1、Designation: D 4633 05Standard Test Method forEnergy Measurement for Dynamic Penetrometers1This standard is issued under the fixed designation D 4633; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A num
2、ber in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 te
3、sting 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 D 1586and Practice D 6066. This procedure may also be applicable toother dynamic penetr
4、ometer tests.1.3 LimitationsThis test method applies to penetrometersdriven from above the ground surface. It is not intended for usewith down-hole hammers.1.4 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D 6026.1.5 The
5、method used to specify how data are collected,calculated, or recorded in this standard is not directly related tohow the data can be applied in design or other uses, since thatis beyond its scope. Practice D 6066 specifies how these datamay be normalized.1.6 This standard does not purport to address
6、 all of thesafety concerns, if any, associated with its use. It is theresponsibility of the 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:2D 1586 Test Metho
7、d for Penetration Test and Split-BarrelSampling of SoilsD 3740 Practice for Minimum Requirements for AgenciesEngaged in the Testing and/or Inspection of Soil and Rockas Used in Engineering Design and ConstructionD 6026 Practice for Using Significant Digits in Calculatingand Reporting Geotechnical Te
8、st DataD 6066 Practice for Determining the Normalized Penetra-tion Resistance of Sands for Evaluation of LiquefactionPotential3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 acceleration transducer, or accelerometerinstrument attached on, around, or within a continuous columno
9、f drill rods to measure the time-varying acceleration generatedin the drill rods by the impact of the hammer.3.1.2 anvilthe 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 thesurfac
10、e.3.1.4 force transducera section of drill rod instrumentedwith strain gages and inserted into the continuous column ofdrill 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 d
11、rill rods.3.1.6 impedance (of the drill rod)a property of the drillrod equal to the drill rod elastic modulus times the crosssectional area divided by the velocity of wave propagation.3.1.7 instrumented subassemblya short section of drill rodinstrumented to measure force and acceleration which isins
12、erted at the top of the drill rod and below the anvil.3.1.8 penetrometerany sampler, cone, blade, or otherinstrument placed 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 measur
13、ed energy transferredto the drill rods to the theoretical potential energy.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) to trav
14、el from themeasurement location to the bottom of the penetrometer andreturn to the measurement location.1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.02 on Sampling andRelated Field Testing for Soil Evaluations.C
15、urrent edition approved Nov. 1, 2005. Published November 2005.2For 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
16、.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.N-value = the number of hammer blows required to advancethe sampler the last 12 in. (0.3 m) of the 18 in. (0.45 m) drivenduring an SPT test.PE = the theoretical potential energy of the
17、 hammer 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 emp
18、irical 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,
19、geometry, 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 penetromet
20、er and 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 o
21、f the hammersystems should be limited to moderate N-value ranges between 5 and 50.4.3 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 appli
22、cation forliquefaction evaluation for sands as referenced in PracticeD 6066.4.5 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 system
23、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 thecrite
24、ria of Practice D 3740 are generally considered capable of competentand objective testing and inspection. Users of this standard are cautionedthat compliance with Practice D 3740 does not in itself assure reliableresults. Reliable results depend on many factors: Practice D 3740 providesa means of ev
25、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
26、bly and then into the drill rods. Thesubassembly shall be made from the same type of drill rod asused in the drill rod string, shall be at least 600 mm (2 ft) inlength. The measurement location shall be located at least 300mm (1 ft) below the top of the instrumented subassembly, andshall be at least
27、 three diameters away from any cross sectionalarea change.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. Th
28、e instrumented 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 AccelerationAccelerat
29、ion datashall 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
30、 therod with 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 3The rigidity of the accelero
31、meter mounting 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 dis
32、playing data 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 circu
33、itry and digitize 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).
34、Dataacquisition sampling rate shall be at least 5 times the low-passfilter frequency to avoid signal aliasing. For analog integration,automatic balancing must be turned off during the impactevent.5.4.3 Digital SystemsThe signal conditioning shall applya low-pass filter to both force and acceleration
35、 with a cutofffrequency of 5 kHz or higher (preferably 25 kHz). Dataacquisition sampling rate shall be at least 10 times the low-passfilter frequency to avoid signal aliasing.5.4.4 Apparatus for RecordingThe apparatus shall sampleeach signal and record the magnitude versus time of eachsensor in digi
36、tal form with 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 is3The boldface numbers in parentheses refer to the list of references at t
37、he end ofthis standard.D4633052longer. The zero line of the acceleration shall be determinedsuch that the velocity near 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
38、and computing results. Themeasured acceleration shall be integrated to obtain velocity.Small time shifts between the force 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 deficie
39、ncies in the measurementsystem and should be corrected.5.4.6 Apparatus for Data DisplayThe apparatus shalldisplay the 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 d
40、escribed in 7.8. The apparatus for display shalldisplay the 2L/c time and the calculated energy result.6. Calibration6.1 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 an
41、ticipated force. The strain calibration allows directcomparison of strain with particle velocity. The dual calibrationallows determination of the calculated effective rod cross-sectional area, Ac, of the instrumented subassembly fromAc=(F/Ee) where F is the applied measured force, E is themodulus of
42、 steel of 206 000 MPa (30 000 ksi), and e is themeasured strain at applied force F. If the calculated andmeasured 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 m
43、ore accurate.6.2 Accelerometer CalibrationThe accelerometer shall becalibrated to an accuracy within 63 % with 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 velo
44、cityfrom integration of acceleration compared with the measuredstrain which is theoretically proportional to velocity to checkthe acceleration calibration factor. The Hopkinsons Bar shallbe steel and be at least 10 m long with no welds or joints. Theimpacting bar shall also be steel, of the same are
45、a as theHopkinsons Bar, and between 3 and 6 m long.6.3 Frequency of CalibrationCalibrate 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 whi
46、chever 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, (cathead:number of turns, drop height, rope over or
47、under the cathead,rope condition, crown sheave arrangement, for safety hammersnote guide rod size and if hollow or solid) (automatic: tripsystem, drop height, blow rate). Note any significant hammeroperating conditions such as weather, verticality, or changes inlubrication. Record drill rod dimensio
48、ns, including outside andinside diameters, section lengths, and type of connectors. Donot combine drill rods of varying sizes (for example, AW withNW).NOTE 4The number, size, and condition of pulley sheaves affects theenergy transfer. Energy is consumed in the friction and rotation of thesheave and
49、thus they should be inspected and their number and conditionnoted. Verticality may affect the drop system; align the penetrometersystem as close to vertical as possible. Because some automatic hammersare rate dependent, determine the hammer manufacturers proper operat-ing rate. If the rate is different, recommend hammer maintenance. Weatherconditions can affect rope and cathead operations.NOTE 5Preparatory sequences of blows have the objective of bring-ing the equipment and operator to their normal functioning condition. Theinitial blows can be used to
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