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Standard Test Method for Measurement of the Permeability of Unsaturated Porous Materials by Flowing Air (Withdrawn 2022)
Automaticky preložený názov:
Štandardná skúšobná metóda na meranie priepustnosti poréznych materiálov prostredníctvom prúdenia vzduchu
NORMA vydaná dňa 1.5.2013
Označenie normy: ASTM D6539-13
Poznámka: NEPLATNÁ
Dátum vydania normy: 1.5.2013
Kód tovaru: NS-35553
Počet strán: 10
Približná hmotnosť: 30 g (0.07 libier)
Krajina: Americká technická norma
Kategória: Technické normy ASTM
Keywords:
airflow, flexible wall permeameter, permeability, permeameter, permeability, rigid wall permeameter, ICS Number Code 13.080.20 (Physical properties of soil)
Significance and Use | ||||||||||||||||||||||||||||||||||
4.1 This test method applies to the one-dimensional laminar (viscous) flow of air in porous materials such as soil. 4.2 The degree of saturation of the
specimen shall be less than that which would produce significant
internal transport of pore water or alter the continuity of air
voids under the applied gradients. The maximum permissible degree
of saturation must be evaluated by an experienced analyst. In no
instance shall the specimen be so saturated that pore water appears
at the exit of the permeameter cell during the test.
4.3 This test method is based on the assumption that the rate of mass flow through the specimen is constant with time. 4.4 The permeability of porous
materials may be strongly dependent on a variety of physical
properties including the void ratio, the degree of saturation, and
percent and direction of compaction. It is beyond the scope of this
test method to elaborate upon these dependencies. Rather, this test
method is intended to be a measurement technique for determining
the permeability under a certain set of laboratory conditions. It
is the responsibility of the test requestor to specify which soil
parameters must be controlled to ensure a valid extension of the
test results to field conditions.
4.5 Calculation of the permeability using Darcy’s law requires laminar flow conditions through the soil specimen. The conditions for laminar flow shall be evaluated by plotting the volumetric flow rate of air through the specimen against the pressure drop across the specimen. If the individual test points lie within 25 % of a straight line passing through the origin, then laminar flow conditions are present and Darcy's law may be used to calculate the permeability. 4.6 This test method covers the use
of two different types of permeameter cells (flexible and rigid
wall permeameters) and two types of air flow regulation (mass flow
control and pressure control).
4.7 A flexible wall permeameter is the preferred means for confining the test specimen in accordance with Test Methods D5084, D4525, and D4767. This test method may still be performed using a rigid wall permeameter, but all reference to effective confining stress and the permeameter cell pressure system shall then be disregarded. 4.8 For some specimens, the permeability will be strongly dependent on the effective confining stress due to porosity reduction. Whenever possible, the requestor shall specify the field overburden conditions at which this test method is to be performed. In some specimens, this stress will vary significantly with flow in an indeterminate way. All specimens shall be evaluated for this effect by performing this test method at two or more different confining stress values when a flexible wall permeameter is used. 4.9 This test method is intended to support soil remediation operations such as: soil vapor extraction, air sparging, backfilling of soils in utility trenches, and similar engineering activities. 4.10 The correlation between results obtained with this test method and in situ field measurements has only been partially established. The small laboratory specimen used in this method may not be representative of the distributed condition on-site due to vadose zone fluctuations, changes in soil stratigraphy, and so forth. For this reason, caution should be used by qualified personnel when applying laboratory test results to field situations. 1.1 This test method covers
laboratory determination of the coefficient of permeability for the
flow of air through unsaturated porous materials.
1.2 This test method may be used with intact or compacted coarse grained soils, silts, or lean cohesive soils that have a low degree of saturation and that have permeability between 1.0 × 10-15 m2 (1.01 millidarcy) and 1.0 × 10-10 m2 (101 darcy). 1.3 The values stated in SI units are to be regarded as standard. 1.3.1 By tradition in U.S. practice, the permeability of porous media is reported in units of darcy, although the SI unit for permeability is m2. 1.4 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026. 1.4.1 For the purpose of comparing a measured or calculated value with specified limits, the measured or calculated value shall be rounded to the same precision as the specified limits. 1.4.2 The procedures used to specify how data are collected/recorded or calculated, in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user's objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in 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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2. Referenced Documents | ||||||||||||||||||||||||||||||||||
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