


FrequencyFrequency• Compacted Compacted Density Density increases with increases with increasing increasing operation operation frequency.frequency.

• The operating The operating frequency frequency should be at should be at least as large as least as large as the resonant the resonant frequency to frequency to obtain the most obtain the most efficient use of efficient use of thethe

95 100 105 110


0

2

3

4

5

6

1

Depth

(f

t)


20 Hz 30 Hz


FrequencyFrequency

The frequency at The frequency at which a which a

maximum maximum density is density is

achieved is achieved is called the called the optimum optimum

frequency.frequency.Roller wt. in lb

= 3600 = 5800 = 7500a = 7500b = 17000

1000 2000 3000

150

140

130

120

110

100

90

Dry

Densi

ty (

lb/f

t3)

Vibration frequency (cpm)

Heavy clay

Heavy clayHeavy clay

Clay soil

Gravelly sand

Gravel-sand-clay

Uniform sand

Well-graded sand

Gravelly sand


StressesStresses

)()(@)( passiveprestoactivea KKK

Horizontal stress measurements indicated that Horizontal stress measurements indicated that lateral stresses are much grater than at rest lateral stresses are much grater than at rest condition.condition.

20

1.0

3.0

2.0

0 84 12 16

Dry

Densi

ty (

lb/f

t3)

Lateral stresses were found to increase with Lateral stresses were found to increase with

Number of passesNumber of passes

Operating frequenciesOperating frequencies

v

h

v

hoK

Parallel to roller pathPerpendicular to

roller path


Roller Travel SpeedRoller Travel SpeedFor a given number For a given number of passes, a higher of passes, a higher density is obtained if density is obtained if the vibrator is towed the vibrator is towed more slowly.more slowly.

20

110

140

130

120

100

0 84 12 16

1.60

2.00

1.90

1.80

1.70

110

100

090

080 1.28

1.76

1.64

1.52

1.40

2.25 mph

1.50 mph

0.75 mph

Dry

Densi

ty (

lb/f

t3)

Roller Coverage

Mg/m

3 For the same speed, For the same speed, the higher the the higher the number of passes number of passes the higher the the higher the densitydensity

Well graded sand(moisture = 7.5 %)

Heavy clay(moisture = 21 %)


Thank youThank you


field compaction equipment and procedures

Documents

field compaction http

field laboratory compaction

compaction specifications

field compaction equipment

objective of compaction

standard http

laboratory test http

specified relative compaction