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FieldCompactionEquipment

andProceduresDr.TalatBaderObjectiveoffieldCompaction

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ControlParametersTheobjectiveofcompactionistostabilizesoilsandimprovetheirengineeringbehaviorItisimportanttokeepinmindthedesiredengineeringpropertiesofthefill,dam,road,etc…Thedensityofthefillinadditiontothewatercontentshouldbeobserved.FromHoltzandKovacs,1981DesignProcedureforfieldCompactionDesignandSelectionofFillMaterialsSurveythelocalsoilsourcesthatcouldpossiblybeused.Obtainsoilsamplesfromeachsource(borrow),andperformthenecessarylaboratoryteststoclassifythesoilviaeitherAASHTO

ortheUCSsystemstodefinethepropertiesrequiredfordesign.Theclassificationitselfwilloftentellwhetherornotagivensoilissuitableforanintendedapplication.Soilswithlargeshrinkageratios(SR)shouldbeavoided.Soilswithhighplasticityindices(PI)shouldbeavoided,sincetheyindicateatendencytoshrink/expand.Organicmatterwhichcandecayshouldgenerally

beavoidedasfillmaterialunlessspecialprecautionsaretaken.DesignandSelectionofFillMaterials3)

Oncea

soilisfoundtobesuitable,foranintendedapplication,performthenecessarymoisture-densitystudy.4)Iflocalcodes/guidelinesarenotprovided,astudywouldbeneededtodeterminetheminimumrelativefieldcompactionofthesoil.Factorswouldbe:requiredshearstrengthofthesoilmaximumallowablesettlementsunderdesignloads.Aftertheearthstructureisdesigned,Thecompactionspecificationsarewritten.Fieldcompactioncontroltestsarespecified,Andtheresultsofthesebecomethestandardforcontrollingtheproject.HowtosetyourSpecificationSpecificationsEnd-productspecificationsThisspecificationisusedformosthighwaysandbuildingfoundation,aslongasthecontractorisabletoobtainthespecifiedrelativecompaction,howheobtainsitdoesn’tmatter,nordoestheequipmentheuses.Caretheresultsonly!MethodspecificationsThetypeandweightofroller,thenumberofpassesofthatroller,aswellastheliftthicknessarespecified.Amaximumallowablesizeofmaterialmayalsobespecified.Itistypicallyusedforlargecompactionproject.FromHoltzandKovacs,1981ResultsFromLaboratoryTestStandard&Modified

ProctorTestDryDensity(gd)WaterContent(w)ModifiedStandardField&LaboratoryCompactionItisdifficulttochoosealaboratorytestthatreproducesagivenfieldcompactionprocedure.Thelaboratorycurvesgenerallyyieldasomewhatloweroptimumwatercontentthantheactualfieldoptimum.Themajorityoffieldcompactioniscontrolledbythedynamiclaboratorytests.Curve1,2,3,4:laboratorycompactionCurve5,6:Fieldcompaction(FromLambeandWhitman,1979)S=100%4DryDensity(lb/ft3)12011010090DryDensity(Mg/m3)1.91.81.71.61.5WaterContent(w)1015202516523FieldCompactionEquipmentsBulldozersWateringTheBader,sCompaction

FieldEquipmentsSmooth-wheelroller(drum)100%coverageunderthewheelContactpressureupto380kPaCanbeusedonallsoiltypesexceptforrockysoils.Compactiveeffort:staticweightThemostcommonuseoflargesmoothwheelrollersisforproof-rollingsubgradesandcompactingasphaltpavement.Smooth-wheelroller(drum)Suitablefor:well-gradedsandsandgravelssiltsandclaysoflowplasticity

Unsuitablefor:uniformsands;siltysands;softclays

Pneumatic(orrubber-tired)roller80%coverageunderthewheelContactpressureupto700kPa7to13wheelsarearrangedintworows.Compactiveeffort:staticweightandkneading.DirectionofMotionPneumatic(orrubber-tired)rollerSmallTiredRollerStraightrollingWobbleActionHeavyTireRoller50to100tonsTirepressure90-150psiAdditionalweightWater,SandorSteelCanbeusedforbothgranularandfine-grainedsoils.Canbeusedforhighwayfillsorearthdamconstruction.Pneumatic(orrubber-tired)rollerSuitablefor:mostCoarsefinesoils.

Unsuitablefor:verysoftclayhighlyvariablesoils

SheepsfootrollersHasmanyroundorrectangularshapedprotrusionsor“feet〞attachedtoasteeldrum8%~12%coverageContactpressureisfrom1400to7000kPaItisbestsuitedforclayedsoils.Compactiveeffort:staticweightandkneading.looseliftofsoilcompactedlift(a)looseliftofsoilcompactedlift(b)Heavyfootedcompactorswithlargefeetthatfullypenetratealooseliftofsoilareideal.Minimumspecifications:weight:18000kgfootlength:18cmto20cmnumberofpasses:5footDrummaybeloadedwith Water SoilLoadedweightVaryfrom 6,000# 80,000#DrumDrumLengthfrom48〞to72〞DrumDiameterfrom40〞to72〞SheepsfootrollersSuitablefor:finegrainedsoilssandsandgravels,with>20%fines

Unsuitablefor:verycoarsesoilsuniformgravelsTampingfootrollerAbout40%coverageContactpressureisfrom1400to8400kPaItisbestforcompactingfine-grainedsoils(siltandclay).Compactiveeffort:staticweightandkneading.Mesh(orgridpattern)roller50%coverageMassesrangefrom5-12TonesContactpressureisfrom1400to6200kPaCompactiveeffort:staticweightandvibration.Hightowingspeed,thematerialisvibrated,crushed,andimpacted.Suitablefor:well-gradedsandssoftrocksstony

soilswithfinefractions

Unsuitablefor:uniformsandsSiltysandsVerysoftclaysVibratingdrumonsmooth-wheelrollerVerticalvibratorattachedtosmoothwheelrollers.Thebestexplanationofwhyrollervibrationcausesdensificationofgranularsoilsisthatparticlerearrangementoccursduetocyclicdeformationofthesoilproducedbytheoscillationsoftheroller.Compactiveeffort:staticweightandvibration.SuitableforgranularsoilsVibratingPlate&PowerRammerRangefromhand-guidedmachinestolargerrollercombinationsSuitablefor:mostsoilswithlowtomoderatefinescontentUnsuitablefor:largevolumeworkwetclayeysoils

Alsocalleda'trenchtamper'Hand-guidedpneumatictamperSuitablefor:trenchback-fillworkinconfinedareasUnsuitablefor:largevolumework

CompactorZonesofApplicationSheepsfootHighspeedtampingfootTowedtampingfootMultitiredpneumaticSmoothsteeldrumsVibratoryGridHeavypneumaticStaticwt,KneadingStaticwt,KneadingStaticwt,VibrationStaticwtStaticwt,KneadingStaticwt,KneadingStaticwt,Kneading100%Clay100%SandRockCompactiveEffortStaticwt,Kneading,impact,VibrationCE353Dr.TALATBADEREquipments&SoilTypeSpecialcompactionequipment

isthenusedtocompactthisliftofsoil:EquipmentType

Smooth-WheeledRollers

PneumaticRubber-TiredRollersSheepsfootRollersVibratoryRollersVibratoryTampersSoilType

sands&gravelssilts&clayssilts&clayssands&gravelssands&gravelsVariables-VibratoryCompactionTherearemanyvariableswhichcontrolthevibratorycompactionordensificationofsoils. Characteristicsofthecompactor:(1)Mass,size(2)Operatingfrequencyandfrequencyrange Characteristicsofthesoil:(1)Initialdensity(2)Grainsizeandshape(3)Watercontent Constructionprocedures:(1)Numberofpassesoftheroller(2)Liftthickness(3)Frequencyofoperationvibrator(4)TowingspeedRollerPassesWhencompactingpastfiveorsocoverage's,thereisnotagreatincreaseindensity240cmthinklayerofnorthernIndianadunesand5670kgrolleroperatingatafrequencyof27.5Hz.HoltzandKovacs,198102rollerpasses05rollerpasses15rollerpasses45rollerpasses405060708090100RelativeDensity(%)95100105110Drydensity(lb/ft3)0234561Depth(ft)InitialfilldensityRollerPassesLowCompactionatthesurfaceMax.Dr.isapproximately½meterbellowthesurface.Mosteffectivecompactionisdoneduringthefirst5-7passes.HoltzandKovacs,198102rollerpasses05rollerpasses15rollerpasses45rollerpasses405060708090100RelativeDensity(%)95100105110Drydensity(lb/ft3)0234561Depth(ft)InitialfilldensityDensity-depthrelationshipforlargeliftheightusing5rollerpasses

DeterminetheLiftHeight0.00.51.00.5Minimumallowablerelativedensity=75%60708090500123456Relativedensity(%)Depth(ft)(m)Formostcompactionequipment,liftthicknessesshouldtypicallybeontheorderofsixinches(6")or15cmifnoexperienceortesting18

inDeterminetheLiftHeight0.00.51.00.5Density-depthrelationshipforlargeliftheightusing5rollerpasses60708090500123456Relativedensity(%)Depth(ft)(m)Formostcompactionequipment,liftthicknessesshouldtypicallybeontheorderofsixinches(6")or15cmifnoexperienceortestingLiftThicknessIfliftthicknessesaretoolarge:Soilatthetopoftheliftwillbewell-compacted.Soilatthebottomoftheliftwillnotbecompacted.Why?ThisissometimescalledtheOreo-Cookieeffect.TheWheelofcompactionequipmentHighstressregioniswell-compactedLowstressregionisnotWellcompactedFFrequencyCompactedDensityincreaseswithincreasingoperationfrequency.Theoperatingfrequencyshouldbeatleastaslargeastheresonantfrequencytoobtainthemostefficientuseofthe95100105110Drydensity(lb/ft3)0234561Depth(ft)405060708090100RelativeDensity(%)20Hz30HzFrequencyThefrequencyatwhichamaximumdensityisachievediscalledtheoptimumfrequenc