ASTM D1586/D1586M-18e1

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.
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Designation: D1586/D1586M − 18
Standard Test Method for
Standard Penetration Test (SPT) and Split-Barrel Sampling
of Soils
This standard is issued under the fixed designation D1586/D1586M; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
ε NOTE—Reference (14) was editorially corrected in April 2022.
1. Scope* 1.5 Penetration resistance testing is typically performed at 5
ft [1.5 m] depth intervals or when a significant change of
1.1 This test method describes the procedure, generally
materials is observed during drilling, unless otherwise speci-
known as the Standard Penetration Test (SPT), for driving a
fied.
split-barrel sampler with a 140 lb [63.5 kg] hammer dropped
30 in. [750 mm] to obtain a soil sample for identification
1.6 This test method is limited to use in nonlithified soils
purposes, and measure the resistance of the soil to penetration and soils whose maximum particle size is approximately less
of the standard 2 in. [50 mm] diameter sampler. The SPT “N”
than one-half of the sampler diameter.
value is the number of hammer blows required to drive the
1.7 This test method involves use of rotary drilling equip-
sampler over the depth interval of 0.5 to 1.5 ft [0.15 to 0.45 m]
ment (Guide D5783, Practice D6151/D6151M). Other drilling
of a 1.5 ft [0.45 m] drive interval.
andsamplingprocedures(GuidesD6286andD6169/D6169M)
1.2 Test Method D4633 is generally necessary to measure
are available and may be more appropriate. Considerations for
the drill rod energy of a given drop hammer system and using
hand driving or shallow sampling without boreholes are not
the measured drill rod energy, N values can be corrected to a
addressed. Subsurface investigations should be recorded in
standard energy level. Practice D6066 uses Test Methods
accordance with Practice D5434. Samples should be preserved
D1586 and D4633 and has additional requirements for
and transported in accordance with Practice D4220/D4220M
hammers, hammer energy, and drilling methods to determine
using Group B. Soil samples should be identified by group
energy corrected penetration resistance of loose sands for
name and symbol in accordance with Practice D2488.
liquefaction evaluation.
1.8 All observed and calculated values shall conform to the
1.3 Practice D3550/D3550M is a similar procedure using a
guidelines for significant digits and rounding established in
larger diameter split barrel sampler driven with a hammer
Practice D6026, unless superseded by this test method.
system that may allow for a different hammer mass. The
1.8.1 Theproceduresusedtospecifyhowdataarecollected/
penetrationresistancevaluesfromPracticeD3550/D3550Mdo
recorded and calculated in the standard are regarded as the
not comply with this standard.
industry standard. In addition, they are representative of the
significant digits that generally should be retained. The proce-
1.4 Test results and identification information are used in
dures used do not consider material variation, purpose for
subsurface exploration for a wide range of applications such as
obtaining the data, special purpose studies, or any consider-
geotechnical, geologic, geoenvironmental, or geohydrological
ations for the user’s objectives; and it is common practice to
explorations. When detailed lithology is required for geohy-
increase or reduce significant digits of reported data to be
drological investigations, use of continuous sampling methods
commensuratewiththeseconsiderations.Itisbeyondthescope
(D6282/D6282M, D6151/D6151M, D6914/D6914M) are rec-
of these test methods to consider significant digits used in
ommended when the incremental SPT N value is not needed
analysis methods for engineering data.
for design purposes (see 4.1.1).
1.9 Units—The values stated in either inch-pound or SI
units [presented in brackets] are to be regarded separately as
standard. The values stated in each system may not be exact
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
Rock and is the direct responsibility of Subcommittee D18.02 on Sampling and
equivalents;therefore,eachsystemshallbeusedindependently
Related Field Testing for Soil Evaluations.
of the other. Combining values from the two systems may
Current edition approved Dec. 1, 2018. Published December 2018. Originally
result in non-conformance with the standard. Reporting of test
approved in 1958. Last previous edition approved in 2011 as D1586 – 11. DOI:
10.1520/D1586_D1586M-18E01. results in units other than inch-pound shall not be regarded as
*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
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D1586/D1586M − 18
nonconformance with this practice. SI equivalent units shown D4633 Test Method for Energy Measurement for Dynamic
herein are in general conformance with existing international Penetrometers
standards. D5088 Practice for Decontamination of Field Equipment
Used at Waste Sites
1.10 Penetrationresistancemeasurementsoftenwillinvolve
D5092 Practice for Design and Installation of Groundwater
safety planning, administration, and documentation. This test
Monitoring Wells
method does not purport to address all aspects of exploration
D5299 Guide for Decommissioning of Groundwater Wells,
and site safety.
Vadose Zone Monitoring Devices, Boreholes, and Other
1.11 Performance of the test usually involves use of a drill
Devices for Environmental Activities
rig; therefore, safety requirements as outlined in applicable
D5434 Guide for Field Logging of Subsurface Explorations
safety standards (for example, OSHAregulations, NDADrill-
of Soil and Rock (Withdrawn 2021)
ingSafetyGuide, drillingsafetymanuals,andotherapplicable
D5778 Test Method for Electronic Friction Cone and Piezo-
local agency regulations) must be observed.
cone Penetration Testing of Soils
1.12 This standard does not purport to address all of the
D5782 Guide for Use of Direct Air-Rotary Drilling for
safety concerns, if any, associated with its use. It is the
Geoenvironmental Exploration and the Installation of
responsibility of the user of this standard to establish appro- Subsurface Water-Quality Monitoring Devices
priate safety, health, and environmental practices and deter-
D5783 Guide for Use of Direct Rotary Drilling with Water-
mine the applicability of regulatory limitations prior to use. Based Drilling Fluid for Geoenvironmental Exploration
1.13 This international standard was developed in accor-
and the Installation of Subsurface Water-Quality Monitor-
dance with internationally recognized principles on standard- ing Devices
ization established in the Decision on Principles for the
D5784/D5784M Guide for Use of Hollow-Stem Augers for
Development of International Standards, Guides and Recom- Geoenvironmental Exploration and the Installation of
mendations issued by the World Trade Organization Technical
Subsurface Water Quality Monitoring Devices
Barriers to Trade (TBT) Committee. D5872/D5872M Guide for Use of Casing Advancement
Drilling Methods for Geoenvironmental Exploration and
2. Referenced Documents
Installation of Subsurface Water Quality Monitoring De-
vices
2.1 ASTM Standards:
D6026 Practice for Using Significant Digits and Data Re-
D653 Terminology Relating to Soil, Rock, and Contained
cords in Geotechnical Data
Fluids
D6066 Practice for Determining the Normalized Penetration
D854 Test Methods for Specific Gravity of Soil Solids by
Resistance of Sands for Evaluation of Liquefaction Poten-
Water Pycnometer
tial (Withdrawn 2020)
D1452/D1452M Practice for Soil Exploration and Sampling
D6151/D6151M Practice for Using Hollow-StemAugers for
by Auger Borings
Geotechnical Exploration and Soil Sampling
D1587/D1587M Practice for Thin-Walled Tube Sampling of
D6169/D6169M Guide for Selection of Subsurface Soil and
Fine-Grained Soils for Geotechnical Purposes
Rock Sampling Devices for Environmental and Geotech-
D2216 Test Methods for Laboratory Determination of Water
nical Investigations
(Moisture) Content of Soil and Rock by Mass
D6282/D6282M Guide for Direct Push Soil Sampling for
D2487 Practice for Classification of Soils for Engineering
Environmental Site Characterizations
Purposes (Unified Soil Classification System)
D6286 Guide for Selection of Drilling and Direct Push
D2488 Practice for Description and Identification of Soils
Methods for Geotechnical and Environmental Subsurface
(Visual-Manual Procedures)
Site Characterization
D2573/D2573M Test Method for Field Vane Shear Test in
D6913/D6913M Test Methods for Particle-Size Distribution
Saturated Fine-Grained Soils
(Gradation) of Soils Using Sieve Analysis
D3550/D3550M Practice for Thick Wall, Ring-Lined, Split
D6914/D6914M Practice for Sonic Drilling for Site Charac-
Barrel, Drive Sampling of Soils
terization and the Installation of Subsurface Monitoring
D3740 Practice for Minimum Requirements for Agencies
Devices
Engaged in Testing and/or Inspection of Soil and Rock as
Used in Engineering Design and Construction
3. Terminology
D4220/D4220M Practices for Preserving and Transporting
3.1 Definitions:
Soil Samples
3.1.1 For definitions of common technical terms in this
standard refer to Terminology D653.
3.2 Definitions of Terms Specific to This Standard:
Available from Occupational Safety and Health Administration (OSHA), 200
3.2.1 anvil, n—in drilling, that portion of the drive-weight
Constitution Ave., NW, Washington, DC 20210, http://www.osha.gov.
Available from the National Drilling Association, 3511 Center Rd., Suite 8, assembly which the hammer strikes and through which the
Brunswick, OH 44212, http://www.nda4u.com.
hammer energy passes into the drill rods.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
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D1586/D1586M − 18
3.2.2 cathead, n—in drilling, the rotating drum or windlass driven a prescribed distance of 1.0 ft [0.3 m] after a seating
in the rope-cathead lift system around which the operator interval of 0.5 ft [0.15 m] using a 140 lbm [63.5 kg] hammer
wraps a rope to lift and drop the hammer by successively falling 30 in. [750 mm] for each hammer blow to compute the
tightening and loosening the rope turns around the drum. N-value.
3.2.3 drill rods, n—in drilling, rods used to transmit down- 3.2.10 test interval, n—in drilling, the depth interval for the
ward force and torque to the drill bit while drilling a borehole SPTtest consists of an 0.5 ft [0.15 m] seating interval followed
and also connect sampler to the hammer system for testing. by the 1.0 ft [0.3 m] test interval.
3.2.4 hammer, n—in drilling, that portion of the hammer
3.3 Definitions from D6066 Pertinent to This Standard:
drop system consisting of the 140 6 2 lbm [63.5 6 0.5 kg]
3.3.1 cleanout depth, n—depth that the bottom of the
impact mass which is successively lifted and dropped to
cleanout tool (end of drill bit or cutter teeth) reaches before
provide the impact energy to drill rods that accomplishes the
termination of cleanout procedures.
sampling and penetration.
3.3.2 cleanout interval, n—intervalbetweensuccessivepen-
3.2.5 hammer drop system, n—in drilling, the equipment
etration resistance tests from which material must be removed
that includes the 140 lbm [63.5 kg] hammer, lifting and
using conventional drilling methods.
dropping assembly, and guide tube (if used) which the operator
3.3.2.1 Discussion—During the clean-out process, the pre-
or automatic system accomplishes the lifting and dropping of
vious penetration test interval (1.5 ft [450 mm]) is drilled
the hammer to produce the blow.
throughandanadditionaldistanceiscleanedpasttheenddepth
of the previous test to assure minimal disturbance of the next
3.2.6 hammer fall guide, n—in drilling, that part of the
testinterval.Thetermcleanoutintervalinthispracticerefersto
hammer drop system used to guide the fall of the hammer.
the additional distance past the previous test termination depth.
3.2.7 number of rope turns, n—in drilling, the total contact
3.4 Symbols Specific to This Standard:
angle between the rope and the cathead at the beginning of the
3.4.1 N-value, n—reportedinblowsperfoot,equalsthesum
operator’s rope slackening to drop the hammer, divided by
of the number of blows (N) required to drive the sampler over
360° (see Fig. 1).
the depth interval of 0.5 to 1.5 ft [0.15 to 0.45 m] below the
3.2.8 sampling rods, n—in drilling, rods that connect the
base of the boring (see 8.3).
drive-weight assembly to the sampler. Drill rods are often used
3.4.2 N ,n—standard penetration resistance adjusted to a
for this purpose.
60 % drill rod energy transfer ratio (Test Method D4633,
3.2.9 standard penetration test (SPT), n—in drilling, a test
Practice D6066).
process in the bottom of a borehole in which a split-barrel
sampler (see 5.3) with an outside diameter of 2 in. [50 mm] is 3.5 Symbols Specifc to This Standard and Pertinent to This
Standard from Test Method D4633:
3.5.1 EFV, n—the energy transmitted to the drill rod from
the hammer during the impact event.
3.5.2 ETR, n—ratio (EFV / PE) of the measured energy
transferred to the drill rods to the theoretical potential energy
(PE).
4. Significance and Use
4.1 This test is the most frequently used subsurface explo-
ration drilling test performed worldwide. Numerous interna-
tional and national standards are available for the SPT which
are in general conformance with this standard. The test
provides samples for identification purposes and provides a
measure of penetration resistance which can be used for
geotechnical design purposes. Many local and widely pub-
lished international correlations which relate blow count, or
N-value, to the engineering properties of soils are available for
geotechnical engineering purposes.
4.1.1 Incremental SPT sampling is not a preferred method
of soil sampling for environmental or geohydrological explo-
ration unless the SPT N-value is needed for design purposes.
Continuous sampling methods such as Direct Push Soil Sam-
pling (Guide D6282/D6282M), or continuous coring using
FIG. 1 Definitions of the Number of Rope Turns and the Angle
“Geotechnical Investigation and testing – Field testing- Part 3: Standard
for (a) Counterclockwise Rotation and Penetration Test (ISO 22476-3:2004),” EN ISO 22476-3, European Standard,
(b) Clockwise Rotation of the Cathead European Committee for Standardization, Brussels Belgium.
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D1586/D1586M − 18
Hollow-Stem Augers (Practice D6151/D6151M) or Sonic result in penetration refusal, damage to the equipment, and
Drills (Practice D6914/D6914M) provide the best continuous unreliable N values if gravel plugs the sampler.
record of lithology. Continuous sampling can be performed 4.3.1 Sands—SPTis widely used to determine the engineer-
with SPT samplers, but it is slow compared to other methods, ing properties of drained clean sands during penetration.
and N values may unreliable (see 4.6.1). Sampling for detailed Obtaining “intact” soil samples of clean sands for laboratory
lithology can be reduced by using screening tests such as testing is difficult and expensive (see thin walled tube, Practice
geophysics and Direct Push profiling tests such as Cone D1587/D1587M), so engineers use penetration results in sands
Penetrometers (Test Method D5778), Dynamic Cone for predicting engineering properties (Appendix X1). Appen-
Penetrometer, or electrical resistivity probe. dix X2 and X1.6 provides some estimated properties of sands.
There are problems with SPT in loose sands below the water
4.2 SPT N values are affected by many variables allowed in
table since they are unstable during drilling. Practice D6066
the design and execution of the test (see Appendix X1).
provides restricted drilling methods for SPT in loose sands for
Investigations of energy transmission in SPT testing began in
evaluating earthquake liquefaction potential. Practice D6066
the 1970’s and showed that differing drop hammer systems
method relies on mud rotary drilling, casing advancers, and
provide different energies to the sampler at depth. There are so
fluid filled hollow-stem augers.
manydifferenthammerdesignsthatitisimportanttoobtainthe
4.3.2 Clays—SPT is easy to perform in clays of medium to
energy transfer ratio (ETR) for the hammer system being used
stiff consistency and higher using a variety of drilling methods.
according to Test Method D4633. ETR of various hammer
SPT is unreliable in soft to very soft clays because the clay,
systems has shown to vary between 45 to 95 % of maximum
yields or “fails” under the static weight of the rods alone, or
Potential Energy (PE). Since the N-value is inversely propor-
weight of rods and hammer before the test is started. This
tional to the energy delivered, resulting N values from different
problem is accentuated by the heavier weights of automatic
systems are far from standard. It is now common practice to
hammer assemblies (see X1.3.1.4) but can be alleviated with
correct Nvaluestoanenergylevelof60%oftotal(PE),or N
automatic hammers which are designed to float over the anvil
values as presented here and in Practice D6066. In this
(see 5.4.2.1). There is such a large variation in possible N
standard it is not required to report ETR or N but strongly
values in soft clays it is well accepted that SPT is a poor
advised to be noted and reported if available. If ETR of the
predictor of the undrained shear strength of clay. It is recom-
hammer/anvil/rod system is known, the hammer PE can still
mended to evaluate soft clays with more appropriate methods
vary after calibration, thus it is essential that hammer drop
such as CPT (Test Method D5778), vane shear (Test Method
heights/rates be monitored to confirm consistent performance.
D2573/D2573M), and/or Thin-Wall Tube sampling (Practice
Report any occurrence of hammer drop heights that do not
D1587/D1587M) and laboratory testing.
meet the required value of 30 in. [750 mm] during testing.
Using previous ETR data for a hammer system does not assure 4.4 Hammer Drop System—SPT can be performed with a
that it will perform the same on the current project. If onsite wide variety of hammer drop systems. Typical hammer sys-
ETR is not obtained, be sure to check hammer drop height/ tems are listed below in order of preference of use:
rates to assure the hammer is operating the same as when
(1) Hydraulicautomaticchaincam/mechanicalgrip-release
previously checked. hammers
4.2.1 Othermechanicalvariablesanddrillingerrorscanalso (2) Mechanical trip donut hammers
(3) Rope and cathead operated safety hammers
adversely affect the N value as discussed in X1.4. Drilling
methods can have a major effect on testing (see 4.5).While the (4) Rope and cathead operated donut hammers
SPT hammer system is standardized knowing ETR, drilling 4.4.1 Automatic and trip hammers are preferred for consis-
methods are not, and a variety of drilling methods can be used. tent energy during the test.Automatic chain cam hammers are
also the safest because the hammer is enclosed, and the
4.3 SPT is applicable to a wide range of soils. For nomen-
operators can stand away from the equipment. If the rope and
clature on soil in terms of N-value refer to Appendix X2 for
cathead method is used, the enclosed safety hammer is safer
consistency of clays (cohesive soils) and relative density of
than donut hammer because the impact anvil is enclosed. For
sands (cohesionless soils) as proposed by Terzaghi and Peck
more information on hammer systems, consult X1.3.
and used commonly in geotechnical practice. SPT drilling can
be performed easily using a variety of drilling methods in 4.5 Drilling Methods—The predominant drilling methods
denser soils but has some difficulty in softer and looser soils. used for SPT are open hole fluid rotary drilling (Guide D5783)
Thistestmethodislimitedtonon-lithifiedorun-cementedsoils and hollow-stem auger drilling (Practice D6151/D6151M).
Limited research has been done comparing these methods and
and soils whose maximum particle size is approximately
one-half of the sampler diameter or smaller. Large particles their effects on SPT N values (see X1.5.1.1).
result in higher blow counts and may make the data unsuitable 4.5.1 Research shows that open hole bentonite fluid rotary
for empirical correlations with finer soils. For example, cham- drilling is the most reliable method for most soils below the
ber tests on clean sands have shown coarse sands have higher water table. Hollow-stem augers had problems with saturated
blow counts than medium fine sands (see X1.6). In gravelly loose sands since they must be kept full of fluid. The research
soils, with less than 20 % gravel, liquefaction investigations also showed that driven casing using water as the drilling fluid,
may require recording of penetration per blow in an attempt to can adversely influence the SPT if the casing is driven close to
extrapolate the results to sand blow counts (see X1.7). Soil the test depth interval. Use of casing combined with allowing
deposits containing gravels, cobbles, or boulders typically a fluid imbalance also causes disturbances in sands below the
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D1586/D1586M − 18
watertable.Fluidfilledrotarycasingadvancers(GuideD6286) water content (Test Methods D2216), and specific gravity tests
are included as an allowable drilling method for loose sands in (Test Methods D854). The soil can be reconstituted for some
Practice D6066. advanced laboratory tests. The small-diameter, thick wall,
4.5.2 SPT is used with other drilling methods including drive sampler will not obtain a sample suitable for advanced
reverse circulation, sonic drilling, and direct push methods laboratory tests such as those used for strength or compress-
practices.There are concerns, undocumented by research, with ibility from the core. Consult Guide D6169/D6169M for
direct push (Guide D6282/D6282M), sonic drilling (Practice samplers that provide laboratory grade intact samples.
NOTE 1—The reliability of data and interpretations generated by this
D6914/D6914M), and reverse circulation methods using heavy
practice is dependent on the competence of the personnel performing it
casing drive hammers (Guide D6286), that the extreme dy-
andthesuitabilityoftheequipmentandfacilitiesused.Agenciesthatmeet
namic loading and vibrations could disturb some soils such as
the criteria of Practice D3740 generally are considered capable of
sands and soft clays past the seating interval. The professional
competent testing. Users of this practice are cautioned that compliance
responsible for the investigation should evaluate SPT under with Practice D3740 does not assure reliable testing. Reliable testing
depends on several factors and Practice D3740 provides a means of
these conditions and if drilling disturbance is suspected, then N
evaluating some of these factors.
values can be checked against other drilling methods in section
Practice D3740 was developed for agencies engaged in the testing,
4.5 or deploy the alternate drilling method through and ahead
inspection, or both, of soils and rock. As such, it is not totally applicable
of the casings.
to agencies performing this field test. Users of this test method should
4.5.3 SPT is also performed at shallow depths above the recognize that the framework of Practice D3740 is appropriate for
evaluatingthequalityofanagencyperformingthistestmethod.Currently,
groundwater table using solid stem flight augers (Practice
there is no known qualifying national authority that inspects agencies that
D1452/D1452M), but below the water table borings may be
perform this test method.
subjecttocavingsands.Solidstemboringshavebeendrilledto
depths of 100 ft or more in stable material.
5. Apparatus
4.5.4 SPT is rarely performed in cable tool or air rotary
5.1 Drilling Equipment—Any drilling equipment that pro-
drilling.
vides at the time of sampling a suitable borehole before
4.6 Planning, Execution, and Layout—When SPT borings
insertion of the sampler and ensures that the penetration test is
are used, often there are requirements for other companion
performed on intact soil shall be acceptable. A suitable bore-
borings or test holes to be located near or around the SPT
hole is one in which the drilling indicates stable conditions at
boring. In general, borings should be no closer than 10 ft [3 m]
the base of the boring (see 6.2). In general the boring should
at the surface for depths of up to 100 ft [30 m]. A minimum
haveandiameterof3to6in.[75to150mm]diameter.Borings
would be as close as 5 ft [2 m], but at this spacing, boreholes
greaterthan6in.[150mm]insidediametermayresultinlower
may meet if there is significant vertical deviation.
blow counts and require a correction factor (see X1.5.4).
4.6.1 Test Depth Increments—Test intervals and locations
5.1.1 Fluid Rotary Drilling Drill Bits—Use side discharge
are normally stipulated by the project engineer or geologist.
or baffled bottom discharge bits to avoid jetting fluid distur-
Typical practice is to test at 5 ft [1.5 m] intervals or less in
bance in the base of the boring. The tricone roller bit baffles
homogeneous strata. If a different soil type in the substratum is
produce some downward discharge. If the deposit is fine
encountered, then a test is conducted as soon as the change is
grained, it is preferred to use a fishtail or drag bit with baffled
noted. It is recommended to clean out the borehole a minimum
discharge points to advance the boring. Wash boring chopping
cleanout interval of at least 1 ft [0.25 m] past the termination
bits should not be used near the test zone.
point of the previous test depth between tests to assure test
5.1.2 Hollow-Stem Augers—The boring can be advanced
isolation and to check drill hole condition for the next test.
either using a pilot bit or an interior sampling tube. When
Therefore, the closest spacing for typical practice of SPTis 2.5
drilling below the water table in unstable sands, add water
ft[0.75m].Thecleanoutbetweentestintervalscanbeadjusted
when retrieving the cleanout string and sampler to maintain
by the user depending on borehole conditions and design data
water at or above the groundwater table depth. Two types of
needs such as hard soils or thin strata. The practice of
hollow-stem auger systems are used, either center rod or
performing continuous SPT for N-value determination is not
wireline type. The wireline system suffers from several prob-
recommended but can be done with careful cleanout before
lemswhenunstablesoilsuchassandgetsinsidetheaugersand
testing. The borehole must be cleaned out between tests (see
the pilot bit will not latch. If the bit does not latch, the sand
6.5).At continuous spacing, with no additional cleanout depth,
must be cleared, but often drillers will pull back the outer
N values may be adversely affected by disturbance of previous
augers instead of cleaning causing further disturbance. For that
sample driving especially in softer soils but the effect his not
reason, rod type systems are preferred in unstable soils.
known. Some practitioners like to overdrive the sampler an
5.2 Sampling Rods—Flush-joint steel drill rod shall be used
additional 0.5 ft [0.15 m] to gain additional soil sample for a
to connect the split-barrel sampler to the drive-weight assem-
total drive interval of 2.0 [ 0.6 m]. This is acceptable if the
bly. Drill rod mass per foot ranges from 4 lbm/ft [6 kg/m] to 8
N-value remains the sum of the 0.5 to 1.0 ft [0.15 to 0.3 m]
lbm/ft [12 kg/m]. See X1.4.3 for effects on energy in drill rods.
intervals of the drive interval and reasonable cleanout is
If drill rods are longer than 100 ft [30 m], an energy correction
performed between tests.
may be needed to account for energy loss in long drill strings.
4.7 This test method provides a ClassAand B soil samples
N series drill rods are the maximum size allowed for the test
accordingtoPracticeD4220/D4220Mwhichissuitableforsoil
(see Note 2 and X1.4.3).
identification and classification (Practices D2487 and D2488), NOTE2—InNorthAmerica,drillrodsspecificationscommonlyusedare
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D1586/D1586M − 18
those from the Diamond Drill Core ManufacturersAssociation. The most
% between a constant inside diameter sampler which provides
common drill rods used are A series rods (A, AW, AWJ) of 1.75 in. [45
higher N values than the upset wall sampler and recommends
mm] outside diameter weighing about 4 lbm/ft [6 kg/m]. For depths
that a correction may be required for soils with blow counts
greater than 75 ft [20 m] some publications recommend going to stiffer B
exceeding N>10(seeX1.4.1).Forliquefactionevaluationsitis
orNsizerod.SomeagenciesdrillsolelywithNseriesrodwhichareabout
2.63 in. [67 mm] O.D. and weigh about 8 lb/ft [11 kg/m]. common practice to correct upset wall data to constant diam-
eter using the procedures in X1.4.1.1. Report the type of
5.3 Split-Barrel Sampler—The standard sampler dimen-
sampler used, e.g., Liner or no Liners. Liners are usually steel,
sions are shown in Fig. 2. Samplers are made from steel and in
brass, or plastic and may be sectional and supplied with end
most cases are hardened for durability.The split-barrel sampler
caps for sealing. Report the type of liner used.
must be equipped with a ball check and vent. The sampler has
anoutsidediameterof2.00in.[51mm].Theinsidediameterof 5.3.2 Drive Shoe—Drive shoes are made of steel and should
be hardened for durability. The drive shoe shown on Fig. 2 is
the shoe is 1.375 in. [35 mm]. The inside diameter of the
split-barrel (dimension D in Fig. 2) can be either 1.5 in. [38 the standard for use in finer soils without gravels. Manufactur-
ers do supply thicker more durable shoes for denser soils and
mm] or 1.375 in. [35 mm].The upset portion of the split barrel
may be equipped with liners making the inside diameter 1.375 where coarser soils are encountered (see X1.4.4). The thicker
in. [35 mm]. The length of the sampler should be at least 2 ft shoes are not in conformance with this standard. There is no
[0.6 m] such that it can accommodate the drive interval of 1.5 research on the effect of shoe size/dimensions on N values. If
ft [0.45 m] plus 0.5 ft [0.15 m] of additional length of material.
thicker shoes are used, they should be noted.
This split barrel sampler is also in conformance with Practice
5.3.3 Retainers—Various types of retainers are used for
D3550/D3550M split barrel sampler specifications as shown in
sandy soils which may be difficult to recover. These retainers
Appendix X1, X1.4.2.1, and Fig. X1.6.
cause a restriction to sample entrance and may affect the
5.3.1 Liners—Typical practice in the North America has
N-value. There is no available research on the effect of use of
been to use the upset wall sampler. The use of an upset wall
retainers on blow counts. If retainers are used, they should be
improves recovery of the sample but has been shown to reduce
reported.
friction especially in denser soils. International practice favors
5.3.4 Sampler Maintenance—The sampler must be clean at
the original use of a constant inside diameter sampler. Limited
the beginning of each test and should be smooth and free of
researchsuggeststhat N-valuesmaydifferasmuchas10to30
scars, indentations, and distortions.The driving shoe should be
repaired and restored to specifications tolerances or replaced
when it becomes dented, cracked, or distorted. Plugging of the
DCDMA Technical Manual, National Drilling Association, 6089 Frantz Rd.
vent ports and ball check system of the sampler results in
Suite 101, Dublin, Ohio 43017, 1991.
A = 1.0 to 2.0in. (25to50mm)
B = 18.0 to 30.0 in. (0.457 to 0.762 m)
C = 1.375± 0.005 in. (34.93 ± 0.13 mm)
D = 1.50 ± 0.05 − 0.00 in. (38.1 ± 1.3 − 0.0 mm)
E = 0.10 ± 0.02 in. (2.54 ± 0.25 mm)
F = 2.00 ± 0.05 − 0.00 in. (50.8 ± 1.3 − 0.0 mm)
G = 16.0° to 23.0°
FIG. 2 Split-Barrel Sampler
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D1586/D1586M − 18
unreliable penetration resistance values. Instances of vent port
pluggingmustbenotedondailydatasheetsandreportedinthe
boring log.
5.4 Hammer, Anvil, and Hammer Drop System:
5.4.1 Hammer and Anvil—The hammer shall weigh 140 6
2 lbm [63.5 kg 6 0.5 kg] and shall be a rigid metallic mass.
The hammer shall strike the anvil and make steel on steel
contact when it is dropped. The hammer drop system is to be
designed to permit a constant and unimpeded vertical hammer
fall of 30 in. [750 mm] on the impact anvil which is firmly
connected by threaded connection to the top drill rods. The
anvilactsasanenergydamper,suchthatthetransmittedenergy
through the drill rods is attenuated; therefore, the larger the
anvil the lower the energy transmission. Special precautions
should be taken to ensure that the energy of the falling mass is
not significantly reduced by friction between the drive weight
and guide system. Periodic inspection and maintenance (clean-
ing and lubrication) should be performed to avoid friction
buildup and to check the hammer and assembly mass.
5.4.2 Hammer Drop Systems—Any hammer assembly that
meets the requirements of 5.4.1 may be used for SPT. Various
hammer assemblies as listed here and in section 4.4 may be
used in order of preference.At a minimum, report the type and
details of the hammer system being used. Many hammer
systems have published information on their respective energy
transfer or ETR. However, these should not be relied upon as
manufacturers can change components during their production
life. It is desirable that that actual hammer being used be tested
for ETR within some reasonable time frame. If available,
report the ETR or onsite measured ETR using Test Method
D4633. Report any operational problems when conducting the
test that may impact ETR. If using a previously calibrated
hammer, check and report that the hammer drops heights and
rates still comply with the calibrated condition. The total mass
of the hammer assembly bearing on the drill rods can be
changed to avoid sinking in soft clays (see X1.3.1.4).
5.4.2.1 Automatic Hammer—The typical automatic hammer
finding widespread use in drilling today is an enclosed hydrau-
lic motor operated chain cam hammer lifting system (Fig. 3).
FIG. 3 Typical Hydraulic Automatic Hammer Drop System
These hammers are safer and produce very reproducible drop
heights or energy. These assemblies are often heavy and may
equipped with a view slot on the guide tube to allow drop
add considerable static pressure to the test zone. Some hammer
height checks although some automated systems may not
systems like the Diedrich or eSPT or others are designed to
require it. Heavy automatic hammers resting on the sampler
float over the impact anvil. Many of the automatic drop
may result in unreliable penetration test data in soft and very
hammer systems are built on the drill and may be safely swung
soft clays (see X1.3.1.4). The speed of a chain cam automatic
into position for testing but rest on the impact anvil. The drop
hammer affects the drop height and consequently the energy
height of 30 in. [750 mm] assumes the top of the anvil is fully
transmission, ETR; therefore, the hammers must be routinely
insidetheguidetube.Ifthehammerhasanadjustablefollower,
checked to be sure they are operating at the correct blow rate
the operator should avoid exerting extra pressure on the anvil
and drop height. The automatic hammer system should be
(see X1.3.1.1). A chain cam automatic hammer should be
adjusted to provide the desired blow rate and energy transmis-
sion for the project requirements prior to testing. If ETR data
arenotknown,thenadjustandoperatethehammertoassure30
The Diedrich (www.Diedrichdrill.com), and eSPT (www.marltechnologi-
in. [750 mm] drop height. If ETR is known, an automatic
es.com) hammer systems and laser depth recorder PileTrac (www.piletrac.com) are
hammer may be adjusted to provide drop heights of less than
known to the subcommittee D18.02 at this time with special characteristics cited in
the text. If you are aware of alternative suppliers meeting these criteria or other
30 in. [750 mm] if the blow rate needs to be reduced from
special equipment, please provide this information to the subcommittee D18.02.
manufacturers design speed (see X1.3.1.2).
Other hammer apparatus meeting these features can be added to the standard and
5.4.2.2 Mechanical Trip Donut Hammer Drop System—
will receive careful consideration at a meeting of the responsible technical
committee, which you may attend. These hammer systems use fingers or pawls that grip a donut
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D1586/D1586M − 18
hammer and release the hammer at the 30 in. [750 mm] drop do not significantly affect drop height. These hammers are
height (Fig. 4).The fall guide is a central tube.This hammer is often available internationally even where truck mounted drills
lifted with a rope and cathead but rope turns and cathead speed are not used. They are not as safe as built in automatic
hammers and must be hoisted and lowered using a cathead and
the hammer anvil impact surface is exposed providing a
dangerous pinch point. Some of these hammers have fairly
large anvils which provide lower ETR. Safety problems
include hoisting, lowering, cathead operation pinch points at
the impact surface, and metal fragments which can come off
the anvil.
5.4.2.3 Rope and Cathead Operated Safety Hammer—The
safety hammer drop system shown on Fig. 5 is a long hammer
assembly used on truck mounted drills in North America and
was developed to enclose the impact surface for safer opera-
tion. This hammer system uses an operator cathead rope drop
withtworopeturnsonthecathead.Sinceitisdependentonthe
operator, the energy transmission may vary between operators
and single operator precision has a much larger variation than
automatic hammers. The geometry is slender, with a small
impact anvil, and ETR can be much higher than a donut
hammer (see X1.3.3). In order to allow 30 in. [750 mm] drop
height without back tapping, the hammer lift height should
provide for an additional 3 to 4 in. [75 to 100 mm] of vertical
lift. The hammer should have a mark on the fall guide tube,
which is generally another section ofArod, so the operator can
see the 30 in. [750 mm] drop height. Safety concerns include
hoisting, lowering, and cathead operation.
5.4.2.4 Rope and Cathead Operated Donut Hammer—The
donut hammer is the original design and the dimensions can
vary widely (Fig. 5). Some countries have standardized dimen-
sions of the hammer and anvil to maintain consistent energy
transmission. This hammer system also uses an operator
cathead rope drop with two rope turns on the cathead. Since it
is dependent on the operator, the energy transmission may vary
between operators and single operator precision has a much
larger variation than automatic hammers. Donut hammer with
large impact anvils generally have lower energy transmission
ratios, ETR (see X1.3.4). Safety concerns include hoisting,
lowering,catheadoperation,pinchpointsattheimpactsurface,
and metal fragments off the anvil.
NOTE 3—It is suggested that the hammer fall guide be permanently
marked to enable the operator or inspector to judge the hammer drop
height.
5.4.2.5 Spooling Winch Hammer Systems—This hammer
systemusesanautomatedwirelinespoolbehindthemasttolift
a safety or donut hammer the prescribed 30 in. [750 mm] drop
and then unwind at a computed free fall speed for the hammer
system. Several published studies have shown these hammers
do not perform well and often restrict the drop speed resulting
in very low drill rod energy, ETR and resulting very high blow
counts(seeX1.3.5).Thesehammersystemsshouldnotbeused
unless their performance is checked onsite using energy
measurements prescribed by Test Method D4633.
5.5 Accessory Equipment—Accessories such as labels,
sample containers, data sheets, groundwater level, and SPT
energymeasuringdevicesshallbeprovidedinaccordancewith
the requirements of the project and other applicable ASTM
FIG. 4 Mechanical Automatic Trip Drop Donut Hammer System standards.
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D1586/D1586M − 18
FIG. 5 Schematic Drawing of the Donut Hammer and Safety Hammer (see Note 3)
6. Drilling Procedure 6.2.5 Other Drilling Methods, with concerns listed. It is the
responsibility of the user (driller, site geologist/engineer) to
6.1 The borehole shall be advanced incrementally to permit
examinethetestconditionsandevaluateifdisturbancerequires
intermittent or continuous sampling. Record the depth of
change of drilling method or procedures. Use of fluid rotary or
drilling to the nearest 0.1 ft [0.025 m] or better.
hollow-stem auger drilling is recommended if there are serious
6.2 Any drilling procedure that provides a suitably clean
concerns and a check boring is required. The other drilling
and stable borehole before insertion of the sampler and assures
methods have distinct issues with their usage:
that the penetration test is performed on essentially intact soil
6.2.5.1 Wash Boring Method—Wash borings are an older
shall be acceptable. Stable borehole conditions are confirmed
drilling method using pumped water to a chopping bit which is
for each test by comparing the cleanout depths to sampler
raised and lowered impacting the base of the boring and
depths prior to tests and examining recovered soil cores. Each
circulatingthefluidandcuttingsupward.Casingisalsousedto
of the following procedures has proven to be acceptable for
help keep the boring stabilized. This method has been listed
some subsurface conditions. The subsurface conditions antici-
previously in this procedure but is recognized as a jetting
pated should be considered when selecting the drilling method
method, Section 12 of Guide D6286. Concerns with this
to be used (see 4.5 and 5.1).
method include jetting and impact disturbance in the base of
6.2.1 Open-Hole Fluid Rotary Drilling Method (D5783).
the boring and disturbance caused by casing near the test zone.
6.2.2 Hollow-Stem Auger Method (D6151/D6151M).
See X1.5.1.1 for research information on this method.
6.2.3 Solid Stem Auger Method (D1452/D1452M)—Open
6.2.5.2 Sonic Drilling (D6914/D6914M)—Concerns with
hole solid stem augers can be used to advance borings as long
this drilling method include the strong vibrations produced
as the hole remains open, stable, and clean. These open
which could influence and disturb sandy soils in the test zone.
uncased borings are subject to sloughing or caving of cohe-
This method does not use drilling fluid and disturbance in
sionless soils below the water table and may not be suitable for
those conditions. In stiff cohesive soils borings can often be sands below the water table can occur if fluid balance is not
maintained during removal of the inner barrel. The advantage
extended below the water table. Typical diameter is 4 in. [100
mm]. is the outer casing protect the borehole from caving. There is
some preliminary research on effects of sonic drilling on SPT
6.2.4 Fluid Rotary Casing Advancer (D5872/D5872M)—
Since this drilling method circulates fluids up the exterior N-values which are currently inconclusive (see X1.5.3) point-
ing to a need to perform site specific checks with conventional
annulus of the rotary casing, care must be taken to maintain
fluid circulation (Practice D6066). drilling methods on effect on N-values if required.
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D1586/D1586M − 18
6.2.5.3 Dual-Wall Reverse Circulation—If used with a cas- the hammer drop height (PE) and blow rate should be
ing hammer, this method could disturb sandy soils at the base continuously monitored during testing and any deviations
noted.
of the boring. When drilling with air, circulation must be
maintained as there is high risk of soil fracturing in the test 7.1.1 Automatic and Trip Hammers—By using a trip,
automatic,orsemi-automatichammerdropsystemthatliftsthe
zone. This m
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