ASTM D4511-92(1996)
(Test Method)Standard Test Method for Hydraulic Conductivity of Essentially Saturated Peat
Standard Test Method for Hydraulic Conductivity of Essentially Saturated Peat
SCOPE
1.1 This test method covers the determination of the hydraulic conductivity (permeability) of essentially saturated, intact cylindrical specimens of peat when the hydraulic conductivity is greater than 1 10-7 m/s (1 10-5 cm/s). During the test, the specimens are contained in the core holder, or in right, regular cylindrical sections cut from the sampling tube in which they were originally obtained in the field.
1.2 Hydraulic conductivity is calculated on the basis of the measured constant flow rate through the specimen under constant head. For verification, flow rate determinations may be made at two or more values of constant head with corresponding calculations of hydraulic conductivity.
1.3 The values stated in SI units are to be regarded as the standard.
1.4 All observed and calculated values shall conform to the guide for significant digits and rounding established in Practice D6026.
1.4.1 The procedures used to specify how data are collected/recorded and calculated in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that should generally be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user's objectives, and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in analysis methods for engineering design.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D 4511 – 92 (Reapproved 1996)
Standard Test Method for
Hydraulic Conductivity of Essentially Saturated Peat
(Constant Head)
This standard is issued under the fixed designation D 4511; 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.
1. Scope 3. Terminology
1.1 This test method covers the determination of the hy- 3.1 Definitions—The definitions used in this test method
draulic conductivity (permeability) of essentially saturated, shall be in accordance with Terminology D 653.
intact cylindrical specimens of peat when the hydraulic con- 3.2 Definitions of Terms Specific to This Standard:
−5
ductivity is greater than 1 3 10 cm/s. During the test, the 3.2.1 deaerated (de-aired) water—water in which the
specimens are contained in the core holder, or in right, regular amount of dissolved gas (air) has been reduced.
cylindrical sections cut from the sampling tube in which they 3.2.2 flow rate—the quantity of water flowing through the
were originally obtained in the field. test specimen in a given period of time, when subjected to a
1.2 Hydraulic conductivity is calculated on the basis of the certain constant head differential.
measured constant flow rate through the specimen under 3.2.3 soaking—placement of a specimen in water for the
constant head. For verification, flow rate determinations may purpose of removing gas contained in the pore space, through
be made at two or more values of constant head with bouyancy, and replacement with water to cause saturation of
corresponding calculations of hydraulic conductivity. the specimen. This method of saturation does not effectively
1.3 The values stated in SI units are to be regarded as the remove all the gas contained in the specimen and does not
standard. prevent the continuous slow formation of gas from decompo-
1.4 This standard does not purport to address all of the sition under anaerobic conditions.
safety concerns, if any, associated with its use. It is the
4. Significance and Use
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- 4.1 Values of hydraulic conductivity determined by this test
method may be useful in making rough preliminary estimates
bility of regulatory limitations prior to use.
of the initial rates of drainage and compression of peat deposits
2. Referenced Documents
when the only effective stress increase on the deposit is that
2.1 ASTM Standards: resulting from a moderate, gradual lowering of the water table.
D 653 Terminology Relating to Soil, Rock, and Contained 4.2 Even under light, sustained loads, peat will undergo
Fluids dramatic volume changes which will influence (decrease) the
D 1587 Practice for Thin-Walled Tube Sampling of Soils hydraulic conductivity of the deposit by several orders of
D 2434 Test Method for Permeability of Granular Soils magnitude. This test method does not offer provisions for the
(Constant Head) determination of the relationship between hydraulic conduc-
D 2974 Test Methods for Moisture, Ash, and Organic Mat- tivity and the void ratios corresponding to increasing stress
ter of Peat and Other Organic Soils levels. Therefore, this test method is not suitable for applica-
D 4220 Practices for Preserving and Transporting Soil tions involving grade increases, such as embankment construc-
Samples tion or placement of access berms alongside drainage ditches.
2.2 NRC Document:
5. Interferences
Peat Testing Manual
5.1 Due to the generally fibrous texture and extremely high
compressibility of peat, present sampling technologies may not
This test method is under the jurisdiction of ASTM Committee D-18 on Soil
be able to obtain samples truly representative of the in situ
and Rock and is the direct responsibility of Subcommittee D18.04 on Hydrologic
conditions. It should therefore be recognized that disturbance
Properties of Soil and Rock.
caused during sampling and subsequent specimen preparation,
Current edition approved July 15, 1992. Published November 1992.
For further information, see “Methods for Measurement of Saturated Hydraulic together with natural variations in material composition, may
Conductivity,” Peat Testing Manual, Technical Memorandum No. 125, NRC
result in differences in the measured hydraulic conductivity of
Canada, pp. 80–84.
the specimens by several orders of magnitude.
Annual Book of ASTM Standards, Vol 04.08.
Available from National Research Council of Canada, Publications Section,
Building R-88, Ottawa, Ontario, Canada K1A 0R6.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 4511
5.2 There are no provisions in this test method for verifica- from the water. The tank shall be fitted with a suitable siphon.
tion of compliance with the fundamental test conditions listed
NOTE 1—Alternatively, deaerated water may be used, supplied from a
in 6.1.1 and 6.1.2. The assumption is made that these condi-
self-siphoning burette with attached inverted flask (minimum 750-mL
tions are satisfied if the flow rate, with time, is a linear
capacity), filled with deaerated water, and closed with a rubber stopper
relationship.
holding a tube, 15 cm (6 in.) long with the end cut diagonally.
5.3 The result of the test may be influenced by flow through
7.1.2 Upper Reservoir, of the same diameter as the sam-
open passages between the specimen and the rigid wall of the
pling cylinder and approximately 15 cm (6 in.) high.
specimen container. If such a condition is suspected or visually
7.1.3 Wire-Screen Support, fabricated from a ring clamp,
verified, notice thereof should be made in the test report.
with an inside diameter greater than the specimen cylinder and
covered with 425-μm (No. 40) wire mesh screening.
6. Fundamental Test Conditions
7.1.4 Circular Disk, cut from 425-μm (No. 40) wire mesh
6.1 The following ideal test conditions are prerequisite for
screening, with a diameter 0.1 cm smaller than that of the
laminar flow of water through porous media under constant-
specimen.
head conditions:
7.1.5 Funnel, with a head diameter at least 10 % larger than
6.1.1 Continuity of flow with no volume change during a
that of the specimen cylinder.
test,
7.1.6 Two 400-mL Beakers.
6.1.2 Flow with the void space saturated with water and no
7.2 Balances, having a precision (repeatability) of 60.01 g
air bubbles in the voids,
for weighing involving a mass of 200 g or less, 60.1 g for
6.1.3 Flow in the steady state with no changes in hydraulic
weighings of a mass between 200 and 1000 g, or 61 g for a
gradient, and
mass greater than 1000 g.
6.1.4 Direct proportionality of flow velocity with hydraulic
7.3 Miscellaneous Apparatus and Materials, such as ther-
gradients below certain values, after which flow becomes
mometers, clock with sweep second hand, soaking pan, pipe
turbulent.
cutters, trimming knife, cheese cloth, rubber bands, vinyl
6.2 All other types of flow involving partial saturation of
electrical tape, and micro-crystalline wax.
void space, turbulent flow, and unsteady state of flow are
transient in character and yield variable and time-dependent
8. Specimen Preparation
values of hydraulic conductivity; therefore, they require special
8.1 Specimens shall have a minimum diameter of 7.3 cm
test conditions and procedures.
(2.87 in.). The height-to-diameter ratio shall be between 1 and
7. Apparatus
2.
7.1 Flow Device—The flow device shall be as shown in Fig. 8.2 Prepare specimens from tube samples secured in accor-
1, fitted with the following components: dance with Practice D 1587, or other acceptable undisturbed
7.1.1 Constant-Head Filter Tank, as shown in Fig. 1 of Test sampling procedure, yielding cylindrical samples obtained in
Method D 2434, to supply water and to remove most of the air tight-fitting, rigid-metal core holders (Note 2). Preserve and
FIG. 1 Diagram for the Constant-Head System for Conductivity Measurement
D 4511
transport the specimens in accordance with the practice for 8.8 The ambient temperature during the test should not vary
Group D samples in Practices D 4220 (Note 3). by more than 63°C (65.5°F).
NOTE 2—It is generally recognized that samples of fibrous peat from
9. Test Procedure
shallow depths can be secured with the least amount of disturbance using
9.1 When it appears that a constant flow rate has been
a rotary type sampling device equipped with a thin cutting edge, serrated
5 attained, set a convenient time to start the flow rate measure-
wit
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