ASTM D4633-16

Standard Test Method for Energy Measurement for Dynamic Penetrometers

SIGNIFICANCE AND USE
4.1 Various driven in situ penetrometers are used to evaluate the engineering behavior of soils. The Standard Penetration Test is the most common type. Engineering properties can be estimated on the basis of empirical correlations between N-values and soil density, strength or stiffness. Alternatively, the N-value can be used directly in foundation design using correlations to design parameters such as allowable bearing pressure or pile capacity. The N-value depends on the soil properties but also on the mass, geometry, stroke, anvil, and operating efficiency of the hammer. This energy measurement procedure can evaluate variations of N-value resulting from differences in the hammer system. See also Refs (1-6).3  
4.2 There is an approximate, linear relationship between the incremental penetration of a penetrometer and the energy from the hammer that enters the drill rods, and therefore an approximate inverse relationship between the N-value and the energy delivered to the drill rods.
Note 1: Since the measured energy includes the extra potential energy effect due to the set per blow, tests for energy evaluation of the hammer systems should be limited to moderate N-value ranges between 10 and 50 (Ref (7)).  
4.3 Stress wave energy measurements on penetrometers may evaluate both operator-dependent cathead and rope hammer systems and relatively operator-independent automatic systems.  
4.4 The energy measurement has direct application for liquefaction evaluation for sands as referenced in Practice D6066.  
4.5 This test method is useful for comparing the N-values produced by different equipment or operators performing SPT testing at the same site, aiding the design of penetrometer systems, training of dynamic penetrometer system operators, and developing conversion factors between different types of dynamic penetration tests.
Note 2: The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitab...
SCOPE
1.1 This test method describes procedures for measuring the energy that enters the penetrometer drill rod string during dynamic penetrometer testing of soil due to the hammer impact.  
1.2 This test has particular application to the comparative evaluation of N-values obtained from the Standard Penetration Tests (SPT) of soils in an open hole as in Test Method D1586 and Practice D6066. This procedure may also be applicable to other dynamic penetrometer tests.  
1.3 The values stated in SI units are to be regarded as standard. The inch-pound units given in parentheses are mathematical conversions which are provided for information purposes only and are not considered standard. Reporting of test results in units other than SI shall not be regarded as nonconformance with this test method.  
1.3.1 The converted inch-pound units use the gravitational system of units. In this system, the pound (lbf) represents a unit of force (weight), while the unit for mass is slugs. The converted slug unit is not given, unless dynamic (F = ma) calculations are involved.  
1.4 Limitations—This test method applies to penetrometers driven from above the ground surface. It is not intended for use with down-hole hammers.  
1.5 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.  
1.5.1 The procedures used to specify how data are collected/recorded or calculated, in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user's objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard to consider significa...

General Information

• Status: Published
• Publication Date: 30-Jun-2016
• ICS: 93.020 - Earthworks. Excavations. Foundation construction. Underground works
• Technical Committee: D18 - Soil and Rock
• Drafting Committee: D18.02 - Sampling and Related Field Testing for Soil Evaluations

Relations

• Replaces: ASTM D4633-10 - Standard Test Method for Energy Measurement for Dynamic Penetrometers
• Effective Date: 01-Jul-2016
• Refers: ASTM D3740-23 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Nov-2023
• Refers: ASTM D3740-19 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Oct-2019
• Refers: ASTM D653-14 - Standard Terminology Relating to Soil, Rock, and Contained Fluids
• Effective Date: 01-Aug-2014
• Refers: ASTM D3740-12a - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-May-2012
• Refers: ASTM D3740-12 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Mar-2012
• Refers: ASTM D6066-11 - Standard Practice for Determining the Normalized Penetration Resistance of Sands for Evaluation of Liquefaction Potential (Withdrawn 2020)
• Effective Date: 01-Dec-2011
• Refers: ASTM D1586-11 - Standard Test Method for Standard Penetration Test (SPT) and Split-Barrel Sampling of Soils
• Effective Date: 01-Nov-2011
• Refers: ASTM D3740-11 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Sep-2011
• Refers: ASTM D653-11 - Standard Terminology Relating to Soil, Rock, and Contained Fluids
• Effective Date: 01-Sep-2011
• Refers: ASTM D3740-10 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Mar-2010
• Refers: ASTM D653-09 - Standard Terminology Relating to Soil, Rock, and Contained Fluids
• Effective Date: 01-Jan-2009
• Refers: ASTM D653-08a - Standard Terminology Relating to Soil, Rock, and Contained Fluids
• Effective Date: 01-Dec-2008
• Refers: ASTM D653-08 - Standard Terminology Relating to Soil, Rock, and Contained Fluids
• Effective Date: 01-Nov-2008
• Refers: ASTM D1586-08a - Standard Test Method for Standard Penetration Test (SPT) and Split-Barrel Sampling of Soils
• Effective Date: 01-Oct-2008

Overview

ASTM D4633-16: Standard Test Method for Energy Measurement for Dynamic Penetrometers provides procedures for accurately measuring the energy imparted to a penetrometer drill rod string during dynamic soil penetration tests. These tests are integral to the evaluation of soil engineering properties, commonly using the Standard Penetration Test (SPT). Variations in energy transfer from the hammer system can significantly impact the N-value, which is a critical parameter in geotechnical investigations for estimating soil density, strength, and stiffness.

Using precise energy measurement methods helps normalize N-values, supporting more reliable soil characterization and foundation design. This standard primarily targets comparative energy measurement during SPTs and is also applicable to other dynamic penetrometer tests performed above the ground surface.

Key Topics

• Energy Transfer Measurement: The standard defines procedures for measuring the energy transferred to the drill rods from the hammer, an essential factor influencing SPT N-values.
• Instrumentation: Establishes requirements for instrumented subassemblies, force transducers, and accelerometers to ensure accurate and repeatable measurements.
• Data Recording and Processing: Outlines protocols for data acquisition, digital processing of force and velocity signals, and calculation of key parameters such as EFV (energy transferred) and ETR (energy transfer ratio).
• Calibration: Specifies calibration intervals and methods for force and acceleration sensors to maintain measurement accuracy.
• Significance of N-value: Explains the relationships between measured energy, incremental penetrometer penetration, and N-values, including the importance of standardizing these values for design purposes.
• Operator and Equipment Variation: Addresses how energy measurements help evaluate differences between operators, hammer types (manual and automatic), and equipment setup.

Applications

ASTM D4633-16 is vital for geotechnical engineers, soil testing laboratories, and civil engineering contractors involved in site characterization and foundation design. Its primary applications include:

• Standard Penetration Testing (SPT): Ensuring that N-values from SPTs are properly normalized for accurate comparison and use in empirical design correlations.
• Equipment Comparison: Comparing N-values and energy transfer efficiency between different hammer systems or operators, enhancing the reliability of results across projects and teams.
• Foundation Design: Supporting the direct use of standardized N-values in the assessment of allowable bearing capacity, pile design, and ground improvement strategies.
• Liquefaction Evaluation: Providing normalized penetration resistance data for sands, crucial for assessing liquefaction potential in accordance with related standards.
• Training and QA/QC: Facilitating training of field personnel and ensuring quality assurance in dynamic penetrometer operations by monitoring energy transfer consistency.

Related Standards

To ensure comprehensive and standardized geotechnical testing, ASTM D4633-16 is often used in conjunction with the following standards:

• ASTM D1586: Test Method for Penetration Test (SPT) and Split-Barrel Sampling of Soils
• ASTM D6066: Practice for Determining the Normalized Penetration Resistance of Sands for Evaluation of Liquefaction Potential
• ASTM D653: Terminology Relating to Soil, Rock, and Contained Fluids
• ASTM D3740: Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• ASTM D6026: Practice for Using Significant Digits in Geotechnical Data

Using ASTM D4633-16 in tandem with these standards ensures consistent, reliable, and interpretable results across geotechnical investigations, supporting safer and more effective civil engineering designs.

---

Keywords: ASTM D4633-16, dynamic penetrometer, energy measurement, Standard Penetration Test, SPT N-value, geotechnical investigation, soil testing, foundation design, energy transfer, SPT hammer calibration, liquefaction analysis, force transducer, accelerometer, EFV, ETR, soil engineering properties.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D4633 − 16
Standard Test Method for
Energy Measurement for Dynamic Penetrometers
This standard is issued under the fixed designation D4633; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* of this standard to consider significant digits used in analytical
methods for engineering design.
1.1 Thistestmethoddescribesproceduresformeasuringthe
energy that enters the penetrometer drill rod string during 1.6 The text of this standard references notes and footnotes
dynamic penetrometer testing of soil due to the hammer which provide explanatory material.These notes and footnotes
impact. (excluding those in tables and figures) shall not be considered
as requirements of the standard.
1.2 This test has particular application to the comparative
1.7 This standard does not purport to address all of the
evaluation of N-values obtained from the Standard Penetration
safety concerns, if any, associated with its use. It is the
Tests (SPT) of soils in an open hole as in Test Method D1586
responsibility of the user of this standard to establish appro-
and Practice D6066. This procedure may also be applicable to
priate safety and health practices and determine the applica-
other dynamic penetrometer tests.
bility of regulatory limitations prior to use.
1.3 The values stated in SI units are to be regarded as
standard. The inch-pound units given in parentheses are
2. Referenced Documents
mathematical conversions which are provided for information
2.1 ASTM Standards:
purposes only and are not considered standard. Reporting of
D653 Terminology Relating to Soil, Rock, and Contained
test results in units other than SI shall not be regarded as
Fluids
nonconformance with this test method.
D1586 Test Method for Penetration Test (SPT) and Split-
1.3.1 The converted inch-pound units use the gravitational
Barrel Sampling of Soils
systemofunits.Inthissystem,thepound(lbf)representsaunit
D3740 Practice for Minimum Requirements for Agencies
of force (weight), while the unit for mass is slugs. The
Engaged in Testing and/or Inspection of Soil and Rock as
converted slug unit is not given, unless dynamic (F = ma)
Used in Engineering Design and Construction
calculations are involved.
D6026 Practice for Using Significant Digits in Geotechnical
1.4 Limitations—This test method applies to penetrometers
Data
drivenfromabovethegroundsurface.Itisnotintendedforuse
D6066 Practice for Determining the Normalized Penetration
with down-hole hammers.
Resistance of Sands for Evaluation of Liquefaction Poten-
1.5 All observed and calculated values shall conform to the
tial
guidelines for significant digits and rounding established in
Practice D6026.
3. Terminology
1.5.1 Theproceduresusedtospecifyhowdataarecollected/
3.1 Definitions:
recorded or calculated, in this standard are regarded as the
3.1.1 Fordefinitionsofcommontechnicaltermsusedinthis
industry standard. In addition, they are representative of the
standard, refer to Terminology D653.
significant digits that generally should be retained. The proce-
3.2 Definitions of Terms Specific to This Standard:
dures used do not consider material variation, purpose for
3.2.1 anvil, n—the mass at the top of the drill rods that is
obtaining the data, special purpose studies, or any consider-
struck by the hammer.
ations for the user’s objectives; and it is common practice to
increase or reduce significant digits of reported data to be
3.2.2 drill rods, n—the steel rods connecting the hammer
commensuratewiththeseconsiderations.Itisbeyondthescope
system above the ground surface to the sampler below the
surface.
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
Rock and is the direct responsibility of Subcommittee D18.02 on Sampling and
Related Field Testing for Soil Evaluations. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Currentedition approvedJuly 1,2016.PublishedJuly 2016.Originallyapproved contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
in 2005. Last previous edition approved in 2010 as D4633 – 10. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
D4633-16. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4633 − 16
3.2.3 hammer, n—an impact mass that is raised and dropped 4.3 Stress wave energy measurements on penetrometers
to create an impact on the drill rods. may evaluate both operator-dependent cathead and rope ham-
mer systems and relatively operator-independent automatic
3.2.4 impedance (of the drill rod), n—a property of the drill
systems.
rod equal to the drill rod elastic modulus times the cross
sectional area divided by the velocity of wave propagation.
4.4 The energy measurement has direct application for
liquefaction evaluation for sands as referenced in Practice
3.2.5 instrumented subassembly, n—a short section of drill
D6066.
rod instrumented to measure force and acceleration which is
inserted at the top of the drill rod and below the anvil.
4.5 This test method is useful for comparing the N-values
3.2.6 penetrometer, n—any sampler, cone, blade, or other
produced by different equipment or operators performing SPT
instrument placed at the bottom of the drill rods.
testing at the same site, aiding the design of penetrometer
systems, training of dynamic penetrometer system operators,
3.3 Symbols:
and developing conversion factors between different types of
3.3.1 EFV—the energy transmitted to the drill rod from the
dynamic penetration tests.
hammer during the impact event (see 8.1).
NOTE 2—The quality of the result produced by this standard is
3.3.2 ETR—(EFV / PE) – ratio of the measured energy
dependent on the competence of the personnel performing it, and the
transferred to the drill rods to the theoretical potential energy.
suitability of the equipment and facilities used. Agencies that meet the
criteria of Practice D3740 are generally considered capable of competent
3.3.3 L—length between the location of transducers on the
and objective testing/sampling/inspection/etc. Users of this standard are
instrumented subassembly and the bottom of the penetrometer.
cautioned that compliance with Practice D3740 does not in itself assure
reliable results. Reliable results depend on many factors: Practice D3740
3.3.4 2L/c—the time required for the stress wave (traveling
provides a means of evaluating some of those factors.
at a known wave speed, c, in steel of 5123 m/s (16 810 ft/s)) to
travel from the measurement location to the bottom of the
5. Apparatus
penetrometer and return to the measurement location.
5.1 Apparatus for Measurement—An instrumented subas-
3.3.5 N —standard penetration resistance adjusted to a 60
sembly defined in 3.2.5 shall be inserted at the top of the drill
% drill rod energy transfer ratio.
rod string directly below the hammer and anvil system so that
3.3.6 N-value—the number of hammer blows required to
the hammer impact is transmitted through the anvil into the
advance the sampler the last 0.305 m (1.00 ft) of the 0.457 m
instrumented subassembly and then into the drill rods. The
(1.5 ft) driven during an SPT test.
subassembly shall be made of steel drill rod and shall be at
3.3.7 PE—the theoretical potential energy of the hammer
least 0.60 m (2 ft) in length. The location of the strain gauges
positioned at the specified height above the impact surface.
and accelerometers shall be at least 0.30 m (1 ft) below the top
of the instrumented subassembly, and shall be at least three
4. Significance and Use
diameters away from any cross sectional area change.
4.1 Variousdriveninsitupenetrometersareusedtoevaluate
NOTE 3—While having the same nominal area for the instrumented
the engineering behavior of soils. The Standard Penetration
subassembly as the drill string is desirable, variations in area are
Test is the most common type. Engineering properties can be
unavoidable since (a) the drill rods wear, (b) drill rod manufacture
tolerance of wall thickness is rather loose, (c) joints already impose
estimated on the basis of empirical correlations between
significant cross section changes far larger than the variation of cross
N-values and soil density, strength or stiffness. Alternatively,
section changes found among common drill rod types (for example, AW,
the N-value can be used directly in foundation design using
BW, NWor N3), and (d) many drillers have and therefore mix both heavy
correlations to design parameters such as allowable bearing
and light section rods, particularly of the NW type), making it practically
pressure or pile capacity. The N-value depends on the soil
impossible to measure with identical cross sections.
properties but also on the mass, geometry, stroke, anvil, and
5.2 Apparatus to Measure Force—Force data shall be ob-
operating efficiency of the hammer. This energy measurement
tained by attaching foil strain gauges in a full bridge circuit to
procedure can evaluate variations of N-value resulting from
the instrumented subassembly. The gauges shall be arranged
differences in the hammer system. See also Refs (1-6).
symmetrically such that all bending effects are canceled. The
4.2 There is an approximate, linear relationship between the
instrumented subassembly shall have a minimum of two such
incremental penetration of a penetrometer and the energy from
full bridge circuits. Transducer systems that insert elements or
the hammer that enters the drill rods, and therefore an
load cells with stiffness properties substantially different than
approximate inverse relationship between the N-value and the
those of the rods themselves are specifically prohibited.
energy delivered to the drill rods.
5.3 Apparatus to Measure Acceleration—Acceleration data
NOTE 1—Since the measured energy includes the extra potential energy
shall be obtained with a minimum of two accelerometers
effect due to the set per blow, tests for energy evaluation of the hammer
systems should be limited to moderate N-value ranges between 10 and 50 attached on diametrically opposite sides of the instrumented
(Ref (7)).
subassembly within 100 mm (4 in.) of the force measurement
location. The accelerometers shall be aligned axially with the
rod in their sensing direction and shall be bolted, glued, or
welded to the rod with small rigid (solid, nearly cubic shape)
The boldface numbers in parentheses refer to the list of references at the end of
this standard. metal mounts. Overhanging brackets that can bend during
D4633 − 16
impact and plastic mounting blocks are prohibited.Accelerom- within 62 %.Theinstrumentedsubassemblyshallbeloadedto
eters shall be linear to at least 10 000 g and have a useable at least 70 % of the anticipated force. The strain calibration
frequency response to at least 4.5 kHz. allows direct comparison of strain with particle velocity. The
NOTE 4—The rigidity of the accelerometer mounting block can be
dual calibration allows determination of the calculated effec-
assessed by comparing the rise times of the velocity to the force signal.
tiverodcross-sectionalarea, A ,oftheinstrumentedsubassem-
c
5.4 Apparatus for Recording, Processing and Displaying bly from A =(F/Eε) where F is the applied measured force, E
c
Data: is the modulus of steel of 206 000 MPa (29 900 ksi), and ε is
5.4.1 General—The force and acceleration signals from the the measured strain at applied force F. If the calculated and
hammer impact shall be transmitted to an instrument for measured rod areas at the transducer section differ by more
recording, processing, and displaying data to allow determina- than 5 percent, then the rod should be re-calibrated, or the area
tion of the force and velocity versus time. The apparatus shall re-measured. If differences persist, the calculated area is
provide power and signal conditioning for all transducers.
considered more accurate.
There are two forms of data acquisition systems. Analog
6.2 Accelerometer Calibration—The accelerometer shall be
systems electronically integrate measured acceleration to ve-
calibrated to an accuracy within 63 % with a shock of at least
locity through electronic circuitry and digitize the resulting
2000 g’s using a Hopkinson’s Bar with a steel to steel impact.
velocity.Digitalsystemsacquireaccelerationdataanddigitally
The accelerometers shall be attached to the instrumented
integrate acceleration to velocity.
Hopkinson’s Bar measuring strain, and the measured velocity
5.4.2 Analog Systems—Thesignalconditioningsystemshall
from integration of acceleration compared with the measured
apply a low-pass filter to both force and velocity with a cutoff
strain which is theoretically proportional to velocity to check
frequency of 2 kHz or higher (preferably 5 kHz). Data
the acceleration calibration factor. The Hopkinson’s Bar shall
acquisition sampling rate shall be at least five times the
be steel and be at least 10 m (33 ft) long with no welds or
low-pass filter frequency to avoid signal aliasing. Automatic
joints. The impacting bar shall also be steel, of the same area
balancing must be turned off during the impact event.
as the Hopkinson’s Bar, and between 3 and 6 m (10 and 20 ft)
5.4.3 Digital Systems—The signal conditioning shall apply
long.
a low-pass filter to both force and acceleration with a cutoff
6.3 Frequency of Calibration—Force calibration and accel-
frequency of 5 kHz or higher (preferably 25 kHz) (Ref (8)).To
erationcalibrationshallbeperformedatregulartimeperiodsor
avoid aliasing, data acquisition sampling rate shall be at least
atfrequencyofuseasrequiredinthequalityassuranceplanfor
ten times the low-pass filter frequency for single sampling of
the company, project, or as recommended by the manufacturer,
each data point, or at least five times the low-pass filter
or every three years whichever is least. If maintenance is
frequency for analog to digital convertors with oversampling if
performed on the instrumented subassembly (for example,
the oversampling rate is at least 256 times the retained
repair), the unit shall be recalibrated before it is used again.
sampling rate.
5.4.4 Apparatus for Recording—The apparatus shall sample
7. Procedure
each signal and record the magnitude versus time of each
7.1 Observe the penetrometer testing in progress for a
sensor in digital form with a minimum 12-bit resolution. The
preparatory sequences of blows prior to energy measurement.
signals from individual transducers for each blow shall be
Determine and record information, including drill rig type and
permanently stored in digital form for a minimum time sample
serial number; hammer type and serial number; when
so that the motion has ceased, or 50 milliseconds, whichever is
applicable, a description of the cathead system (for example,
longer. The zero line of the acceleration shall be determined
number of rope turns, drop height, rope over or under the
such that the velocity near the end of the sample shall be zero.
cathead, rope condition, crown sheave arrangement); for safety
5.4.5 Apparatus for Processing—The apparatus for process-
hammers, note guide rod size and if hollow or solid; when
ing the data shall be a digital computer or microprocessor
applicable, a description of automatic-trip system, drop height,
capable of analyzing all data and computing results. The
and blow rate. Note any significant hammer operating condi-
measured acceleration shall be integrated to obtain velocity.
tions such as weather, verticality, or changes in lubrication.
Small time shifts between the force and velocity should be
Record drill rod dimensions, including outside and inside
eliminated by time shifting one signal versus the other to
diameters, section lengths, and type of connectors.
account for small phase shifts up to at most 0.1 milliseconds.
Larger time shifts indicate deficiencies in the measurement
NOTE 5—Ideally, do not combine drill rods of varying sizes (for
example, AW with NW) in the drill string below the instrumented
system and should be corrected.
subassembly. Energy is calculated as per 8.1 using the properties of the
5.4.6 Apparatus for Data Display—The apparatus shall
instrumented subassembly.
display the force and velocity signals graphically as a function
NOTE 6—The number, size, and condition of pulley sheaves affects the
of time. The apparatus shall be capable of reviewing each
energy transfer. Energy is consumed in the friction and rotation of the
individual measured signal to confirm data quality during
sheave and thus they should be inspected and their number and condition
noted. Verticality may affect the drop system; align the penetrometer
acquisition as described in 7.8. The apparatus for display shall
system as close to vertical as possible. Because some automatic hammers
display the 2L/c time and the calculated energy result (see 8.1).
are rate dependent, determine the hammer manufacturer’s proper operat-
ingrate.Iftherateisdifferent,recommendhammermaintenance.Weather
6. Calibration
conditions can affect rope and cathead operations.
6.1 Force Calibration—The instrumented subassembly
NOTE7—Preparatorysequencesofblowshavetheobjectiveofbringing
shall be calibrated both in force and strain, each to an accuracy the equipment and operator to their normal functioning condition. The
D4633 − 16
initial blows can be used to re-polish the cathead, dry a wet or damp rope,
7.10 Rig Calibration Interval—Calibrate each hammer at
provide fresh lubrication for mechanical parts, identify any mechanical or
least yearly, or based on frequency of use as specified in the
human problems, and provide re-familiarization practice for all personnel.
owner’s quality assurance plan, or based on the client’s quality
7.2 Enter the test information including the project name,
assurance requirements, whichever is less.
the boring name and location, operating crew names, reference
NOTE 9—For frequently used hammers subject to wear, the required
elevations, the depth of the penetrometer, and any other
interval might be shorter. For infrequently used hammer systems, it is
descriptive information deemed useful. Record any unusual
advisabletocalibrateonfirstuse.Ropeandcatheadoperatedhammersare
conditions or requirements that may affect the test results.
operatordependentandmayrequiremorefrequentcalibrationasoperators
change. It is desirable to calibrate prior to starting major critical projects.
7.3 Enter the information describing the instrumented sub-
7.11 To ensure that the electronics are properly calibrated,
assembly and drill rod including the instrumented subassembly
the energy measurement system shall be checked with a
type (for example, AW, NW-heavy, etc.), cross-sectional area,
built-in or external signal generator with known calibrated
the length from the hammer impact surface to the transducers,
signals.The resu
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D4633 − 10 D4633 − 16
Standard Test Method for
Energy Measurement for Dynamic Penetrometers
This standard is issued under the fixed designation D4633; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Scope*
1.1 This test method describes procedures for measuring the energy that enters the penetrometer drill rod string during dynamic
penetrometer testing of soil due to the hammer impact.
1.2 This test has particular application to the comparative evaluation of N-values obtained from the Standard Penetration Tests
(SPT) of soils in an open hole as in Test Method D1586 and Practice D6066. This procedure may also be applicable to other
dynamic penetrometer tests.
1.3 The values stated in SI units are to be regarded as standard. The inch-pound units given in parentheses are mathematical
conversions which are provided for information purposes only and are not considered standard. Reporting of test results in units
other than SI shall not be regarded as nonconformance with this test method.
1.3.1 The converted inch-pound units use the gravitational system of units. In this system, the pound (lbf) represents a unit of
force (weight), while the unit for mass is slugs. The converted slug unit is not given, unless dynamic (F = ma) calculations are
involved.
1.4 Limitations—This test method applies to penetrometers driven from above the ground surface. It is not intended for use with
down-hole hammers.
1.5 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice
D6026.
1.5.1 The procedures used to specify how data are collected/recorded or calculated, in this standard are regarded as the industry
standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not
consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s objectives;
and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations.
It is beyond the scope of this standard to consider significant digits used in analytical methods for engineering design.
1.6 The method used to specify how data are collected, calculated, or recorded in this standard is not directly related to how
the data can be applied in design or other uses, since that is beyond its scope. Practicetext of this standard references notes and
footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be
considered as requirements of the D6066 specifies how these data may be normalized.standard.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D653 Terminology Relating to Soil, Rock, and Contained Fluids
D1586 Test Method for Penetration Test (SPT) and Split-Barrel Sampling of Soils
D3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in
Engineering Design and Construction
D6026 Practice for Using Significant Digits in Geotechnical Data
This test method is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.02 on Sampling and Related
Field Testing for Soil Evaluations.
Current edition approved Jan. 1, 2010July 1, 2016. Published February 2010July 2016. Originally approved in 2005. Last previous edition approved in 20052010 as
D4633 – 05.D4633 – 10. DOI: 10.1520/D4633-10.10.1520/D4633-16.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4633 − 16
D6066 Practice for Determining the Normalized Penetration Resistance of Sands for Evaluation of Liquefaction Potential
3. Terminology
3.1 Definitions:
3.1.1 For definitions of common technical terms used in this standard, refer to Terminology D653.
3.2 Definitions of Terms Specific to This Standard:
3.1.1 acceleration transducer, or accelerometer—instrument attached on, around, or within a continuous column of drill rods
to measure the time-varying acceleration generated in the drill rods by the impact of the hammer.
3.2.1 anvil—anvil, n—the mass at the top of the drill rods that is struck by the hammer.
3.2.2 drill rods—rods, n—the steel rods connecting the hammer system above the ground surface to the sampler below the
surface.
3.1.4 force transducer—a section of drill rod instrumented with strain gages and inserted into the continuous column of drill
rods to measure the time-varying force generated in the drill rods by the impact of the hammer.
3.2.3 hammer—hammer, n—an impact mass that is raised and dropped to create an impact on the drill rods.
3.2.4 impedance (of the drill rod)—rod), n—a property of the drill rod equal to the drill rod elastic modulus times the cross
sectional area divided by the velocity of wave propagation.
3.2.5 instrumented subassembly—subassembly, n—a short section of drill rod instrumented to measure force and acceleration
which is inserted at the top of the drill rod and below the anvil.
3.2.6 penetrometer—penetrometer, n—any sampler, cone, blade, or other instrument placed at the bottom of the drill rods.
3.2 Symbols:
EFV = the energy transmitted to the drill rod from the hammer during the impact event (see 7.10).
ETR = (EFV / PE) – ratio of the measured energy transferred to the drill rods to the theoretical potential energy.
L = length between the location of transducers on the instrumented subassembly and the bottom of the penetrometer.
2L/c = the time required for the stress wave (traveling at a known wave speed, c, in steel of 5123 m/s (16 810 ft/s)) to travel
from the measurement location to the bottom of the penetrometer and return to the measurement location.
N-value = the number of hammer blows required to advance the 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 hammer positioned at the specified height above the impact surface.
3.3 Symbols:
3.3.1 EFV—the energy transmitted to the drill rod from the hammer during the impact event (see 8.1).
3.3.2 ETR—(EFV / PE) – ratio of the measured energy transferred to the drill rods to the theoretical potential energy.
3.3.3 L—length between the location of transducers on the instrumented subassembly and the bottom of the penetrometer.
3.3.4 2L/c—the time required for the stress wave (traveling at a known wave speed, c, in steel of 5123 m/s (16 810 ft/s)) to travel
from the measurement location to the bottom of the penetrometer and return to the measurement location.
3.3.5 N —standard penetration resistance adjusted to a 60 % drill rod energy transfer ratio.
3.3.6 N-value—the number of hammer blows required to advance the sampler the last 0.305 m (1.00 ft) of the 0.457 m (1.5 ft)
driven during an SPT test.
3.3.7 PE—the theoretical potential energy of the hammer positioned at the specified height above the impact surface.
4. Significance and Use
4.1 Various driven in situ penetrometers are used to evaluate the engineering behavior of soils. The Standard Penetration Test
is the most common type. Engineering properties can be estimated on the basis of empirical correlations between N-values and
soil density, strength or stiffness. Alternatively, the N-value can be used directly in foundation design using correlations to design
parameters such as allowable bearing pressure or pile capacity. The N-value depends on the soil properties but also on the mass,
geometry, stroke, anvil, and operating efficiency of the hammer. This energy measurement procedure can evaluate variations of
N-value resulting from differences in the hammer system. See also Refs (1-6).
4.2 There is an approximate, linear relationship between the incremental penetration of a penetrometer and the energy from the
hammer that enters the drill rods, and therefore an approximate inverse relationship between the N-value and the energy delivered
to the drill rods.
NOTE 1—Since the measured energy includes the extra potential energy effect due to the set per blow, tests for energy evaluation of the hammer systems
should be limited to moderate N-value ranges between 10 and 50 (Ref (7)).
The boldface numbers in parentheses refer to the list of references at the end of this standard.
D4633 − 16
4.3 Stress wave energy measurements on penetrometers may evaluate both operator-dependent cathead and rope hammer
systems and relatively operator-independent automatic systems.
4.4 The energy measurement has direct application for liquefaction evaluation for sands as referenced in Practice D6066.
4.5 This test method is useful for comparing the N-values produced by different equipment or operators performing SPT testing
at the same site, aiding the design of penetrometer systems, training of dynamic penetrometer system operators, and developing
conversion factors between different types of dynamic penetration tests.
NOTE 2—The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the
equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing and
inspection. testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable
results. Reliable results depend on many factors: Practice D3740 provides a means of evaluating some of those factors.
5. Apparatus
5.1 Apparatus for Measurement—An instrumented subassembly defined in 3.1.73.2.5 shall be inserted at the top of the drill rod
string directly below the hammer and anvil system so that the hammer impact is transmitted through the anvil into the instrumented
subassembly and then into the drill rods. The subassembly shall be made of steel drill rod and shall be at least 0.60 m (2 ft) in
length. The measurement location of force and accelerationthe strain gauges and accelerometers shall be located at least 0.30 m
(1 ft) below the top of the instrumented subassembly, and shall be at least three diameters away from any cross sectional area
change.
NOTE 3—While having the same nominal area for the instrumented subsectionsubassembly as the drill string is desirable, variations in area are
unavoidable since (a) the drill rods wear, (b) drill rod manufacture tolerance of wall thickness is rather loose, (c) joints already impose significant cross
section changes far larger than the variation of cross section changes found among common drill rod types (for example, AW, BW, NW or N3), and (d)
many drillers have and therefore mix both heavy and light section rods, particularly of the NW type), making it practically impossible to measure with
identical cross sections.
5.2 Apparatus to Measure Force—The force in the drill rods Force data shall be measured by instrumenting the subassembly
with obtained by attaching foil strain gagesgauges in a full bridge circuit. The gagescircuit to the instrumented subassembly. The
gauges shall be arranged symmetrically such that all bending effects are canceled. The instrumented rod section subassembly shall
have a minimum of two such full bridge circuits. Transducer systems that insert massive elements or load cells with stiffness
properties substantially different than those of the rods themselves are specifically prohibited.
5.3 Apparatus to Measure Acceleration—Acceleration data shall be obtained with a minimum of two accelerometers attached
on diametrically opposite sides of the drill rodinstrumented subassembly within 100 mm (4 in.) of the force measurement location.
The accelerometers shall be aligned axially with the rod in their sensitivesensing direction and shall be bolted, glued, or welded
to the rod with small rigid (solid, nearly cubic shape) metal mounts. Overhanging brackets that can bend during impact and plastic
mounting blocks are prohibited. Accelerometers shall be linear to at least 10 000 g and have a useable frequency response to at
least 4.5 kHz.
NOTE 4—The rigidity of the accelerometer mounting block can be assessed by comparing the rise times of the velocity to the force signal.
5.4 Apparatus for Recording, Processing and Displaying Data:
5.4.1 General—The force and acceleration signals from the hammer impact shall be transmitted to an instrument for recording,
processing, and displaying data to allow determination of the force and velocity versus time. The apparatus shall provide power
and signal conditioning for all transducers. There are two forms of data acquisition systems. Analog systems electronically
integrate measured acceleration to velocity through electronic circuitry and digitize the resulting velocity. Digital systems acquire
acceleration data and digitally integrate acceleration to velocity.
5.4.2 Analog Systems—The signal conditioning system shall apply a low-pass filter to both force and velocity with a cutoff
frequency of 2 kHz or higher (preferably 5 kHz). Data acquisition sampling rate shall be at least 5five times the low-pass filter
frequency to avoid signal aliasing. Automatic balancing must be turned off during the impact event.
5.4.3 Digital Systems—The signal conditioning shall apply a low-pass filter to both force and acceleration with a cutoff
frequency of 5 kHz or higher (preferably 25 kHz) (Ref (8)). To avoid aliasing, data acquisition sampling rate shall be at least 10ten
times the low-pass filter frequency for single sampling of each data point, or at least 5five times the low-pass filter frequency for
analog to digital convertors with oversampling if the oversampling rate is at least 256 times the retained sampling rate.
5.4.4 Apparatus for Recording—The apparatus shall sample each signal and record the magnitude versus time of each sensor
in digital form with a minimum 12-bit resolution. The signals from individual transducers for each blow shall be permanently
stored in digital form for a minimum time sample so that the motion has ceased, or 50 milliseconds, whichever is longer. The zero
line of the acceleration shall be determined such that the velocity near the end of the sample shall be zero.
5.4.5 Apparatus for Processing—The apparatus for processing the data shall be a digital computer or microprocessor capable
of analyzing all data and computing results. The measured acceleration shall be integrated to obtain velocity. Small time shifts
between the force and velocity should be eliminated by time shifting one signal versus the other to account for small phase shifts
up to at most 0.1 milliseconds. Larger time shifts indicate deficiencies in the measurement system and should be corrected.
D4633 − 16
5.4.6 Apparatus for Data Display—The apparatus shall display the force and velocity signals graphically as a function of time.
The apparatus shall be capable of reviewing each individual measured signal to confirm data quality during acquisition as described
in 7.8. The apparatus for display shall display the 2L/c time and the calculated energy result (see 7.108.1).
6. Calibration
6.1 Force Transducer—Calibration—The instrumented subassembly shall be calibrated both in force and strain, each to an
accuracy within 62 %,62 %. The instrumented subassembly shall be loaded to at least 70 % of the anticipated force. The strain
calibration allows direct comparison of strain with particle velocity. The dual calibration allows determination of the calculated
effective rod cross-sectional area, A , of the instrumented subassembly from A = (F/Eε) where F is the applied measured force,
c c
E is the modulus of steel of 206 000 MPa (29 900 ksi), and ε is the measured strain at applied force F. If the calculated and
measured rod areas at the transducer section differ by more than 5 percent, then the rod should be re-calibrated, or the area
re-measured. If differences persist, the calculated area is considered more accurate.
6.2 Accelerometer Calibration—The accelerometer shall be calibrated to an accuracy within 63 % with a shock of at least 2000
g’s using a Hopkinson’s Bar with a steel to steel impact. The accelerometers shall be attached to the instrumented Hopkinson’s
Bar measuring strain, and the measured velocity from integration of acceleration compared with the measured strain which is
theoretically proportional to velocity to check the acceleration calibration factor. The Hopkinson’s Bar shall be steel and be at least
10 m (33 ft) long with no welds or joints. The impacting bar shall also be steel, of the same area as the Hopkinson’s Bar, and
between 3 and 6 m (10 and 20 ft) long.
6.3 Frequency of Calibration—Calibrate forceForce calibration and acceleration transducers calibration shall be performed at
regular time periods or at frequency of use as required in the quality assurance plan for the company, project, or as recommended
by the manufacturer, or every three years whichever is least. If maintenance is performed on the instrumented subassembly (for
example, repair), the unit shall be recalibrated before it is used again.
7. Procedure
7.1 Observe the penetrometer testing in progress for a preparatory sequences of blows prior to energy measurement. Determine
and record information, including drill rig type and serial number; hammer type and serial number; when applicable, a description
of the cathead system (for example, number of rope turns, drop height, rope over or under the cathead, rope condition, crown
sheave arrangement); for safety hammers, note guide rod size and if hollow or solid; when applicable, a description of
automatic-trip system, drop height, and blow rate. Note any significant hammer operating conditions such as weather, verticality,
or changes in lubrication. Record drill rod dimensions, including outside and inside diameters, section lengths, and type of
connectors.
NOTE 5—Ideally, do not combine drill rods of varying sizes (for example, AW with NW) in the drill string below the instrumented subassembly. Energy
is calculated as per 7.108.1 using the properties of the instrumented subassembly.
NOTE 6—The number, size, and condition of pulley sheaves affects the energy transfer. Energy is consumed in the friction and rotation of the sheave
and thus they should be inspected and their number and condition noted. Verticality may affect the drop system; align the penetrometer system as close
to vertical as possible. Because some automatic hammers are rate dependent, determine the hammer manufacturer’s proper operating rate. If the rate is
different, recommend hammer maintenance. Weather conditions can affect rope and cathead operations.
NOTE 7—Preparatory sequences of blows have the objective of bringing the equipment and operator to their normal functioning condition. The initial
blows can be used to re-polish the cathead, dry a wet or damp rope, provide fresh lubrication for mechanical parts, identify any mechanical or human
problems, and provide re-familiarization practice for all personnel.
7.2 Enter the test information including the project name, the boring name and location, operating crew names, reference
elevations, the depth of the penetrometer, and any other descriptive information deemed useful. Record any unusual conditions or
requirements that may affect the test results.
7.3 Enter the information describing the instrumented subassembly and drill rod including the instrumented subassembly type
(for example, AW, NW-heavy, etc.), cross-sectional area, the length from the hammer impact surface to the transducers, and length
from the transducers to the bottom of the drill rod string.
NOTE 8—Energy evaluation of the hammer system is more reliable when the length L is 9 to 12 m (30 to 39 ft) or more.
7.4 Connect the instrumented subassembly for measuring force and acceleration to the top of the drill rod string. The rod joints
should be tight.
7.5 Connect each sensor to the apparatus for recording, processing, and displaying data.
7.6 Follow the manufacturer’s procedures to ensure the transducers and the apparatus for recording, processing, and displaying
data are operating properly.
7.7 Operate the hammer and record the data using the apparatus for recording, processing, and displaying data.
7.8 During testing, the quality of the measurements shall be checked by the operator of the testing equipment.
---------------------- P
...