In Situ Testing Methods in Geotechnical Engineering

IntroductionRole of In Situ Testing In Site InvestigationsAdvantages and Limitations of In Situ TestsAdvantages of In Situ TestsTesting Soils that are Difficult to SampleDetermining Soil Properties that are Difficult to Measure by Laboratory MethodsTesting a Larger Volume of SoilAvoiding Difficulties with Sampling and Laboratory TestingObtaining Near Continuous ProfilingReduced Testing TimeRapid Data ReductionAssessing the Influence of Scale or Macro-Fabric on Soil BehaviorConducting Tests in a Field EnvironmentCost SavingsLimitations of In Situ TestsUnknown Boundary ConditionsUnknown Drainage ConditionsUnknown DisturbanceModes of Deformation and Failure May be UniqueStrain Rates or Loading Rates are Higher than Laboratory and Full-ScaleNature of the Soil Being Tested is UnknownEffects of Environment Change on Soil Behavior are Difficult to AssessTypical Difficulties with Field WorkApplications of In Situ TestsStratigraphic ProfilingSpecific Property MeasurementPrototype ModelingInterpretation of In Situ Test ResultsUsing In Situ Tests in DesignIndirect DesignDirect DesignReferencesStandard Penetration Test (SPT)IntroductionBackgroundMechanics of the TestEquipmentHammerDrill RodsSplit Barrel SamplerTest ProceduresFactors Affecting Test ResultsEnergy Delivered to the SamplerSPT Hammer Energy CalibrationOther Factors Affecting SPT ResultsDiameter of Drill RodsDrill Rod LengthSampler DimensionsDiameter of BoreholeMethod of Drilling/Drilling FluidCleanout of the BoreholeRate of TestingSeating of the SpoonCondition of the Drive ShoeSummaryCorrections to SPT Blow CountsCorrections for Hammer Energy, Equipment, and Drilling: N to N60Correction for Overburden Stress in Sands: N60 to (N1)60Interpretation of Soil PropertiesSPT in Coarse-Grained SoilsRelative DensityFriction AngleSoil Elastic ModulusConstrained ModulusSmall-Strain Shear ModulusLiquefaction PotentialSPT in Fine-Grained SoilsUndrained Shear StrengthStress HistoryIn Situ Lateral StressSoil Elastic ModulusSmall-Strain Shear ModulusSPT in Soft/Weak RockImprovements to SPT PracticeSPT-T TestSeismic SPTMeasurement of Penetration RecordIncremental Penetration RatioDifferential Penetration RecordLarge Penetration TestBecker Penetration TestSPT in Geotechnical DesignShallow FoundationsDeep FoundationsSummary of SPTReferencesDynamic Cone Penetration Test (DCP)IntroductionMechanicsEquipmentTest ProceduresLight DCPSowers ConeASTM Light “Pavement” DCPMackintosh & JKR ProbeLutenegger Drive ConeMedium DCPHeavy DCPSuper Heavy DCPTexas Cone PenetrometerSwedish Ram Sounding TestFactors Affecting Test ResultsPresentation of Tests ResultsIncremental Penetration ResistanceCumulative Penetration ResistancePenetration Distance per Hammer BlowDynamic Penetration ResistanceInterpretation of Test ResultsCorrelations to SPTCorrelations to CPTDirect Correlations to Soil PropertiesRelative Density of SandsUndrained Shear Strength of ClaysCalifornia Bearing RatioResilient ModulusCompaction ControlSummary OF DCPReferencesCone Penetration (CPT) and Piezocone (CPTU) TestsIntroductionMechanics of the Test – CPT/CPTUMechanical ConesElectric ConesElectric PiezoconeDeploying Cone PenetrometersSelf-Contained TruckDrill RigLight-Duty TrailerPortable Reaction FrameTest ProceduresFactors Affecting Test ResultsCone DesignCone DiameterRate of PenetrationSurface Roughness of Friction SleeveData Reduction and Presentation of ResultsInterpretation of Results for StratigraphySoil Identification from qc, fs, and RfSoil Identification from qt, Bq, and RfSoil Identification from Qt, Bq, and FrSoil Behavioral Type from CPTU, IC, and ICRWInterpretation of Test Results in Coarse-Grained SoilsRelative DensityState ParameterShear Strength (Drained Friction Angle)ȹ' from Deep Bearing Capacity Theoryȹ' from State ParameterStress History and In Situ StressElastic ModulusConstrained ModulusShear Wave Velocity and Small-Strain Shear ModulusShear Wave Velocity and Shear Modulus from qcLiquefaction PotentialInterpretation of CPT Results in Fine-Grained SoilsUndrained Shear Strengthsu from qcsu from qTsu from usu from qT and usu from Qsu from fssu from Ϭ'pSensitivityStress history – Preconsolidation Stress, Ϭ'pϬ'P from qcϬ'P from qtc'p from ΔuϬ'P from qt and uStress History – OCROCR from qcOCR from qt and uOCR from Pore Pressure DifferenceIn Situ Lateral StressKo from OCREmpirical Correlations to qt and ΔuShear Wave Velocity and Small-Strain Shear ModulusShear Wave Velocity from qc and qtShear Wave Velocity from fsShear Modulus from qc and qtConstrained ModulusCoefficient of ConsolidationHydraulic ConductivityAdvantages and Limitations of CPT/CPTUCPT-SPT CorrelationsCPT/CPTU in Foundation DesignShallow FoundationsDeep FoundationsSummary of CPT/CPTUReferencesField Vane Test (FVT)IntroductionMechanicsEquipmentUnprotected Vane Through CasingProtected Rods and Unprotected VaneProtected Rods and Protected VaneUnprotected Rods and Unprotected Vane with Slip CouplingVanesTest ProceduresFactors Affecting Test ResultsInstallation EffectsDisturbanceInsertion Pore Water PressuresDelay (Consolidation) TimeRate of ShearingProgressive FailureVane SizeVane ShapeInterpretation of Undrained Strength from FVTAnisotropic AnalysisMeasuring Postpeak StrengthField Vane Correction FactorsInterpretation of Stress History from FVTSummary of FVTReferencesDilatometer Test (DMT)IntroductionMechanicsEquipmentTest ProcedureLift-off Pressuremm Expansion PressureRecontact PressureData ReductionLift-off and Penetration Pore Pressuresmm Expansion PressureRecontact PressurePresentation of Test ResultsInterpretation of Test ResultsEvaluating StratigraphyInterpretation of DMT Results in Fine-Grained SoilsUndrained Shear StrengthMarchetti Method (1980)Roque etal. Method (1988)Schmertmann Method (1989)“Effective” Lift-Off Pressure MethodLarsson & Eskilson (1989) “effective” I mm Expansion Pressure MethodYu e tal. (1993)Kamei and Iwasaki Method (1995)Lutenegger Cavity Expansion “effective stress” Method (2006)Stress History - OCRMarchetti MethodCavity Expansion MethodPreconsolidation StressMayne Method (1987)Cavity Expansion “effective stress’’ MethodLateral StressesConstrained ModulusElastic ModulusSmall-Strain Shear ModulusLiquidity IndexCalifornia Bearing RatioCoefficient of ConsolidationDMTC (P2) DissipationDMTA DissipationInterpretation of DMT Results in Coarse-Grained SoilsRelative Density (Dr)State ParameterDrained Friction AngleSchmertmann MethodCampanella and Robertson MethodMarchetti MethodIn Situ StressesStress HistoryConstrained ModulusElastic ModulusSmall-Strain Shear ModulusCoefficient of Subgrade ReactionLiquefaction PotentialSeismic DilatometerDesign ApplicationsSummary of DMTReferencesPressuremeter Test (PMT)IntroductionMechanics of the TestPressuremeter EquipmentPrebored PressuremetersTri-Cell ProbeMono-Cell ProbeSelf-Boring PressuremetersFull-Displacement (Cone) PressuremetersPush-in PressuremeterCreating a Borehole for the PMTTest ProceduresTest Procedure A – Equal-Pressure Increment MethodTest Procedure B – Equal-Volume Increment MethodContinuous Loading TestsHolding TestsData ReductionCorrected Pressure-Volume CurveInitial Pressure, PОCreep Pressure, PfLimit Pressure, PLNet Limit Pressure, PL*Pressuremeter Modulus, EmUnload-Reload Modulus, EURCreep CurveRelationships Between PMT ParametersFactors Affecting Test ResultsMethod of InstallationCalibration of MembraneVolume LossesGeometry of Cutter (SBPMT)Rate of Installation (SBPMT)Interpretation of Tests Results in Fine-Grained SoilsIn Situ Horizontal StressUndrained Shear StrengthPreconsolidation StressSmall-Strain Shear ModulusInterpretation of Test Results in Coarse-Grained SoilsPressuremeter Testing in RockCorrelations with Other In Situ TestsApplications to DesignDesign of Shallow FoundationsBearing CapacitySettlementDeep FoundationsUltimate Axial Load of Deep FoundationsLaterally Loaded Shafts and PilesSummary of PMTReferencesBorehole Shear Test (BST)IntroductionMechanicsEquipmentShear HeadControl ConsoleShear Force Reaction Base PlateTest ProceduresMultistage TestingSingle-Stage “Fresh” TestingBorehole PreparationInterpretation of Test ResultsRange of Soil ApplicabilityFactors Affecting Test ResultsInterface Shear TestsComparison with Laboratory TestsEquipment ModificationsApplications of BST for DesignAdvantages and LimitationsAdvantagesLimitationsSummary of BSTReferencesPlate Load Test (PLT) and Screw Plate Load Test (SPLT)IntroductionPlate Load TestEquipmentTest ProceduresTests on the Ground SurfaceTests in an Excavation/Test PitTests in Lined BoringsHorizontal Plate Load TestsScrew Plate TestsEquipmentTest ProceduresPresentation of Test ResultsInterpretation of ResultsSubgrade Reaction ModulusElastic ModulusPlate Load TestScrew Plate TestShear ModulusUndrained Shear Strength of ClaysCoefficient of ConsolidationPlate Load as a Prototype FootingSummary of PLT and SPLTReferencesOther In Situ TestsIntroductionLarge-Scale In-Place Shear Box TestsBackgroundTest EquipmentTest ProceduresResults and InterpretationHydraulic Fracture Tests (HFTs)BackgroundTest EquipmentTests with Push-in PiezometerTests in an Open BoreholeTest ProceduresResults and InterpretationPush-in Earth Pressure CellsBackgroundTest EquipmentTest ProceduresResults and InterpretationReferences
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