ASTM D6169/D6169M-21

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: D6169/D6169M − 21
Standard Guide for
Selection of Subsurface Soil and Rock Sampling Devices
for Environmental and Geotechnical Investigations
This standard is issued under the fixed designation D6169/D6169M; 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* 1.7 This guide offers an organized collection of information
or series of options and does not recommend a specific course
1.1 This guide covers guidance for the selection of soil and
of action. This document cannot replace education and expe-
rocksamplingdevicesusedforthepurposeofcharacterizingin
rience and should be used in conjunction with professional
situphysicalandhydraulicproperties,chemicalcharacteristics,
judgment. The word “Standard” in the title of this document
subsurface lithology, stratigraphy and structure, and hydrogeo-
means that the document has been approved through theASTM
logic units in geotechnical and environmental investigations.
consensus process.
1.2 This guide should be used in conjunction with refer-
1.8 This standard does not purport to address all of the
enced ASTM Guides D420 and D5730, and individual prac-
safety concerns, if any, associated with its use. It is the
tices for sampling devices referenced in 2.1. Soil and rock
responsibility of the user of this standard to establish appro-
samplers are most often used in drilled/pushed boreholes using
priate safety, health, and environmental practices and deter-
various drilling methods/technologies in Guide D6286 and it
mine the applicability of regulatory limitations prior to use.
addresses ability to use these samplers.
1.9 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.3 Refer to Practice D6640 and Guide D4547 for handling
of samples for environmental investigations. Practices D4220/ ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
D4220M and D5079 are used for preserving and transporting
soil and rock samples. mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.4 This guide does not address selection of sampling
devices for hand-held soil sampling equipment (Guide D4700)
2. Referenced Documents
and soil sample collection with solid-stem augering devices
2.1 ASTM Standards:
(Practice D1452/D1452M), or collection of grab samples or
D420 Guide for Site Characterization for Engineering De-
hand-carved block samples (D7015/D7015M) from accessible
sign and Construction Purposes
excavations. Refer to X1.2 for additional guidance on use of
D653 Terminology Relating to Soil, Rock, and Contained
soil and rock sampling devices for both environmental and
Fluids
geotechnical applications.
D1452/D1452M Practice for Soil Exploration and Sampling
1.5 This guide does not address devices for collecting cores
by Auger Borings
from submerged sediments or other sampling devices for solid
D1586/D1586M Test Method for Standard Penetration Test
wastes. Refer to Guides D4823 and D6232 for these materials.
(SPT) and Split-Barrel Sampling of Soils
D1587/D1587M Practice for Thin-Walled Tube Sampling of
1.6 The values stated in either SI units or inch-pound units
Fine-Grained Soils for Geotechnical Purposes
are to be regarded separately as standard. The values stated in
D2113 Practice for Rock Core Drilling and Sampling of
each system may not be exact equivalents; therefore, each
Rock for Site Exploration
system shall be used independently of the other. Combining
D3550/D3550M Practice for Thick Wall, Ring-Lined, Split
values from the two systems may result in non-conformance
Barrel, Drive Sampling of Soils
with the standard.
D3694 Practices for Preparation of Sample Containers and
for Preservation of Organic Constituents
ThisguideisunderthejurisdictionofASTMCommitteeD18onSoilandRock
and is the direct responsibility of Subcommittee D18.21 on Groundwater and
Vadose Zone Investigations For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2021. Published December 2021. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1997. Last previous edition approved in 2013 as D6169 – 13. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D6169_D6169M-21. 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
D6169/D6169M − 21
D3740 Practice for Minimum Requirements for Agencies 3.1.2 intact, adj—in soil and rock, material obtained by a
Engaged in Testing and/or Inspection of Soil and Rock as process following the state of practice (or standard of care)
Used in Engineering Design and Construction intended to preserve in-situ structure, water content, density,
D4220/D4220M Practices for Preserving and Transporting and other properties to a level consistent with the intended
Soil Samples purpose for testing.
D4452 Practice for X-Ray Radiography of Soil Samples
3.2 Definitions of Terms Specific to This Standard:
D4547 Guide for Sampling Waste and Soils for Volatile
3.2.1 borehole grab sampler—a sampling device with a
Organic Compounds
cutting head that advances by rotation and collects a sample by
D4700 Guide for Soil Sampling from the Vadose Zone
scraping side or bottom rather than coring. (See Section 8.1.)
D4823 Guide for Core Sampling Submerged, Unconsoli-
3.2.2 chemically intact core sample—a soil or rock core
dated Sediments
sample in which the sampling device, collection and handling
D5079 Practices for Preserving and Transporting Rock Core
3 procedures result in preservation of the chemical properties to
Samples (Withdrawn 2017)
a degree that satisfies the purpose for which the sample was
D5084 Test Methods for Measurement of Hydraulic Con-
taken.
ductivity of Saturated Porous Materials Using a Flexible
3.2.2.1 Discussion—Fornonsensitivechemicalconstituents,
Wall Permeameter
representative samples (3.2.15) will generally provide chemi-
D5088 Practice for Decontamination of Field Equipment
cally intact samples. Nonrepresentative samples may also be
Used at Waste Sites
chemically intact, but are generally not suitable for analysis
D5608 Practices for Decontamination of Sampling and Non
because of their uncertain integrity, location or origin. For
Sample Contacting Equipment Used at Low Level Radio-
sensitive chemical constituents, special sample collection and
active Waste Sites
handling procedures are generally required to obtain chemi-
D5730 Guide for Site Characterization for Environmental
cally intact samples as discussed in 6.4 and 6.4.3. Physically
Purposes With Emphasis on Soil, Rock, the Vadose Zone
3 intactsamples(3.2.13)willgenerallyprovidechemicallyintact
and Groundwater (Withdrawn 2013)
samples provided that sampling technique, and materials for
D5778 Test Method for Electronic Friction Cone and Piezo-
samplingdevicesandcontainersareselectedtoavoidchemical
cone Penetration Testing of Soils
alteration.
D6001/D6001M Guide for Direct-Push Groundwater Sam-
3.2.3 clearance ratio (inside)—the difference between in-
pling for Environmental Site Characterization
side diameter of the sampling tube and inside diameter of
D6151/D6151M Practice for Using Hollow-StemAugers for
cutting edge or shoe divided by the inside diameter of the
Geotechnical Exploration and Soil Sampling
cutting shoe or edge.
D6232 Guide for Selection of Sampling Equipment for
3.2.3.1 Discussion—Refer to D1587/D1587M, Hvorslev
WasteandContaminatedMediaDataCollectionActivities
(1), and Paikowsky et al. (2) for appropriate formulas for
D6282 Guide for Direct Push Soil Sampling for Environ-
calculating clearance area ratio.
mental Site Characterizations
D6286 Guide for Selection of Drilling and Direct Push
3.2.4 core—for the purposes of this guide, a cylindrical
Methods for Geotechnical and Environmental Subsurface
sample of soil or rock obtained by means of a thick-wall,
Site Characterization
thin-wall, or rotating core sampler.
D6519 Practice for Sampling of Soil Using the Hydrauli-
3.2.5 direct push (DP) method, v—a subsurface investiga-
cally Operated Stationary Piston Sampler
tion method by which drive rod, casing tube, sampling, and
D6640 Practice for Collection and Handling of Soils Ob-
logging devices are pushed, driven, or vibrated into soils or
tained in Core Barrel Samplers for Environmental Inves-
unconsolidated formations to be sampled or logged without
tigations
rotary drilling and removal of cuttings (D6001/D6001M,
D6914/D6914M Practice for Sonic Drilling for Site Charac-
D6286).
terization and the Installation of Subsurface Monitoring
3.2.5.1 Discussion—For the purposes of this guide, a sub-
Devices
surface investigation method that uses hand-held percussion
D7015/D7015M Practices for Obtaining Intact Block (Cubi-
driving devices, or hydraulic percussion, quasi static push, or
cal and Cylindrical) Samples of Soils
vibratory drive systems that are mounted to a truck, van,
D8170 Guide for Using Disposable Handheld Soil Core
all-terrain vehicle, trailer, skid, or drill rig.
Samplers for the Collection and Storage of Soil for
3.2.6 drill rig—for the purposes of this guide, a land-based
Volatile Organic Analysis
wheeled, ATV, or skid-mounted assembly or offshore or barge
mounted assembly capable of drilling boreholes and collecting
3. Terminology
soil or rock samples with a diameter generally greater than 50
3.1 Definitions:
mm [2 in.] using rotary, drive, push, or vibratory advancement
3.1.1 For definitions of general technical terms used within
methods.
this standard, refer to Terminology D653.
3 4
The last approved version of this historical standard is referenced on The boldface numbers given in parentheses refer to a list of references at the
www.astm.org. end of the text.
D6169/D6169M − 21
TABLE 1 General Sample-Type Requirements for Determination
3.2.7 Group A—samples for which only general visual
of Physical and Chemical Properties
identification or profile logging is necessary (see Practice
Physically Chemically
D4220/D4220M).
Tests to be Performed Representative
Intact Intact
3.2.8 Group B—samples for which only water content,
Physical/Hydrologic Properties
classification tests, compaction, and/or bulk samples for labo- Hydraulic Conductivity X . . . . . .
Specific Yield X . . . . . .
ratorypreparedtestspecimensisrequired(seePracticeD4220/
Pressure Head (Matric Potential) X . . . . . .
D4220M). A
Moisture Characteristic Functions X . X
Water Content . . . . . . X
3.2.8.1 Discussion—Group B samples are disturbed, re-
Particle Size Distribution . . . . . . X
molded samples used primarily for engineering properties
Bulk Density/Porosity X . . . . . .
tests. Strength Properties X . . . . . .
Compressibility X . . . . . .
3.2.9 Group C—intact, natural formed or field fabricated,
Mineralogy
Gross Mineralogy . . . . . . X
samples for density determination; or for swell pressure,
Soil Thin Section X . . . . . .
percent swell, consolidation, hydraulic conductivity, and shear
Micromorphology
testing with or without stress-strain and volume change
Surface Properties
Ion Exchange Capacity . . . X . . .
measurements, to include dynamic and cyclic testing (see
Sorption (Batch Tests) . . . X . . .
Practice D4220/D4220M).
Sorption (Flow-Through Tests) X . . . . . .
3.2.9.1 Discussion—Group C samples are physically intact Sorption Site Density . . . X . . .
Surface Area . . . . . . X
samples used primarily for geotechnical engineering properties
B
Non-sensitive Chemical Constituents
tests. Some of these tests, such as bulk density and permeabil-
Most Total Elemental . . . . . . X
ity are useful for environmental investigations. Additional
Concentrations
Carbonate . . . . . . X
physical and hydrologic properties that require Group C type
Soil Organic Carbon . . . . . . X
samples are identified in Table 1.
C
Sensitive Chemical Constituents
Microbiology . . . X . . .
3.2.10 Group D—samplesthatarefragileorhighlysensitive
Volatile and Semi-volatile Organics . . . X . . .
for which tests in Group C are required (see Practices D4220/
Nitrogen- and Sulfur-Containing . . . X . . .
D4220M). Species
Redox-Sensitive Species . . . X . . .
3.2.11 liner—cylindrical tubes or rings made of metal or
(As, Cr, Fe, Mn, Se)
Other Sensitive Inorganics . . . X . . .
plasticplacedinsideacoresamplingdevicetofacilitatesample
(Hg, cyanides)
retrieval and handling.
Per-Polyfluoroalkyl Substances . . . . . . . . .
(PFAS, PFOS,PFOA) X
3.2.12 nonrepresentative sample—a soil sample that con-
A
sists of drill cuttings of uncertain integrity, location or origin, Physically intact sample preferred, but repacked representative sample may be
adequate.
or other incomplete or contaminated portions of subsurface
B
Chemicalconstituentsthataresufficientlystablethatnospecialattentionneedto
materials; generally not suitable for testing or analysis (3).
be given to sample device/container compatibility, or sample handling, transport,
and storage if analyzed within a few months.
3.2.13 physically intact core sample—a soil or rock core
C
Special consideration of sample device/container compatibility, sample
sample in which the sampling device, collection and handling
collection, handling and transport required to obtain chemically intact samples.
procedures result in preservation of the in situ physical and
hydraulic properties (such as, structure, density, and moisture
content) to a degree that satisfies the purpose for which the
in the geologic profession, and differs from the definition of
sample was taken.
representative sample in the statistical sense. The sample is
3.2.13.1 Discussion—Group C and D core samples are
only representative of the subsurface material encountered by
physically intact. Generally, collection of intact samples may
the sampler and is not necessarily representative of the
require use of thin-wall or double-tube rotating core sampling
formation being sampled. Sample representativeness in the
devices, but as discussed in 6.2, thick-wall samplers may be
latter sense needs to be addressed in the sample design that
satisfactory for some objectives.
defines the specific location of sampling.
3.2.14 piston core sampler—a thin-wall or, less commonly,
3.2.16 rotating core sampler—a rotating cylindrical sampler
thick-wall sampling device in which the inner piston is held in
with a coring bit that cuts away soil or rock material from
a fixed position and the cutting head and outer barrel is
around the core. (See 7.6.)
advancedmechanicallyorhydraulicallyintothesoil.(See7.5.)
3.2.17 sensitive chemical constituents—chemical species or
3.2.15 representative soil sample—a soil sample from a
compounds for which the composition or concentration in soil
knownsubsurfaceintervalinwhichsomestructuralfeaturesdo
may change rapidly in soil in response to disturbance, or
notsurvivebutotherproperties,suchasmoisturecontent,grain
interaction with sample container materials, due to processes
size and gradation and chemical characteristics of the sample
such as volatilization, degassing, microbial action or abiotic
interval are preserved; suitable for mechanical and chemical
oxidation-reduction reactions.
analysis for non-sensitive chemical constituents, and lithologic
logging. (See discussion in 6.3.) Adapted from U.S. Geologi- 3.2.18 thick-wall sampler—a core sampler that does not
cal Survey, 1980 (3)
satisfy the requirements for collection of intact Group C and D
3.2.15.1 Discussion—This definition follows general usage samples.
D6169/D6169M − 21
cautioned that compliance with Practice D3740 does not in itself assure
3.2.18.1 Discussion—Generally, samplers with a wall area
reliable results. Reliable results depend on many factors; Practice D3740
ratio greater than 15 percent (see 6.2.2 for additional specifi-
provides a means of evaluating some of those factors.
cations). Typical thick wall samplers are found in Test Method
D1586/D1586M and Practice D3550/D3550M. (See 7.3.) 5. Objectives of Sampling Soil and Rock
3.2.19 thin-wall sampler—a sampler that meets the specifi-
5.1 Samples of soil and rock can be collected for three
cations in Practice D1587/D1587M. (See 7.4.) majorpurposes:testingofengineeringandhydraulicproperties
on intact samples, measurement of in situ chemical and
3.2.20 vibratory core sampling—a sample process in which
biological characteristics, and identification and classification
a thick-wall or thin-wall sampler is advanced using high
of geologic and hydrogeologic characteristics of the subsur-
frequencyvibrationsratherthanhydraulicorpercussionforces.
face. Table 1 identifies general sample-type requirements for
3.2.21 wall area ratio—the ratio of gross wall area due to
measurement of physical, hydrologic and chemical properties
thickness divided by the inside opening of the sampler.
of the subsurface. Most coring devices (see Section 7) provide
3.2.21.1 Discussion—Refer to D1587/D1587M, Hvorslev
goodtoexcellentsamplesforallthreepurposes.Boreholegrab
(1) and Paikowsky et al. (2) for appropriate formulas for
samplers and drill cuttings (see Section 8) are unsuitable for
calculating wall area ratio.
measurement of in situ physical and hydrologic properties and
3.2.22 wireline core sampling—asamplingprocessinwhich
are only useful to get basic information on geologic and
rotating or pushed core samplers are raised and lowered inside
hydrogeologic properties of the subsurface.
drill rods with a wireline and attached for coring or pushing
5.2 Laboratory Testing for Engineering and Hydraulic
with an overshot latching mechanism.
Properties Intact Samples—Laboratory measurements of
physical properties, such as bulk density, porosity, shear
4. Significance and Use
strength, consolidation of clays, hydraulic conductivity, and
4.1 Direct observation of the subsurface by the collection of
thin-section analysis of sediments require intact cores that
soil and rock samples is an essential part of investigation for
retain the in situ properties of the sample. Intact samples
geotechnical and environmental purposes. This guide provides
should best preserve bulk density and porosity, which is
information on the major types of soil and rock sampling
important for both geotechnical and environmental purposes.
devices to assist in selection of devices that are suitable for
Hydraulic properties of permeable materials are generally best
known site geologic conditions, and provide samples that meet
measured using in situ aquifer tests (see Table A1.1 of Guide
projectobjectives.Thisguideshouldnotbeusedasasubstitute
D5730, for list of ASTM standards on aquifer tests), but
for consulting with professional experience in sampling soil or
collection of intact samples for laboratory permeameter tests
rock in similar formations before determining the best method
may provide useful information on vertical changes in hydrau-
and type of sampling.
lic properties depending on the preservation and transport of
the intact sample prior to testing. Impermeable materials, such
4.2 This guide should be used in conjunction with Guide
as clays, are generally best measured in the laboratory using
D6286 on drilling methods and sampling equipment, and
intact cores (see Test Method D5084). However, it should be
diamond drilling Guide D2113. Drilling and sampler specific
recognized that laboratory measurements generally do not
practices and guides listed throughout this guide are used as
consider preferential flow or secondary porosity effects which
part of developing a detailed site investigation and sampling
can significantly affect the field permeability of a material.
plan.Thesamplingplanshouldstartwithdevelopmentofasite
Table 1 lists parameters that require intact samples.
conceptual model and phased investigations to locate sampling
sites (D420, D6286).The selection of sampling equipment and
5.3 Chemical and Biological Characteristics for Ground-
sampling devices goes hand-in-hand. In some cases, soil
water Quality Evaluations—Samples for measurement of
sample requirements may influence choice of drilling method,
stablechemicalconstituentsgenerallydonotrequirephysically
or conversely, types of available sampling equipment may
intact samples, but do require discrete representative samples
influence choice of sampling devices.
that are not subjected to cross contamination. Samples for
measurement of sensitive chemical constituents, such as vola-
4.3 Samples should be handled in accordance with Practice
tile organic compounds require special handling procedures
D4220/D4220M, for preserving and transporting soil samples,
(D6640). Whenever chemical analysis of samples is an objec-
Practice D5079 for preserving and transporting rock core
tive of the investigation, sampling devices that result in
samples for geotechnical purposes. For environmental work
chemical alteration should be avoided. Chemical alteration is
sample handling procedures should be in accordance with
most problematic with devices in which borehole groundwater
Practice D6640 for collection and handling of soils obtained in
or drilling fluids come in direct contact with the sample and
core barrel samplers for environmental investigations, Practice
when sensitive constituents such as volatile organic chemicals
D3694 for preparation of sample containers and for preserva-
and redox sensitive elements (iron, manganese, arsenic,
tion of organic constituents, and Practice D5088 for decon-
chromium,selenium),ormicroorganismsbelowthewatertable
tamination of field equipment used at waste sites.
are to be sampled. In contaminated soil and groundwater,
NOTE 1—The quality of the result produced by this standard is
casing advancement methods such as dual tube direct push or
dependent on the competence of the personnel performing it, and the
sonic drilling should be used to prevent cross-contamination of
suitability of the equipment and facilities used. Agencies that meet the
samples. Sampling for such constituents requires use of sam-
criteria of Practice D3740 are generally considered capable of competent
and objective testing/sampling/inspection/etc. Users of this standard are plers and sampling procedures that avoid or minimize contact
D6169/D6169M − 21
with drilling fluids, the atmosphere, other contaminated soil or insertion. Committee D18 has adopted the term intact sample
groundwater, and sample containers made of nonreactive (3.1.2) to designate that the sample is taken with traditional/
materials(see6.4and6.4.3).Intactsamplesarepreferredwhen
industry standard samplers using a good, accepted practice for
column leaching or sorption tests are to be performed in the standard of care. Intact samplers are usually thin wall tubes or
laboratory, although representative disturbed samples can be
large diameter soil core samplers. Practice D1587/D1587M on
usedinunstructuredsoilmaterialsifthebulkdensityisknown.
the thin wall tube has an extensive discussion of evaluation of
Table 1 identifies types of samples required for specific
the sample quality. By evaluation recompression behavior in
chemical and biological properties.
laboratory consolidation tests of clays, sample quality can be
evaluated, and quality classifications have been proposed
5.4 Geologic Classification, Lithology, and Hydrogeologic
(D1587/D1587M, Appendix). Geotechnical engineers recog-
Properties—Samplesforgeologicproperties,suchaslithology,
nize that in clean, drained, sands it is difficult to obtain a
stratigraphy, and structure should generally be representative.
suitable and Intact sample by insertion of thin wall tube alone,
There are many drilling methods that can continuously sample
which leads to reliance on penetration resistance data such as
formations with disturbed but representative samples and these
D1586/D1586M or other insitu tests such as the cone pen-
are preferred for the best information on the subsurface
etrometer (D5778). In the past, the only intact sampling of
materials. With some drilling methods that do not produce
clean sands was possible by expensive insitu freezing followed
cores, nonrepresentative samples combined with observations
bysoilcoringbuttherearenewpolymergelinjectionsamplers
of drilling advancement rates may provide some information
on changes in lithology if it is not feasible to collect represen- (see 7.5.1 and 7.9.2.1) that are being used. The factors that
affect physical sample disturbance are numerous and complex
tative samples (see 8.3). The quality of definition of geologic
units will be a function of the quality of lithologic, enoughthatprofessionaljudgmentisstillrequiredtodetermine
stratigraphic, and structural interpretations from sampling and whether a sample is physically intact for the intended proposed
supplemented by water level data and aquifer tests. use of the sample.
6.2.2 Effects of Sampling Device on Degree of Physical
6. Specific Criteria for Selection of Sampling Devices
Disturbance—The following three general characteristics of
6.1 When the specific objectives of sample collection have
samplers affect the degree of physical disturbance of the
been defined (see 4.2), the applicable criteria described below
sample: increasing wall thickness increases disturbance, in-
should be identified and the sampling device or devices that
creasing tube diameter decreases disturbance, and increasing
will best fulfill the sampling objectives selected for use. When
tube length increases disturbance.Thin wall push samplers and
a sampling device has been selected, at least two should be
piston samplers with thin-walled tubes are used for intact
procured, along with appropriate spare parts. Two samplers
sampling. Thick wall push or drive samplers cannot provide
may be used in alternation if this enhances efficiency of field
intact samples unless the used specialized thin wall cutting
operations and sample collection, or the second sampler serves
shoe designs (7.4.2.4). Larger Diameter samplers provide
as a backup in the event the first one becomes damaged.
better intact samples as discussed in the thin wall standard
Practice D1587/D1587M where 125 mm [5-in.] samplers are
6.2 Sample Physical Disturbance—The degree of physical
preferred to the smaller minimum diameter of 75 mm [3 in.]
disturbance of a soil or rock sample is primarily a concern
sample tubes. In the thin wall standard 125 mm [5-in.]
when in situ physical and hydraulic properties are to be
samplers can obtain longer samples. The sample diameter rule
measured by laboratory tests. Geotechnical engineers need
applies to other samplers with diameters of 100 to 150 mm [4
intact samples on large projects where the compressibility and
to 6 in.] are preferred. The same sampler may cause different
shearstrengthmustbedeterminedinlaboratorytests.Geotech-
degrees of disturbance, depending on the material being
nical engineers often use thick wall drive samplers for addi-
sampled, with highly plastic and compressible soils and well
tional penetration resistance data and to obtain representative
sorted noncohesive sands being most susceptible to distur-
samples on most all projects. Environmental engineers dealing
bance. Driving the same sampler can disturb a sample more
with subsurface contamination are primarily concerned with
than pushing the sampler. Thin-wall samplers (see 7.4) gener-
hydraulic properties that are best measured by field tests (see
ally provide the highest quality cores in terms of minimizing
5.2). The degree of disturbance also affects the quality of
sample disturbance in fine-grained cohesive materials. Piston
borehole log descriptions and subsequent interpretations de-
samplers (see 7.5) may be required for collecting cores in
rived from laboratory and/or field testing. Disturbed soil cores
cohesionless materials, with thin-wall types creating less dis-
allow logging of primarily textural and density/consistency
turbance than thick-wall types). Rotary core samplers, such as
changes.Intactsoilcoresallowdescriptionofsoilmorphologic
features that are valuable for developing interpretations con- the Denison sampler (see 7.6.2), or vibratory/sonic sampling
methods (see 7.2.4 and 7.3.3) may be required to collect intact
cerning the potential for contaminant movement in the subsur-
face (4). Collection of oriented intact rock cores allow assess- samples in firm to stiff cohesive soils and dense sands. In
extreme cases, such as critical liquefaction studies in clean
ment of fracture location and orientation in the subsurface (see
7.9.4). sands, intact cores can be obtained by freezing or injection of
stabilizers using rotary soil core barrels (7.9.2). Depending on
6.2.1 Discussion of Physically Intact—There is no such
thing as an “undisturbed sample because the sampling process the sampler and soil material, thick-wall samplers may also be
inevitably results in some degree of disturbance as a result of satisfactory for measurement of in situ physical and hydraulic
factors such as stress relief or dilation or compression from properties (see 6.2.3). Shuter and Teasdale (5) and most of the
D6169/D6169M − 21
geotechnical references (6 and 7) identified in the appendix of spatially oriented cores to establish strike and dip of
provide further discussion of considerations and techniques for formation layering and evaluate potential contaminant path-
collecting intact cores.
ways in joint and fracture systems (see 7.9.4).
6.2.3 Criteria for Evaluating Degree of Physical Distur-
6.3 Sample Representativeness—Group B soil samples as
bance in Push and Drive Samples—Table 2 identifies the main
defined in Practice D4220/D4220M are physically representa-
sampler characteristics that determine whether a sample is
tiveofthesampledintervalandareprimarilyusedforsoil/rock
physically intact for Group C and D samples as defined in
classification and subsurface logging for lithology evaluation.
Practice D4220/D4220M. Although the definition of these
Soil samples from a known subsurface interval that do not
groups has a primarily geotechnical focus, intact samples for
preserve in situ structural properties, but for which other
hydrogeologic analysis and testing have the same requirements
physical properties such as water content and particle size
(Refer to Shuter and Teasdale (5) for a detailed discussion of
distribution or chemistry, or combination thereof, are
requirements for intact soil samples for hydrogeologic analysis
unaltered, are representative samples. Geotechnical engineers
and testing). Groups C and D samples will also provide high
often use incremental thick wall drive samplers (D1586/
quality samples for visual logging of soil morphologic and
sedimentary features that are sensitive to disturbance by D1586M, D3550/D3550M) with added benefit of using pen-
thick-wall samplers. Table 3 gives a number of indicators that etration resistance data to estimate engineering properties. In
can be used to evaluate the degree of disturbance in core environmental work, continuous representative sampling using
collected using a thick-wall sampler. X-ray radiography (see
direct push methods (7.3.2), sonic core (7.3.3), or hollow-stem
Practice D4452) may also be useful for evaluating the quality
augers (7.6.3) are used since drilling/sampling methods are
of Group C and D cores.
preferred since no fluids are used in the drilling process. When
6.2.4 When to Collect Physically Intact Soil Samples—
drilling methods involve drilling fluids, sample moisture con-
Environmental Investigations—Intact physical soil samples in
tentandchemistrymaybealtered.Drillcuttingsorauger-flight
cohesionless soils (sands and gravels) are generally more
samples are inadequate for most investigations (8.3). Borehole
costly in time and money than disturbed samples, and in
grab samples and drill cuttings may be representative if the
environmental investigations the decision to obtain intact
sample collection method allows precise determination of the
samples should be based on a judgment that the added
sample interval, measures are taken to prevent mixing of
information obtained from intact cores outweighs the added
material from other intervals, and the drilling method does not
costs. Examples of when high-quality intact samples (Groups
alter sample characteristics (see 8.4).
C and D) in environmental investigations might be appropriate
6.4 Sample Chemical Integrity—Soil samples collected for
for environmental investigations include: determination of
chemical analysis usually do not need to preserve in situ
laboratory hydraulic conductivity and porosity for calibration
structural characteristics of the sample but must be represen-
of geophysical logs in an area, thin section examination of
tative of the sampled interval. Relatively stable chemical
sediments for mineralogy and microstructural features, engi-
properties, such as mineralogy, organic matter content (exclud-
neering properties for fill/cut slope stability, slurry walls and
backfill design for design of waste disposal facilities and ing recent organic residue) and many inorganic constituents
remediation of contaminated soil and groundwater, collection can be collected using any device that gives a representative
A
TABLE 2 General Sampler Specifications Defining Intact Samples for Group C and D Samples
B C
Sampler Characteristics Intact (Thin-Wall sampler) Disturbed (Thick-Wall sampler) Source
Wall thickness/OD ratio < 2.5 % > 2.5 % Hvorslev (1)
Wall area ratio < 15 % > 15 % Hvorslev (1) and
Paikowsky et al. (2)
Clearance ratio (inside) Shuter and Teasdale (5)
Nonplastic soils 0.5 to 1 % NA and Practice D1587/D1587M.
Intermediate plasticity 1 to 2 % NA See also Table 7.
Plastic soils (clays) 0 to 3 % NA
Length Practice D1587/D1587M
Sands < 10 diameters > 10 diameters
Clays < 15 diameters > 15 diameters
Diameter Shuter and Teasdale (5)
Compressible soils > 75 mm [3 in.] < 75 mm [3 in.]
D D
Less compressible soils > 50 mm [2 in.] < 50 mm [2 in.]
A
Group C samples include samples for the following geotechnical tests: density, percent swell, consolidation, permeability testing and shear testing with or without
stress-strain and volume change measurements. Group D samples are fragile or highly sensitive for which test in Group C are required. Group C samples collected for
environmental testing purposes would include laboratory measurement of hydraulic conductivity, and flow-through core tests for sorption and leachability.
B
Thin-wall samplers cannot get intact samples of all soil materials. For denser soils, Pitcher (see 7.6.1) or Denison samplers (see 7.6.2) may be required.
C
Samples collected with thick-wall samplers may qualify as representative samples for the purpose of description of in situ morphologic properties and for the purpose
of chemical characterization. Thick-walled samplers equipped with thin sharp cutting shoes extensions can be designed to acquire intact samples (6.2).
D
50 mm [2-in.] samples for Group C samples for engineering tests are not recommended.
D6169/D6169M − 21
A
TABLE 3 Indicators of Degree of Core Disturbance in Driven Samples
Indicator Intact/Less Disturbed More Disturbed/Disturbed
Advancement Method Pushed Driven
Core Recovery Core length = sample interval Core length < or > sample interval
A
Soil morphology/sedimentary structures No or little observable deformation Moderate to extensively deformed
B
Core length (indicator of expansion or compaction) Length of core equal to sampled interval Length of core > or < sampled interval
Partings at intervals equal to the distance of each drive Absent Weakly to strongly evident
impact (driven samples only)
Practice D1586/D1586M blow count (N) N <30 N >30
Core shoe (soil with course fragments) No visible damage to cutting shoe Cutting shoe nicked or bent
Gravel fragments or large roots in core No evidence of grooving along core Core has been grooved by rock or root fragments in-
side the core
Borehole condition Cased or stable borehole with no caving Unstable, uncased borehole
Drilling fluid Not used, or not visible Drilling fluid coats core top, bottom and sidewalls
A
Based on visual observation of split cores or X-ray radiography using Test Method D4452.
B
Also indicator for pushed thin-wall samples.
sample. Sensitive chemical constituents, such as redox- Piston samplers results in less cross-contamination than open
sensitive metals, volatile organic chemicals, and other organic thin-wallandthick-wallsamplesbothaboveandbelowawater
chemicals that are subject to biodegradation may require table. Piston samplers used below the water table in contami-
collection of intact or relatively intact samples using stainless
nated aquifers should have good seals (O-rings or leather
steel or brass liners or clear plastic (typically PVC) liners that packing) to prevent water from entering the sampler before it
are immediately sealed for transport or special coring, paring,
is in position. A common problem with soil sampling is
or sub-coring devices that allow rapid placement or transfer of
groundwater cross contamination below the water table. Most
samples into containers for onsite analysis or preservation and
drilling and direct push methods using open boreholes and
transport to a laboratory.
casingwillhavestandinggroundwaterbelowthewatertablein
6.4.1 Sampling equipment must be cleaned a decontami-
the borehole that has the potential to cross contaminate
nated prior to and in between sampling events. Consult
subsequent deeper sampling. In cases where there is standing
practices D5088 and D5608 for methods to decontaminate
water in the borehole, the sampling procedure should be
sampling equipment and perform in accordance with the site
changedtousingsealedsamplerlikethesingletubedirectpush
sampling plan. New samplers should be cleaned prior to use to
sampler (D6282) or a sealed piston sampler if cores are
remove any manufacturing chemicals left on the equipment.
adversely affected.
Sampling equipment may require decontamination when
6.4.4 Lewis et al. (8) and Turriff and Klopp (9) describe
movedbetweensamplingsitesandwhenleavingtheproject.In
special sampling devices, preservation and handling proce-
hole drill rods, augers, and casings should be decontaminated
dures for minimizing loss of volatile constituents from soil
when removed from the sampling site.
samples. Chapelle (10) and Leach et al. (11) describe proce-
6.4.2 Storage of samples in liners are not recommended and
dures and equipment for collecting soil samples that preserve
most soil cores require immediate sub-sampling. Procedures
anaerobic, reducing conditions. Some sampler materials or
for soil core handling for chemical testing are given standard
liner materials may be incompatible or possibly interfere with
D6640. Sampling for Volatile Organic Compounds (VOC) is
analysis of some chemical parameters. For example, stainless
addressed in Guide D4547 and often the core may be rapidly
steel samplers or liners generally should not be used when
sub-sampled on site using other methods such as Guide D8170
chromium is one of the primary analytes of interest. Selecting
or other similar small hand core samplers. Samples for other
the appropriate sample and liner materials before beginning
chemical characterization generally require sub-sampling into
field work.
glass or plastic jars or vials and preserved with refrigeration.
6.5 Nature of Geologic Materials—The type of geologic
Verify containers and preservation requirements meet the data
material to be sampled is a primary consideration in selection
qualityobjectivesasspecifiedbytheleadregulatoryagency,in
of sampling devices, and the ease or difficulty in obtaining an
the project work plan, and with the selected analytical labora-
intact sample. Table 4 provides some general ratings on
tory.
suitability of core sampling devices for different geologic
6.4.3 Prevention of Cross Contamination—Open thin-wall
materials. In geotechnical investigations soils are often classi-
and thick-wall samplers may cause cross-contamination of soil
fied as cohesive (clays) and cohesionless (silt, sand, and
samples by including material from a higher interval. Casing
advancement methods (including continuous sampling with a gravel), with the basic types differentiated based on density or
consistency (12). Table 5 provides criteria used to define
hollow-stem auger, double-tube direct push, or vibratory/sonic
drilling), or stable boreholes where the drilling method has a density/consistency classes based on N values for standard
penetration test (see Practice D1586/D1586M) and unconfined
larger diameter than the sampler help minimize cross-
contamination of sample from above the water table. Tempo- compressive strength. Saturation increases the difficulty in
sampling of all unconsolidated materials, but especially sands.
rary seals for the barrel shoe that are pushed aside when the
sampler enters the soil interval being sampled will prevent Cohesionless well graded sands and sensitive, soft, low plas-
contactoftheinsideofthesamplerwithcontaminatedsoil,soil ticity clays and silts pose the greatest difficulties for collection
gas or groundwater as it advances through an open borehole. of intact samples. Where only representative samples are
D6169/D6169M − 21
A
TABLE 4 Suitability of Core Sampling Devices for Different Geologic Materials
NOTE1—Key:Ratings:E=excellent;G=good;F=fair;P=poor;NA=notapplicable.Other:FD=facedischarge;RBD=recessedbottomdischarge.
B C
Sampler Type Soil/Unconsolidated Material Rock
D
Fine-Grained Coarse, Cohesive Cohesionless
Soft Hard
Soft-Stiff Stiff-Hard Sand Gravel Loose Dense
Drive/Push Samplers
Thick-Wall E-G G-P E-G F-P F-P G-P NA NA
Thin-Wall E F-P G-F NA F-P P NA NA
E
Piston E F-P G-F NA E-P P NA NA
Direct Push F-G G-F F-P NA F-P F-G NA NA
Sonic Core G-P G-E F-E G-E G-F F-E G-E F-G
Rotating Soil Core Samplers
Hollow-Stem Auger G-F E-G E-G F-P F-P G-P NA NA
Pitcher G-F E-G E-G G-P G-P E-P NA NA
F
Denison G-F E-G E-G G-P F-P G-P NA NA
G
Rotating Rock Core Samplers
Single Tube, FD NA NA NA NA NA NA F-P E-P
H
Double Tube RBD P P NA F-P NA G-P E E
Triple Tube P P NA P NA G-P E E
A
Ratings are for general guidance only. Performance of specific sampling devices can vary depending on the type of drill rig, diameter of the sampler and nature of the
geologic material.
B
Refer to Table 5 to density/consistency terminology.
C
Soft rock includes shales, siltstone, and weakly cemented sandstone. Hard rock includes limestone, dolomite, and most igneous and metamorphic rocks.
D
Loose cohesionless soils are difficult to recover with most drive/push sampling devices unless retainers are used, especially when saturated. Materials in this category
include saturated sensitive clays, silts and sands, sensitive organic silts, soft clays, unsaturated loose sands and silty sands. Very dense soil material is also difficult to
penetrate with most drive/push sampling devices. Examples of dense materials would include compact tills and weakly cemented soil/rock.
E
Numerous types of piston samplers have been developed, but only a few are commercially available; many are effective in sampling saturated, cohesive soils, but have
varying effectiveness for sampling cohesionless soils.
F
Denison sampler ratings are for soil sampling configuration with inner barrel advanced ahead of outer rotating core barrel. In the rock coring configuration ratings are
same as for double tube RBD sampler.
G
Numerous types of single- and double-tube rotating core samplers are available, with specific designs and cutting heads selected based on rock hardness and degree
of jointing and fracturing.
H
Only if gravels are very dense or cemented.
A
TABLE 5 Soil Terminology Related to Sample Device Selection
toolsareselected.Proceduresforcollectingcoresamplesusing
Range of Standard Range of Unconfined
some drilling methods such as cable tool and solid stem auger
Density or
Basic Soil Types Penetration Compressive
Consistency are relatively cumbersome compared to sonic, direct push,
B C
Resi
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