ASTM D4700-91(1998)e1
(Guide)Standard Guide for Soil Sampling from the Vadose Zone
Standard Guide for Soil Sampling from the Vadose Zone
SCOPE
1.1 This guide addresses procedures that may be used for obtaining soil samples from the vadose zone (unsaturated zone). Samples can be collected for a variety of reasons including the following:
1.1.1 Stratigraphic description,
1.1.2 Hydraulic conductivity testing,
1.1.3 Moisture content measurement,
1.1.4 Moisture release curve construction,
1.1.5 Geotechnical testing,
1.1.6 Soil gas analyses,
1.1.7 Microorganism extraction, or
1.1.8 Pore liquid and soils chemical analyses.
1.2 This guide focuses on methods that provide soil samples for chemical analyses of the soil or contained liquids or contaminants. However, comments on how methods may be modified for other objectives are included.
1.3 This guide does not describe sampling methods for lithified deposits and rocks (for example, sandstone, shale, tuff, granite).
1.4 In general, it is prudent to perform all field work with at least two people present. This increases safety and facilitates efficient data collection.
1.5 The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are for information only.
1.6 This standard does not purport to address all of the safety problems, 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.
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e1
Designation:D4700–91 (Reapproved 1998)
Standard Guide for
Soil Sampling from the Vadose Zone
This standard is issued under the fixed designation D 4700; 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 (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Paragraph 1.7 was added editorially January 1999.
1. Scope circumstances. This ASTM standard is not intended to repre-
sent or replace the standard of care by which the adequacy of
1.1 This guide addresses procedures that may be used for
a given professional service must be judged, nor should this
obtaining soil samples from the vadose zone (unsaturated
document be applied without consideration of a project’s many
zone). Samples can be collected for a variety of reasons
unique aspects. The word “Standard” in the title of this
including the following:
document means only that the document has been approved
1.1.1 Stratigraphic description,
through the ASTM consensus process.
1.1.2 Hydraulic conductivity testing,
1.1.3 Moisture content measurement,
2. Referenced Documents
1.1.4 Moisture release curve construction,
2.1 ASTM Standards:
1.1.5 Geotechnical testing,
D 420 Practice for Investigating and Sampling Soil and
1.1.6 Soil gas analyses,
Rock for Engineering Purposes
1.1.7 Microorganism extraction, or
D 653 Terminology Relating to Soil, Rock, and Contained
1.1.8 Pore liquid and soils chemical analyses.
Fluids
1.2 This guide focuses on methods that provide soil samples
D 1452 Practice for Soil Investigation and Sampling by
for chemical analyses of the soil or contained liquids or
Auger Borings
contaminants. However, comments on how methods may be
D 1586 Method for Penetration Test and Split-Barrel Sam-
modified for other objectives are included.
pling of Soils
1.3 This guide does not describe sampling methods for
D 1587 Method for Thin-Walled Tube Sampling of Soils
lithified deposits and rocks (for example, sandstone, shale, tuff,
D 2488 Practice for Description and Identification of Soils
granite).
(Visual-Manual Procedure)
1.4 In general, it is prudent to perform all field work with at
D 2607 Classification of Peats, Mosses, Humus, and Re-
least two people present. This increases safety and facilitates
lated Products
efficient data collection.
D 3550 Method for Ring-Lined Barrel Sampling of Soils
1.5 The values stated in inch-pound units are to be regarded
D 4083 Practice for Description of Frozen Soils (Visual-
as the standard. The SI units given in parentheses are for
Manual Procedure)
information only.
D 4220 Practice for Preserving and Transporting Soil
1.6 This standard does not purport to address all of the
Samples
safety problems, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3. Terminology
priate safety and health practices and determine the applica-
3.1 Definitions:
bility of regulatory limitations prior to use.
3.1.1 Except where noted, all terms and symbols in this
1.7 This guide offers an organized collection of information
guide are in accordance with the following publications. In
or a series of options and does not recommend a specific
order of consideration they are:
course of action. This document cannot replace education or
3.1.1.1 Terminology D 653.
experienceandshouldbeusedinconjunctionwithprofessional
3.1.1.2 Compilation of ASTM Standard Terminology, and
judgment. Not all aspects of this guide may be applicable in all
This guide is under the jurisdiction of ASTM Committee D-18 on Soil and
Rockand is the direct responsibility of Subcommittee D18.21 on Ground Water and Annual Book of ASTM Standards, Vol 04.08.
Vadose Zone Investigations. Compilation of ASTM Standard Terminology, Sixth edition,ASTM, 1916 Race
Current edition approved July 15, 1991. Published September 1991. St., Phila., PA 19103, 1986.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4700
3.1.1.3 Webster’s New Collegiate Dictionary. contaminants. Remedial or mitigating measures can be formu-
3.1.2 For definitions and classifications of soil related terms lated based on this information. This guide describes devices
used, refer to Practice D 2488 and Terminology D 653. Addi- and procedures that can be used to obtain vadose zone soil
tional terms that require clarification are defined in 3.2. samples.
3.2 Definitions of Terms Specific to This Standard:
5.2 Soil sampling is useful for the reasons presented in
3.2.1 cascading water—perched ground water that enters a
Section 1. However, it should be recognized that the general
well casing via cracks or uncovered perforations, trickling, or
method is destructive, and that resampling at an exact location
pouring down the inside of the casing.
is not possible.Therefore, if a long term monitoring program is
3.2.2 sludge—a water charged sedimentary deposit.
being designed, other methods for obtaining samples should be
3.2.2.1 Discussion—The water-formed sedimentary deposit
considered.
may include all suspended solids carried by the water and trace
elementsthatwereinsolutioninthewater.Sludgeusuallydoes
6. Criteria for Selecting Soil Samplers
not cohere sufficiently to retain its physical shape when
6.1 Important criteria to consider when selecting devices for
mechanical means are used to remove it from the surface on
vadose zone soil sampling include the following:
whichitdeposits,butitmaybebakedinplaceandbeadherent.
6.1.1 Type of sample: An encased core sample, an uncased
core sample, a depth-specific representative sample, or a
4. Summary of Guide
sample according to requirements of the analyses,
4.1 Sampling vadose zone soil involves inserting into the
6.1.2 Sample size requirements,
ground a device that retains and recovers a sample. Devices
6.1.3 Suitability for sampling various soil types,
and systems for vadose zone sampling are divided into two
6.1.4 Maximum sampling depth,
general groups, namely the following: samplers used in con-
6.1.5 Suitability for sampling soils under various moisture
junction with hand operated devices; and samplers used in
conditions,
conjunction with multipurpose or auger drill rigs. This guide
6.1.6 Ability to minimize cross contamination,
discusses these groups and their associated practices.
4.2 The discussion of each device is organized into three
6.1.7 Accessibility to the sampling site, and
sections, describing the device, describing sampling methods,
6.1.8 Personnel requirements.
and limitations and advantages of its use.
6.2 The sampling devices described in this guide have been
4.3 This guide identifies and describes a number of sam-
evaluated for these criteria. The results are summarized in Fig.
pling methods and samplers. It is advisable to consult available
1.
site-specific geological and hydrological data to assist in
determining the sampling method and sampler best suited for a
7. Sampling with Hand Operated Devices
specific project. It is also advisable to contact a local firm
7.1 These devices, that have mostly been developed for
providing the services required as not all sampling and drilling
agricultural purposes, include:
methods described in this guide are available nationwide.
7.1.1 Screw-type augers,
5. Significance and Use 7.1.2 Barrel augers,
7.1.3 Tube-type samplers,
5.1 Chemical analyses of liquids, solids, and gases from the
7.1.4 Hand held power augers, and
vadose zone can provide information on the presence, possible
7.1.5 Trench sampling with shovels in conjunction with
source, migration route, and physical-chemical behavior of
machine excavations.
7.2 The advantages of using hand operated devices over
drill rigs are the ease of equipment transport to locations with
Webster’s New Collegiate Dictionary, Fifth edition, 1977.
FIG. 1 Criteria for Selecting Soil Sampling Equipment
D4700
poor vehicle access, and the lower costs of setup and decon- the samples are not suitable for tests requiring undisturbed
tamination. However, a major disadvantage is that these samples, such as hydraulic conductivity tests. In addition, soil
devices are limited to shallower depths than drill rigs. structures are disrupted and small scale lithologic features
7.3 Screw-Type Augers: cannot be examined. Nevertheless, screw-type samplers are
7.3.1 Description—The screw or ship auger is essentially a still suitable for use in collecting samples for the purpose of
small diameter (for example, 1.5 in. (3.81 cm)) wood auger detecting contaminants. However, it is difficult to avoid trans-
from which the cutting side flanges and tip have been removed porting shallow soils downward when reentering a drill hole.
(1) (see Fig. 2(a)).According to the Soil Survey Staff (1), the When representative samples are desired from a discrete
spiral part of the auger should be about 7 in. (18 cm) long, with interval, the borehole must be made large enough to insert a
the distances between flights about the same as the diameter sampler and extend it to the bottom of the borehole without
(for example, 1.5 in.) of the auger. This facilitates measuring touching the sides of the borehole. It is suggested that a larger
the depth of penetration of the tool. Variations on this design diameter auger be used to advance and clear the borehole, then
include the closed spiral auger and the Jamaica open spiral a smaller diameter auger sampler be used to obtain the sample.
auger (2) (see Fig. 2(b) and Fig. 11(c)). The auger is welded Screw-type augers work better in wet, cohesive soils than in
onto a length of solid or tubular rod. The upper end of this rod dry, loose soils. Sampling in very dry (for example, powdery)
is threaded, to accept a handle or extension rods. As many soils may not be possible with these augers as soils will not be
extensions are used as are required to reach the target sampling retained on the auger flights.Also, if the soil contains gravel or
depth. The rod and the extensions are marked in even incre- rockfragmentslargerthanaboutonetenthoftheholediameter,
ments (for example, in 6-in. (15.24-cm) increments) above the drilling may not be possible (4).
base of the auger to aid in determining drilling depth. A
7.4 Barrel Augers:
wooden or metal handle fits into a tee-type coupling, screwed
7.4.1 Description—The barrel auger consists of a bit with
into the uppermost extension rod.
cutting edges welded to a short tube or barrel within which the
7.3.2 Sampling Method—For drilling, the auger is rotated
soil sample is retained, welded in turn to shanks. The shanks
manually. The operator may have to apply downward pressure
are welded to a threaded rod at the other end. Extension rods
tostartandembedtheauger;afterwards,theaugerscrewsitself
are attached as required to reach the target sampling depth.
into the soil. The auger is advanced to its full length, and then
Extensions are marked in increments above the base of the
pulled up and removed. Soil from the deepest interval pen-
tool.The uppermost extension rod contains a tee-type coupling
etrated by the auger is retained on the auger flights. A sample
forahandle.Theaugerisavailableincarbonsteelandstainless
can be collected from the flights using a spatula. A foot pump
steel with hardened steel cutting edges (5, 6).
operated hydraulic system has been developed to advance
7.4.2 Sampling Method—The auger is rotated to advance
augers up to 4.5 in. (11.43 cm) in diameter. This larger
the barrel into the ground. The operator may have to apply
diameter allows insertion of other sampling devices into the
downward pressure to keep the auger advancing. When the
drill hole, once the auger is removed, if desired (3).
barrel is filled, the unit is withdrawn from the soil cavity and a
7.3.3 Comments—Samples obtained with screw-type sam-
sample may be collected from the barrel.
plers are disturbed and are not truly core samples. Therefore,
7.4.3 Comments—Barrel augers generally provide larger
samples than screw-type augers. The augers can penetrate
shallow clays, silts, and fine grained sands (7). The augers do
The boldface numbers in parentheses refer to the list of references at the end of
not work well in gravelly soils, caliche, or semi-lithified
the text.
deposits. Samples obtained with barrel augers are disturbed
This reference is manufacturer’s literature, and it has not been subjected to
and are not core samples. Therefore, the samples are not
technical review.
FIG. 2 Screw Type Augers
D4700
suitable for tests requiring undisturbed samples, such as liners can also be used (6). Extension rods are available in 4
hydraulic conductivity tests. Nevertheless, the samplers are ft (1.22 m) lengths. The rods can be made from standard black
still suitable for use in collecting samples for the purpose of pipe, from lightweight conduit or from seamless steel tubing.
detecting contaminants. Because the sample is retained inside The extensions have evenly spaced marks to facilitate deter-
the barrel, there is less of a chance of mixing it with soil from mining sample depth. The regular barrel auger is suitable for
a shallower interval during insertion or withdrawal of the use in loam type soils.
sampler. The following are five common barrel augers: 7.4.7 Sand Augers—For dry, sandy soils it may be neces-
7.4.3.1 Post-hole augers (also called Iwan-type augers), sary to use a variation of the regular barrel auger that includes
7.4.3.2 Dutch-type augers, a specially-formed bit to retain the sample in the barrel (see
7.4.3.3 Regular or general purpose barrel augers, Fig. 5(c)). Sand augers with 2, 3, or 4-in. (5.08, 7.62, or
7.4.3.4 Sand augers, and 10.16-cm) diameters are available (5).
7.4.3.5 Mud augers. 7.4.8 Mud Augers—Another variation on the regular barrel
7.4.4 Post-Hole Augers—The most readily available barrel auger design is available for sampling wet, clayey soils. As
auger is the post-hole auger (also called the Iwan-type auger) shown in Fig. 5(d), the barrel is designed with open sides to
(8). As shown in Fig. 3, the barrel consists of two-part facilitate extraction of samples. The bits are the same as those
cylindrical leaves rather than a complete cylinder and is used on the regular barrel auger (6). Mud augers with 2, 3, or
slightly tapered toward the cutting bit. The taper and the 4-in. (5.08, 7.62, or 10.16-cm) diameters are available (5).
cupped bit help to retain soils within the barrel. The barrel is 7.5 Tube-Type Samplers:
available witha3to 12-in. (7.62 to 30.48-cm) diameter.
...
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