基桩低应变完整性测试方法标准中英文

PAGEPAGE11Designation:D5882–00定名：D5882-00StandardTestMethodforLowStrainIntegrityTestingofPiles1基桩低应变完整性测试方法标准ThisstandardisissuedunderthefixeddesignationD5882;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.本标准出版的固定名称为D5882;紧接其后的数字代表了最初采用的年份，或修订的年份，或最后修订的年份。圆括号内的数字代表了最后被再次正式批准的年份。上角标（ε）表明从最近的修订或再次批准之后有一个编辑上的改变。1.Scope适用范围1.1Thistestmethod2coverstheprocedurefordeterminingtheintegrityofindividualverticalorinclinedpilesbymeasuringandanalyzingthevelocity(required)andforce(optional)responseofthepileinducedbyan(handheldhammerorothersimilartype)impactdeviceappliedaxiallytothepilenormallyatthepilehead.Thistestmethodisapplicabletolongstructuralelementsthatfunctioninamannersimilartofoundationpiles,regardlessoftheirmethodofinstallationprovidedthattheyarereceptivetolowstrainimpacttesting.该规程适用于检测垂直或倾斜基桩的完整性。采用的方法是通过手锤或类似物，通常轴向敲击桩顶，在桩顶测量并记录速度（必须地）及力（可选择地）的时程信号，对此进行分析。该测试方法也适用于检测类似基础桩的长状体结构，无论其如何施工，只要低应变激发测试可以利用即可。1.2Thisstandardmayinvolvehazardousmaterials,opera-tions,andequipment.Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.Fig.该规程可能要求接触有害的材料、操作及设备。若该规程中未说明的安全提示，请参照相关标准执行。在本规范的执行中，保证安全及健康，在测试前判定操作行为局限性及适用性是操作者的责任。2.ReferencedDocuments参考文献2.1ASTMStandards:ASTM标准：C469TestsMethodforStaticModulusofElasticityandPoisson’sRatioofConcreteinCompression3C469受压状态下混凝土静弹性模量及泊松比的测试方法D198MethodsofStaticTestsofTimbersinStructuralSizes4D198木桩的原位静力测试方法4D653TerminologyRelatingtoSoil,Rock,andContainedFluids5D653土壤、岩石及包装流体的相关技术术语5D1143MethodofTestingPilesunderStaticAxialCompressiveLoad5D1143基桩静力轴向抗压测试方法5D4945TestMethodforHighStrainDynamicTestingofPiles6D4945基桩高应变动力测试方法63.Terminology术语3.1Exceptasdefinedin3.2,theterminologyusedinthistestmethodconformswithTerminologyD653.除3.2以外，本规程中的术语均服从D653规程3.2DefinitionsofTermsSpecifictoThisStandard:本规程术语：————————————————————1ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoilandRockandisthedirectresponsibilityofSubcommitteeD18.11onDeepFoundations.CurrenteditionapprovedNovember10,2000.PublishedNovember2000.OriginallypublishedasD5882–95.LastpreviouseditionD5882–95.2Low-straindynamictestingisanondestructivemethodusinglightweightequipmenttoassessonlytheintegrityofthepileshaft.3AnnualBookofASTMStandards,Vol04.02.4AnnualBookofASTMStandards,Vol04.10.5AnnualBookofASTMStandards,Vol04.08.6AnnualBookofASTMStandards,Vol04.0pileintegrity,n—thequalitativeevaluationofthephysicaldimensions,continuityofapile,andconsistencyofthepilematerial.桩身完整性-对基桩就桩身3.2.2pileimpedance,n—thedynamicYoung’smodulusofthepilematerialmultipliedbytheapplicablecrosssectionalareaofthepileanddividedbythestrainwavespeed.桩身阻抗-FIG.1TypicalVelocityTracesGeneratedbytheApparatusforObtainingDynamicMeasurements图1由动态测试仪获得的典型的速度曲线图3.2.3pulseechomethod,n—testinwhichmeasurementsofthepileheadvelocityandforce(forcemeasurementoptional)areevaluatedasafunctionoftime.声波脉冲反射法-测量桩顶的速度及力（力3.2.4transientresponsemethod,n—testinwhichtheratioofvelocitytransformtoforcetransform(forcemeasurementrequired)areevaluatedasafunctionoffrequency.瞬态响应法-将速度变换与力的变换（力必测）的比值，作为频率的函数被进行评价的测试。4.SignificanceandUse意义及运用4.1Lowstrainintegritytestingprovidesvelocityandforce(optional)dataonstructuralelements(thatis,structuralcolumns,drivenconcretepiles,castinplaceconcretepiles,concretefilledsteelpipepiles,timberpiles,etc.).Thisdataassistsevaluationofpileintegrityandpilephysicaldimensions(thatis,cross-sectionalarea,length),continuity,andconsistencyofthepilematerial.Thistestmethodwillnotgiveinformationregardingthepilebearingcapacity.低应变测试提供测试建筑结构单元的速度及力（非必测）的数据（例如结构柱子、打入式混凝土桩、混凝土灌注桩、内浇筑混凝土钢管桩、木桩等等）。这些数据有助于我们评价桩身的完整性、桩身尺寸（截面积及长度）、桩身的连续性及桩身材质的坚固性。该方法将无法得到桩承载能力的相关信息。4.1.1MethodsofTesting测试方法PulseEchoMethod(PEM)—Thepileheadmotionismeasuredasafunctionoftime.Thetimedomainrecordisthenevaluatedforpileintegrity.声波脉冲反射法（PEM）-将桩顶的运动以时间函数进行测量，得到的时间域记录用于评价桩身完整性。TransientResponseMethod(TRM)—Thepileheadmotionandforce(measuredwithaninstrumentedhammer)aremeasuredasafunctionoftime.Thedataareevaluatedusuallyinthefrequencydomain.瞬态响应法（TRM）-将桩顶的运动及力（由专用手锤测量）以时间函数进行测量，得到的数据通常在频率域内进行评价的方法。5.Apparatus仪器设备5.1ApparatusforApplyingImpact实现激振的设备5.1.1ImpactForceApplication—Theimpactmaybedeliveredbyanydevice(forexample,ahandheldhammer)thatwillproduceaninputforcepulseofgenerallylessthan1msdurationandshouldnotcauseanylocalpiledamageduetotheimpact.Ahammerwithaveryhardplastictipcaninduceashortinputforcepulsewithoutcausinglocalpiledamage.Theimpactshouldbeappliedaxiallytothepile(normallyonthepilehead).激振力的得到-激振力可以用任何材料的到，如手锤，要求产生的激振力脉冲持续时间通常少于1毫秒，而且敲击时不应损伤桩顶的混凝土。如果使用尖端镶嵌了坚硬塑料的手锤敲击桩顶，将会产生窄短的脉冲力而不伤害桩顶。敲击方向应确保与桩轴线一致（正常状态下在桩顶敲击）。5.2ApparatusforObtainingMeasurements完成测量的设备5.2.1VelocityMeasurement—Obtainvelocitydatawith(oneormore)accelerometers,providedtheaccelerationsignal(s)canbeintegratedtovelocityintheapparatusforreducingdata.Theaccelerometer(s)shouldbeplacedat(ornear)thepileheadandshallhavetheirsensitiveaxisparallelwiththepileaxis.Accelerometersshallbelineartoatleast50g.EitherA/CorD/Caccelerometerscanbeused.IfA/Cdevicesareused,thetimeconstantshallbegreaterthan0.5sandtheresonantfrequencyshallbeatleast30000Hz.IfD/Cdevicesareused,theyshallhavefrequencyresponseupto5000Hzwithlessthan−3dBreductionofcontent.Alternatively,velocityordisplacementtransducersmaybeusedtoobtainvelocitydata,providedtheyareequivalentinperformancetothespecifiedaccelerometers.Calibratethetransducertoanaccuracyof5%throughouttheapplicablemeasurementrange.Ifdamageissuspectedduringuse,recalibrateorreplacetheaccelerometer.速度测量-速度数据是由加速度计（1个或2个）获得的，倘若加速度信号可以在仪器中被还原，经过积分处理便得到速度。加速度计应安装在桩顶或其附近，且其测试方向应与桩轴线一致。加速度计的线性范围应能达到50个重力加速度。无论在瞬态还是稳态条件下均可以满足使用。如果是瞬态装置，时间常数应大于0.5秒，共振频率应不小于30000赫兹。如果在稳态装置中，在达到5000赫兹时，频响误差应小于-3分贝。同样，速度计或位移计均可以获得速度信号，只要它们的性能满足要求即可。5.2.2ForceMeasurement(optional)—Theimpactdeviceshallbecapableofmeasuringtheimpactforceasafunctionoftime.Thehammermayhaveaforceloadcellbetweenthetipandhammerbody.Alternatively,thehammermayhaveanaccelerometerattachedandthemeasuredaccelerationmaybeconvertedtoforceusingthehammermass.Theforcecalibrationshallbewithin5%.Thehammermustbetunedsuchthatthefourriertransformofthemeasuredforceshallhaveasmoothspectrum,withoutanylocalpeaks.力的测量（非必测）-敲击设备应该具备以时间函数测试力。手锤必须拥有一个测力传感器，安装在尖端与锤体之间。同样地，也可以在手锤上安装加速度计，以锤体的质量来获得力。力传感器的校准精度应在5%以内。手锤应设计合理，实测力在进行傅里叶变换后频域曲线应光滑，避免出现局部的峰值。5.2.3PlacementofTransducers—Themotionsensorshouldbeplacedatornearthepileheadusingasuitable,ortemporary,bondingmaterial(thatis,wax,vaseline,etc.)sothatitisassuredthatitcorrectlymeasurestheaxialpilemotion(transduceraxisofsensitivityalignedwiththepileaxis).Themotionsensorisplacedgenerallynearthecenterofthepile.Additionallocationsshouldbeconsideredforpileswithdiametersgreaterthan500mm.Thelowstrainimpactshouldbeappliedtothepileheadwithinadistanceof300mmfromthemotionsensor.Ifthepileheadisnotaccessible,aswhenalreadyintegralwiththestructure,thesensor(s)maybeattachedtothesideofthepileshaft.传感器的安装-传感器应使用一种合适的，临时性的，粘合材料（例如蜡、凡士林等）安装在桩顶，确保其可以准确测量桩身轴向运动（测试方向应与桩轴线一致）。加速度传感器通常安装在桩中心附近。当桩径大于500mm的桩，需要根据桩径不同,考虑增加不同位置的测试。激振点的位置一般距离传感器300mm5.3SignalTransmission—Thesignalsfromthesensorsshallbeconveyedtotheapparatusforrecording,reducing,anddisplayingthedata,see5.4,byalownoiseshieldedcableorequivalent.信号传输—来自传感器的信号，必须由低噪声屏蔽传输线或者等效物，传输至仪器，并以数据的形式记录、还原及显示，参见5.4。5.4ApparatusforRecording,ReducingandDisplayingData:仪器中数据的记录、还原及显示5.4.1General—Thesignalsfromthemotionandforce(optional)sensors,see5.2,shallbeconveyedtoanapparatusforrecording,reducing,anddisplayingdataasafunctionoftime.Theapparatusshallincludeagraphicdisplayofvelocityandforce(optional),andadatastoragecapabilityforretrievingrecordsforfurtheranalysis.Theapparatusshouldbecapableofaveragingdataofseveralblowstoreinforcetherepetitiveinformationfromsoilandpileeffectswhilereducingrandomnoiseeffects.Theapparatusshallbeabletoapplyincreasingintensityamplificationofthemotionsignalwithtimeaftertheimpacttoenhancetheinterpretationofthemeasuredmotionsthatarereducedbysoilandpilematerialdamping.Theapparatusmusthavefilteringcapabilitywithvariablefrequencylimitsforeliminatinghighfrequency,orlowfrequencysignalcomponents,orboth.Theapparatusshallbecapableoftransferringalldatatoapermanentstoragemedium.Theapparatusshallallowforapermanentgraphicaloutputoftherecords.AtypicalschematicarrangementforthisapparatusisillustratedinFig.2.概要—传感器获得的速度及力信号传输到仪器后（见5.2），应该以时间函数的数据形式被记录、还原并显示。仪器应具有一个显示器，以显示速度及力曲线，数据存储后应可以随时调出以供将来分析使用。仪器应具有将数锤信号叠加平均的功能，以提高信噪比，突出来自桩身及桩周土的有用信息，压制随机的噪声干扰。仪器应具有对时间信号进行指数放大的功能，补充因桩身及桩周土对桩身质点运动的阻尼衰减。仪器应具有限制各种频率的滤波功能，可以截止高频或低频波，或两者皆有。仪器应具有永久存储数据的功能。仪器应可以将记录以图形方式输出。典型桩的完整性检测设备组成，详见图2。FIG.2SchematicDiagramofApparatusforIntegrityTesting图2完整性检测仪器示意图5.4.2RecordingApparatus—Analogsignalsfromthemotionsensormustbedirectlydigitizedusingananalogtodigitalconvertorwithatleast12bitresolutionsuchthatsignalcomponentshavingalowpasscut-offfrequencyof15000Hz(−3dB)areretained.Whendigitizing,thesamplefrequency,therefore,shallbeatleast30000Hzeachforthemotionsensorandtheoptionalinstrumentedhammer,ifused.Theuniformityandaccuracyofthedigitalsamplingfrequencyiscritical;theclockjitter(samplingfrequencyaccuracy)mustbewithin0.01%.Analogdataacquisitionsystemsarespecificallyprohibited.Attachedtoeverydigitizedeventshouldbeidentifyinginformationnamesanddescriptions,signalprocessingenhancementparameters,anddateandtimestamps.记录仪—传感器产生的模拟信号必须直接被数字化，要求数-模转换精度至少大于16位，保留低通截止频率为15000Hz（-3dB）。在数字化时，采样频率，针对传感器或者选择使用的手锤，应该大于30000Hz。数字化采样频率的一致性及精度应严格保证。时钟偏差（采样频率的精度）应保证在0.01%以内。模拟数据获得系统是明确被禁止的。每个数字化后的数据都应附加上识别信息，如命名、描述、信号处理放大参数、日期及时间。5.4.3ApparatusforReducingData—Theapparatusforreducingsignalsfromthetransducersshallbeadigitalcomputerormicroprocessorcapableofatleastthefollowingfunctions:数据还原—仪器VelocityData—Ifaccelerometersareused(see5.2.2),theapparatusshallprovidesignalconditioningandcalibrationandintegrateaccelerationtoobtainvelocity.Theapparatusshallbalancethevelocitysignaltozerobetweenimpactevents.速度数据—如果采用加速度传感器（详见5.2.2），仪器应提供信号调节，校准及积分的功能，以得到速度。仪器应在多次激振的间隙，保持速度信号归零。ForceMeasurements—Theapparatusshallprovidesignalconditioning,amplification,andcalibrationfortheforcemeasurements.Theforceoutputshallbebalancedtozerobetweenimpactevents.力的测量—仪器应提供力信号的调节、放大及校准功能。力的输出，应在多次激振间隙保持信号归零。SignalConditioning—Thesignalconditioningforforceandvelocityshallhaveequalfrequencyresponsecurvestoavoidrelativephaseshiftsandamplitudedifferences.信号调节—仪器对速度及力信号的调节，应具有与原曲线相等的响应频率，应避免相关的相位偏移及振幅的失真。5.4.4DisplayApparatus—Ensurethatthesignalsfromthetransducersspecifiedin5.2.1and5.2.2aredisplayedbymeansofanapparatus,suchasanLCDgraphicdisplay,suchthatthevelocityandforce(optional)canbeobservedasafunctionoftimeforeachhammerblow.Thisapparatusmayreceivethesignalsaftertheyhavebeenprocessedbytheapparatusforreducingthedata.Theapparatusshalldisplaythedigitizeddataoftheimpacteventoruponrecallbytheuserofthedigitallystoredevent.Adjusttheapparatustoreproduceasignalhavingarangeofdurationbetween2msand30ms.Ensurethattheapparatusiscapableofdisplayingthesignalfromeachselectedblowforaminimumperiodof30s.显示设备—是指确保从传感器传输来的信号（如5.2.1及5.2.2所指）能被及时显示的设备，如液晶显示器，如此便能及时观察到每次激振下以时间为函数的速度及力曲线。仪器应能接受经还原及后处理完的数据。仪器应能显示每次激振后的数字信号，也能显示使用者从存储器中回放的数字信号。显示器应在持续2~30ms的时间范围内，可重新显示信号。确保在最短30s内，显示器应具有显示被选中的任意激振中每一锤信号的功能。6.Procedure测试过程6.1General—Recordapplicableprojectinformationintotheapparatuswhenappropriate(Section7).Attachtheappropriatemotionsensor(see5.2)tothepilehead,andrecordthemeasurementsfromseveralimpacts.Averagethesuitablerecordsofseveralimpactsandapplynecessaryamplificationtotheaveragedrecord.Therecordsfromtheindividualimpactsortheaveragedrecord,orboth,shouldthenbestored(see5.4.2).Theaveraged,amplifiedrecordthencanbeevaluatedforintegrity.概述—在适当的时间，将工程的有效信息记录在仪器中（参见第7部分）。将测振传感器安装在桩顶适当的位置，然后记录连续几次激振的测量结果。将几次有效激振测量结果平均，然后对平均后的曲线进行必要的放大处理。要求对每次激振的信号及平均后的信号，均应被仪器记录（详见5.4.2）。使用放大后的平均曲线对完整性进行评价。6.2Preparation—Forcast-in-placeconcretepilesorconcretefilledpipepiles,performtheintegritytestingnosoonerthan7daysaftercastingorafterconcretestrengthachievesatleast75%ofitsdesignstrength,whicheveroccursearlier.Ensurethatthepileheadsurfaceisaccessible,abovewater,andcleanoflooseconcrete,soilorotherforeignmaterialsresultingfromconstruction.Ifthepileheadiscontaminated,removeasufficientpilesectiontoreachsoundconcrete.Ifnecessary,preparesmallareasbyahandgrindertoprovideasmoothsurfaceformotionsensorattachmentandimpact.Attachthemotionsensorfirmlywithappropriatematerialatselectedlocationsawayfromtheedgeofthepilehead.Forpileswithdiameterslargerthan500mm,attachtheaccelerometerataminimumofthreelocationssothatanintegrityevaluationnearthepileheadmaybemadeforeachlocalizedsectionofpile.Positiontheapparatusforapplyingtheimpactforcesothattheimpactisappliedaxiallywiththepileandatadistancenolargerthan300mmfromtheaccelerometer.Setuptheapparatusforrecording,reducing,anddisplayingdatasothatitisoperationalandtheforceandvelocitysignalsarezeroed.准备工作—钻孔灌注桩或混凝土填充钢管桩的完整性检测，应在浇筑7天后或者达到设计强度的75%后进行，两者以先达到者为准。确保被测桩顶面适合测试，并位于水位以上，将松动混凝土、浮土及其他物质清理干净。如果桩顶混凝土质量低，应剔除直至坚实的桩身混凝土。如果必要，可以在桩顶用手砂轮打磨出一小片平整区域，用于粘贴传感器及激振。传感器应使用合适的材料牢固粘贴在远离桩顶边缘的区域。对于直径大于500mm基桩，至少应在桩顶3个不同的位置安装传感器分别进行检测，这样其完整评价也许就可能由每个局部检测结果组成。测力锤激振方向应与桩轴方向一致，作用点距离加速度传感器不大于300mm。设置好仪器的记录、还原及显示参数，使其处于操作状态，所有力及速度信号均归零。6.3FieldNotes—Includethefollowinginformationindetailedrecords,asavailable,foreachpiletested.现场注意事项—对于每根被测桩，下面列出了各项可能有用的需要记录的信息。6.3.1Pileidentification,nominalandactualpileheaddiameterandlength;桩型，正常的及实际的桩径和桩长；6.3.2Dateandmethodofconcreteplacement;混凝土浇筑的方式及时间；6.3.3As-builtgeometrythatis,totalconcretevolume,nominaloractualdiameterversuslength,permanentortemporarycasing,steelreinforcement,etc.;桩身的几何尺寸，如总体积，正常或实际的径长比，永久的或临时的护筒，钢筋，等等。6.3.4Soilstratigraphy;地层6.3.5Anyspecificobservationrelatedtoeachpiletestedthataffectsthepileconstruction,excavation,integrity,etc.;任何有可能影响基桩施工、开挖，完整性等等的特殊现象6.3.6Locationoftransducersatpileheadandcorrespondingmeasurements;and,传感器在桩顶安装的位置及相应的测量，以及6.3.7Datepileistested.已经测试的桩数量。6.4TakingMeasurements—Applyseveralimpactsandrecordeachindividualimpactortheaverage,ifrequired,orboth.Ifonlytheindividualimpactsarerecorded,ensurethattheapparatusforrecording,reducing,anddisplayingdataiscapableofaveragingupto10individualrecords.Recordthenumberofimpactsforaspecificaveragedrecord.Take,record,anddisplayaseriesofvelocityandforce(optional)measurements.测试—实施多次激振，记录每次激振信号，如果有必要，则应记录它们的平均信号。如果是单激振记录，确保仪器具有记录、还原及显示平均10个单激振数据的能力。仪器还应具有记录特殊数量激振的平均信号的功能。可以通过对信号的取得、记录及显示，来完成对一系列的速度和力（可选）的测量。6.5DataQualityChecks—Forconfirmationofdataquality,theoperatorshallmonitorthevelocityandforce(optional)fromseveralimpacteventsforconsistency.Ensurethattheapparatusforrecording,reducing,anddisplayingdataiscapableofdeterminingthemeasurementdeviceoverloadthreshold.Donotusetherecordsofimpactsthatcausethemeasurementdevicetooverload.Consistentrecordsaretheresultofuniformimpactsonsoundconcrete,transducersystemsthatareproperlyfunctioning,motionsensorsthatarefirmlyattached,andtheapparatusforrecording,reducing,anddisplayingdataproperlyfunctioning.Ifrecordsarenotrepeatable,donotusethedata.Ifthecauseofpoordataisnotamotionsensorattachmentproblembutratherisfoundtobeatransducermalfunction,repairorrecalibrateitbeforefurtheruse.数据质量的检查—操作者应该通过观察在相同位置几次激振下速度和力信号是否具有一致性，来判定信号的质量。确保记录、还原及显示的仪器具有判定测量设备是否超负荷的能力。不允许采用测量设备超负荷工作所采集的信号。标准的信号应该是，在新鲜混凝土桩顶测试，采用合理的激振，传感器系统工作正常，并稳固地粘贴在合理的位置，仪器的记录、还原及显示功能正常，上述情况下所采集的数据，应具有良好的一致性。不具有一致性的数据不得使用。如果发现在粘贴正常的情况下，传感器出现，应在修复或标定后再使用。NOTE1—Itisgenerallyrecommendedthatallcomponentsoftheapparatusforobtainingdynamicmeasurementsandtheapparatusforrecording,reducing,anddisplayingdatabecalibratedifanysignsofsystemmalfunctionsbecomeapparent.注1—如果信号出现任何不正常现象，一般建议对所有组成动力测试仪器的组成部分，及记录、还原及显示部分，均进行校准。6.6AnalysisofMeasurements测量结果的分析6.6.1WiththePulseEchoMethod(PEM),measuredpileheadvelocityisanalyzedasafunctionoftime.Often,thismethodgivessufficientinformationforintegrityevaluation.Alternately,thepileheadforcecanbemeasuredaswell.Thecombinationofforceandvelocitymaygiveadditionalinformationregardingthepileintegritynearthepilehead.TheTransientResponseMethod(TRM)requiresmeasurementofboththepileheadvelocityandforce.Forbothmethods,datamaybeevaluatedinbothtimedomainandfrequencydomain.针对反射波法（PEM），利用桩顶速度的时程曲线进行分析。通常，该方法已经包含了充足的桩的完整性信息。另外更好地，可以测量桩顶的激振力。将速度与力归一化，会得到桩顶附近有关桩身完整性额外的信息。瞬态响应法（TRM）要求测试桩顶的速度及力。两种方法，其数据都可以在时间域与频率域内评价。6.6.2Obtainvelocityandforce(optional)fromthereadoutoftheapparatusforreducingdata(see5.4.3)orfromthedisplayapparatus(see5.4.4).Inthetimedomainanalysis(PEM),basethepileintegrityevaluationonrelativeincreasesanddecreasesofvelocityaftertheinitialimpactpulse(Fig.3,Fig.4).Thedisplayeddatashouldincludethevelocityandforce(optional)recordswithtime,anindicationofthepilelengthandassumedmaterialwavespeedandarepresentationoftheshapeandmagnitudeoftheamplificationfunctionwhenused.Themotionduringtheimpacteventisnormalizedusuallyandisassociatedwiththepilehead.Theamplificationisusedgenerallytoscalethepiletoeresponsetoasimilarmagnitude.Apparentreflectionsoccurringpriortothetoeresponsethatareofthesamesignastheinputareduetoarelativedecreaseofimpedance.Reflectionsoftheoppositesignareduetoarelativeincreaseofimpedance.Comparisonofresultsfromseveralpilesfromthesitewithsimilarconstructionisrecommendedtoassessthetypicalresponsewiththesameamplificationfactorbeingappliedtoallpilesofsimilarlengths.Visualinterpretationmaybequalitativeandpossiblyrelativetoothertestedpilesandamatterofproperengineeringjudgment.可以从还原系统内读出速度及力的数据（详见5.4.3），也可以从显示系统中得到（详见5.4.4）。在时间域分析（PEM），是基于分析初始激振后，桩身完整性与速度曲线增大或减小的相关性来评价的（见Fig.3,Fig.4）.被显示的数据应该包括速度和力的时程曲线，能反映桩长及假定的波速，可以显示桩身的外形，以及可以使用指数放大功能。传感器在激振过程中保持正常工作，并与桩顶紧密联系在一起。指数放大通常应采用同一倍数，以测量桩底的响应。显然，在桩底反射前出现了与入射波相同的反射波，则表明在相关位置，桩身的波阻抗减小了。若出现与入射波相反的反射波，则表明相关位置桩身的波阻抗增加了。针对同一场地，同一设计桩型，同一施工方法，推荐对比多根基桩的测试结果，在桩长相同及指数放大倍数相同时，以得到具有代表性典型的响应曲线。形象的解释也许是定性的，与其他已测完桩有关的，也许是正确的工程判断。

FIG.3TypicalVelocityRecordIndicatingPileofGenerallyUniformNature(GradualImpedanceChangesorSoilFriction)图3表明桩身完整的典型速度记录（阻抗渐变或有土阻力）FIG.4TypicalVelocityRecordIndicatingMajorChangesinImpedance(SevereDamageoraCrackedPile)图4表明桩身有明显阻抗变化的典型速度记录（严重的损坏或断桩）6.6.3Therecordeddatamaybesubjectedtofurtheranalysisinacomputertoquantifybettertheextentofanapparentanomaly.Theresultsoftheanalysismayincludeaquantitativeassessmentofpileintegrity.Suchfurtheruseandinterpretationofthedataisamatterofengineeringjudgmentandexperience.出现显然异常的情况，数据也许应该更进一步由计算机进行定量化处理为好。评价结果可以包括定量的桩身完整性的分析。如此进一步分析的作用及解释，一般是工程上的判定及经验。6.6.4Engineerswithspecializedexperienceinthisfieldaretomakefinalintegrityevaluation.Useintegrityevaluationfromlowstrainteststogetherwithotherinformation,includingpileinstallationproceduresandobservations,soilinformation,loadingrequirements,etc.,toassessthepile’sacceptance.Thelowstrainintegrityevaluationshouldnotbeusedasthesolefactorinestablishingpileacceptanceorrejection.Acontingencyplanshouldbeformedthatallowstheengineertopossiblyperformfurthertestsordictatepilerepairorreplacementpriortotheintegritytesting,incaseaseriousdefectisindicated.在这个领域具有特殊经验的工程师，会对完整性做出最终的评价。应使用其他有效信息，与低应变测试一起进行桩身完整性评价，包括基桩施工程序及观测资料，地层资料，荷载要求等等，以评定桩身质量的可信度。在完整性测试前需要编制一个意外事件应对计划，当基桩出现严重的缺陷时，允许工程师可以进行进一步的测试，或者下令修补基桩或替换。6.6.5Certainlimitationsareinherentinlow-strainintegritytesting.Theselimitationsmustbeunderstoodandtakenintoconsiderationinmakingthefinalintegrityevaluation.Integrityevaluationofapilesectionbelowacrackthatcrossestheentirepilecross-sectionalareaoramanufacturedmechanicaljointisnotnormallypossiblesincetheimpactwavelikelywillreflectcompletelyatthediscontinuity.Pileswithhighlyvariablecrosssectionsormultiplediscontinuitiesmaybedifficulttoevaluate.Insomecases,itmaybedifficulttodistinguishthesoilresponsefromthepileresponse.Themethodisgenerallynotsuitablefortestingsteelsheet,H-sectionorunfilledpipepiles.Ifthereflectionfromthepiletoeisnotevidentintherecords,theintegrityevaluationmaynotbeconclusiveandmaybelimitedtoacertainunknowndepth.Thislimitationmayapplytolongorhighlyvariablepilesorpilesinsoilsthatexhibitrelativelyhighfriction.Pilesthatarerigidlyconnectedtoafootingorsuperstructurearesometimestestedsuccessfullyalthoughtheevaluationoftenmaybemoredifficultandmaybeinconclusive.Somecasesinvolvingintegralsuperstructuresmayrequireuseoftwomotionmeasuringdevicesattachedattwodifferentlocationsalongthepileshaft.低应变完整性测试具有一些不可克服的局限性。这些局限性需要被了解，以及在最终的完整性评价中予以考虑。位于桩身全断裂面以下，或者桩身机械连接面以下的桩身，由于激振波在此界面很可能将被完全反射回来，因此其完整性不能被正常判定。桩身若具有很多种截面或者许多断裂面，其完整性将很难被判定。在有些情况下，也很难将土阻力的响应从桩身阻抗响应中区分出来。该方法一般不适用于测试钢板桩，H型钢桩，或未填充完全的钢管桩。如果桩底反射无法判别，完整性评价也许将不确切，也许会受到桩长未知的限制。这种局限性也许会体现在长桩，阻抗变化多的桩，或者桩周土相对地展示出高摩擦力的桩的测试上。尽管评价经常也许会很困难，也许无法得到结论，当桩被很稳固地固定在地层中或结构上，有时的测试也会很成功的。有些情况下，基桩会位于上部结构中，可以沿着桩轴在桩身不同地方安装2个传感器进行测试。6.6.6Integritytestingmaynotidentifyallimperfections,butitcanbeausefultoolinidentifyingmajordefectswithintheeffectivelength.Also,thetestmayidentifyminorimpedancevariationsthatmaynotaffectthebearingcapacityofthepile.Forpileshavingminorimpedancevariations,theengineershouldusejudgementastotheacceptabilityofthesepilesconsideringotherfactorssuchasloadredistributiontoadjacentpiles,loadtransfertothesoilabovethedefect,appliedsafetyfactors,andstructuralloadrequirements.完整性测试不可能鉴别出桩身所有的缺陷，但可以在有效的长度范围内判定出主要的缺陷。同样，测试也可判别出对承载力不会产生影响的桩身阻抗的细小变化。对于桩身存在阻抗细小变化，工程师应该判断在考虑了其他因素后这些桩的可接受性，如邻近桩荷载的再分配，荷载转换致缺陷以上的桩周土上，实用的安全系数，以及结构荷载的要求。7.Report报告7.1Backgroundinformationanddescriptionshelpfultopileevaluationmayincludethefollowingwhenavailable,orapplicable,orboth:当需要时，下面所列的背景信息及描述对于评价是十分有帮助的7.1.1General概述Projectidentification/location;and,项目名称/地点；及Logofnearbyortypicaltestboring(s).原位勘探孔或附近的柱状图7.1.2PileInstallationEquipment—Descriptionofpileinstallationequipmentusedforeitherdrivingpilesordrillingpiles,asappropriateifrelatedtotheintegrityinvestigation,includingsize,type,operatingperformancelevelsorpressures,pumpsizes,andanyspecialinstallationequipmentandtheirdescriptionsuchasforpredrillingorjetting.桩施工设备—如果与完整性调查有关，适当地叙述成桩设备，无论是用于钻孔桩，还是打入式桩，包括尺寸，型号，操作性能水平及压力，泵的大小，7.1.3TestPiles测试桩Identification(nameanddesignation)oftestpile(s);测试桩的标识（名称及编号）Typeanddimensionsofpile(s)includingnominaloractuallengthanddiameter,orboth;类型及尺寸，设计桩长桩径或实际值，或都要；Datetestpilesmade,cast,orinstalledorconcretecylinderstrength,orboth;成桩日期，浇筑日期，或混凝土圆柱体试块强度，或都要Descriptionofinternalandexternalreinforcementusedintestpile(size,length,numberandarrangementoflongitudinalbars;casingorshellsizeandlength);描述用于测试桩内部或外部的钢筋（其尺寸，长度，数量，纵向筋的分布；保护层或外壳的尺寸及长度）Descriptionandlocation,whereapplicable,ofsplices;and,描述及位置，被利用于何处，接合位置，以及Observationsofpilesincludingspalledareas,cracks,andheadsurfacecondition.桩身外观观察，包括有碎片的范围，裂缝，及桩头表面的状态。7.1.4PileInstallationDateofinstallation;成桩日期Fordrilledshafts,includethesizeoftheauger,volumeofconcreteorgroutplacedinpile(volumeversusdepth,ifavailable),groutpressureused,andadescriptionofspecialinstallationproceduresused,suchaspilecasinginstallationorextraction,orboth;钻孔桩，包括钻具的尺寸，混凝土体积或者浇筑体积（每米体积，如有用），浇筑的泵压，以及特殊成桩过程的描述，如护筒的安置或拔除；Fordrivenpiles(whenthedrivingprocessisthesuspectcauseofdamage),includehammercushionandpilecushioninformation;includedrivingrecords,includingblowcountandhammerstrokeoroperatinglevelforfinalunitpenetration;打入式桩（当怀疑打桩过程损坏了桩身），包括锤垫；打桩记录；最后单位贯入度的锤击数或锤的工作水平Causeanddurationofinterruptionsinpileinstallation,ifapplicableandrelatedtotheinvestigation;and,如果与完整性有关，施工中停锤的原因及持续时间，以及Notationofanyunusualoccurrencesduringinstallationorexcavation,orboth,t