ASTM D4633-2010 Standard Test Method for Energy Measurement for Dynamic Penetrometers《动态透度计能量测量的标准试验方法》.pdf

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1、Designation: D4633 10Standard Test Method forEnergy Measurement for Dynamic Penetrometers1This standard is issued under the fixed designation D4633; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe

2、r in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method describes procedures for measuring theenergy that enters the penetrometer drill rod string duringdynamic penetrometer testi

3、ng of soil due to the hammerimpact.1.2 This test has particular application to the comparativeevaluation of N-values obtained from the Standard PenetrationTests (SPT) of soils in an open hole as in Test Method D1586and Practice D6066. This procedure may also be applicable toother dynamic penetromete

4、r tests.1.3 The values stated in SI units are to be regarded asstandard. The inch-pound units given in parentheses aremathematical conversions which are provided for informationpurposes only and are not considered standard.1.4 LimitationsThis test method applies to penetrometersdriven from above the

5、 ground surface. It is not intended for usewith down-hole hammers.1.5 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.6 The method used to specify how data are collected,calculated, or recorded in this standard is n

6、ot directly related tohow the data can be applied in design or other uses, since thatis beyond its scope. Practice D6066 specifies how these datamay be normalized.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the

7、user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1586 Test Method for Penetration Test (SPT) and Split-Barrel Sampling of SoilsD3740 Practice for Minimum Req

8、uirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD6026 Practice for Using Significant Digits in GeotechnicalDataD6066 Practice for Determining the Normalized Penetra-tion Resistance of Sands for Evaluation of LiquefactionPotenti

9、al3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 acceleration transducer, or accelerometerinstrument attached on, around, or within a continuous columnof drill rods to measure the time-varying acceleration generatedin the drill rods by the impact of the hammer.3.1.2 anvilthe

10、mass at the top of the drill rods that isstruck by the hammer.3.1.3 drill rodsthe steel rods connecting the hammersystem above the ground surface to the sampler below thesurface.3.1.4 force transducera section of drill rod instrumentedwith strain gages and inserted into the continuous column ofdrill

11、 rods to measure the time-varying force generated in thedrill rods by the impact of the hammer.3.1.5 hammeran impact mass that is raised and droppedto create an impact on the drill rods.3.1.6 impedance (of the drill rod)a property of the drillrod equal to the drill rod elastic modulus times the cros

12、ssectional area divided by the velocity of wave propagation.3.1.7 instrumented subassemblya short section of drill rodinstrumented to measure force and acceleration which isinserted at the top of the drill rod and below the anvil.3.1.8 penetrometerany sampler, cone, blade, or otherinstrument placed

13、at the bottom of the drill rods.3.2 Symbols:EFV = the energy transmitted to the drill rod from thehammer during the impact event (see 7.10).ETR = (EFV / PE) ratio of the measured energy transferredto the drill rods to the theoretical potential energy.1This test method is under the jurisdiction ofAST

14、M Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.02 on Sampling andRelated Field Testing for Soil Evaluations.Current edition approved Jan. 1, 2010. Published February 2010. Originallyapproved in 2005. Last previous edition approved in 2005 as D4633 05. DOI:10.152

15、0/D4633-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Dri

16、ve, PO Box C700, West Conshohocken, PA 19428-2959, United States.L = length between the location of transducers on the instru-mented subassembly and the bottom of the penetrometer.2L/c = the time required for the stress wave (traveling at aknown wave speed, c, in steel of 5123 m/s (16 810 ft/s) totr

17、avel from the measurement location to the bottom of thepenetrometer and return to the measurement location.N-value = the number of hammer blows required to advancethe sampler the last 0.305 m (1.00 ft) of the 0.457 m (1.5 ft)driven during an SPT test.PE = the theoretical potential energy of the hamm

18、er posi-tioned at the specified height above the impact surface.4. Significance and Use4.1 Various driven in situ penetrometers are used to evaluatethe engineering behavior of soils. The Standard PenetrationTest is the most common type. Engineering properties can beestimated on the basis of empirica

19、l correlations betweenN-values and soil density, strength or stiffness. Alternatively,the N-value can be used directly in foundation design usingcorrelations to design parameters such as allowable bearingpressure or pile capacity. The N-value depends on the soilproperties but also on the mass, geome

20、try, stroke, anvil, andoperating efficiency of the hammer. This energy measurementprocedure can evaluate variations of N-value resulting fromdifferences in the hammer system. See also Refs (1-6).34.2 There is an approximate, linear relationship between theincremental penetration of a penetrometer an

21、d the energy fromthe hammer that enters the drill rods, and therefore anapproximate inverse relationship between the N-value and theenergy delivered to the drill rods.NOTE 1Since the measured energy includes the extra potential energyeffect due to the set per blow, tests for energy evaluation of the

22、 hammersystems should be limited to moderate N-value ranges between 10 and 50(Ref (7).4.3 Stress wave energy measurements on penetrometersmay evaluate both operator-dependent cathead and rope ham-mer systems and relatively operator-independent automaticsystems.4.4 The energy measurement has direct a

23、pplication forliquefaction evaluation for sands as referenced in PracticeD6066.4.5 This test method is useful for comparing the N-valuesproduced by different equipment or operators performing SPTtesting at the same site, aiding the design of penetrometersystems, training of dynamic penetrometer syst

24、em operators,and developing conversion factors between different types ofdynamic penetration tests.NOTE 2The quality of the result produced by this standard isdependent on the competence of the personnel performing it, and thesuitability of the equipment and facilities used. Agencies that meet thecr

25、iteria of Practice D3740 are generally considered capable of competentand objective testing and inspection. Users of this standard are cautionedthat compliance with Practice D3740 does not in itself assure reliableresults. Reliable results depend on many factors: Practice D3740 providesa means of ev

26、aluating some of those factors.5. Apparatus5.1 Apparatus for MeasurementAn instrumented subas-sembly defined in 3.1.7 shall be inserted at the top of the drillrod string directly below the hammer and anvil system so thatthe hammer impact is transmitted through the anvil into theinstrumented subassem

27、bly and then into the drill rods. Thesubassembly shall be made of steel drill rod and shall be atleast 0.60 m (2 ft) in length. The measurement location of forceand acceleration shall be located at least 0.30 m (1 ft) below thetop of the instrumented subassembly, and shall be at least threediameters

28、 away from any cross sectional area change.NOTE 3While having the same nominal area for the instrumentedsubsection as the drill string is desirable, variations in area are unavoid-able since (a) the drill rods wear, (b) drill rod manufacture tolerance ofwall thickness is rather loose, (c) joints alr

29、eady impose significant crosssection changes far larger than the variation of cross section changesfound among common drill rod types (for example, AW, BW, NW or N3),and (d) many drillers have and therefore mix both heavy and light sectionrods, particularly of the NW type), making it practically imp

30、ossible tomeasure with identical cross sections.5.2 Apparatus to Measure ForceThe force in the drillrods shall be measured by instrumenting the subassembly withfoil strain gages in a full bridge circuit. The gages shall bearranged symmetrically such that all bending effects arecanceled. The instrume

31、nted rod section shall have a minimumof two such full bridge circuits. Transducer systems that insertmassive elements or load cells with stiffness properties sub-stantially different than those of the rods themselves arespecifically prohibited.5.3 Apparatus to Measure AccelerationAcceleration datash

32、all be obtained with a minimum of two accelerometersattached on diametrically opposite sides of the drill rod within100 mm (4 in.) of the force measurement location. Theaccelerometers shall be aligned axially with the rod in theirsensitive direction and shall be bolted, glued, or welded to therod wi

33、th small rigid (solid, nearly cubic shape) metal mounts.Overhanging brackets that can bend during impact and plasticmounting blocks are prohibited. Accelerometers shall be linearto at least 10 000 g and have a useable frequency response toat least 4.5 kHz.NOTE 4The rigidity of the accelerometer moun

34、ting block can beassessed by comparing the rise times of the velocity to the force signal.5.4 Apparatus for Recording, Processing and DisplayingData:5.4.1 GeneralThe force and acceleration signals from thehammer impact shall be transmitted to an instrument forrecording, processing, and displaying da

35、ta to allow determina-tion of the force and velocity versus time. The apparatus shallprovide power and signal conditioning for all transducers.There are two forms of data acquisition systems. Analogsystems electronically integrate measured acceleration to ve-locity through electronic circuitry and d

36、igitize the resultingvelocity. Digital systems acquire acceleration data and digitallyintegrate acceleration to velocity.5.4.2 Analog SystemsThe signal conditioning systemshall apply a low-pass filter to both force and velocity with acutoff frequency of 2 kHz or higher (preferably 5 kHz). Dataacquis

37、ition sampling rate shall be at least 5 times the low-pass3The boldface numbers in parentheses refer to the list of references at the end ofthis standard.D4633 102filter frequency to avoid signal aliasing. Automatic balancingmust be turned off during the impact event.5.4.3 Digital SystemsThe signal

38、conditioning shall applya low-pass filter to both force and acceleration with a cutofffrequency of 5 kHz or higher (preferably 25 kHz) (Ref (8). Toavoid aliasing, data acquisition sampling rate shall be at least10 times the low-pass filter frequency for single sampling ofeach data point, or at least

39、 5 times the low-pass filter frequencyfor analog to digital convertors with oversampling if theoversampling rate is at least 256 times the retained samplingrate.5.4.4 Apparatus for RecordingThe apparatus shall sampleeach signal and record the magnitude versus time of eachsensor in digital form with

40、a minimum 12-bit resolution. Thesignals from individual transducers for each blow shall bepermanently stored in digital form for a minimum time sampleso that the motion has ceased, or 50 milliseconds, whichever islonger. The zero line of the acceleration shall be determinedsuch that the velocity nea

41、r the end of the sample shall be zero.5.4.5 Apparatus for ProcessingThe apparatus for process-ing the data shall be a digital computer or microprocessorcapable of analyzing all data and computing results. Themeasured acceleration shall be integrated to obtain velocity.Small time shifts between the f

42、orce and velocity should beeliminated by time shifting one signal versus the other toaccount for small phase shifts up to at most 0.1 milliseconds.Larger time shifts indicate deficiencies in the measurementsystem and should be corrected.5.4.6 Apparatus for Data DisplayThe apparatus shalldisplay the

43、force and velocity signals graphically as a functionof time. The apparatus shall be capable of reviewing eachindividual measured signal to confirm data quality duringacquisition as described in 7.8. The apparatus for display shalldisplay the 2L/c time and the calculated energy result (see7.10).6. Ca

44、libration6.1 Force TransducerThe instrumented subassemblyshall be calibrated both in force and strain, each to an accuracywithin 62 %, The subassembly shall be loaded to at least 70 %of the anticipated force. The strain calibration allows directcomparison of strain with particle velocity. The dual c

45、alibrationallows determination of the calculated effective rod cross-sectional area, Ac, of the instrumented subassembly fromAc=(F/E) where F is the applied measured force, E is themodulus of steel of 206 000 MPa (29 900 ksi), and is themeasured strain at applied force F. If the calculated andmeasur

46、ed rod areas at the transducer section differ by morethan 5 percent, then the rod should be re-calibrated, or the areare-measured. If differences persist, the calculated area isconsidered more accurate.6.2 Accelerometer CalibrationThe accelerometer shall becalibrated to an accuracy within 63 % with

47、a shock of at least2000 gs using a Hopkinsons Bar with a steel to steel impact.The accelerometers shall be attached to the instrumentedHopkinsons Bar measuring strain, and the measured velocityfrom integration of acceleration compared with the measuredstrain which is theoretically proportional to ve

48、locity to checkthe acceleration calibration factor. The Hopkinsons Bar shallbe steel and be at least 10 m (33 ft) long with no welds orjoints. The impacting bar shall also be steel, of the same areaas the Hopkinsons Bar, and between 3 and 6 m (10 and 20 ft)long.6.3 Frequency of CalibrationCalibrate

49、force and accel-eration transducers at regular time periods or at frequency ofuse as required in the quality assurance plan for the company,project, or as recommended by the manufacturer, or every threeyears whichever is least.7. Procedure7.1 Observe the penetrometer testing in progress for apreparatory sequences of blows prior to energy measurement.Determine and record information, including drill rig type andserial number; hammer type and serial number; when appli-cable, a description of the cathead system (for example,number of rope turns, dr