ASTM D2434-22

ABSTRACT This test method covers the determination of the coefficient of permeability by a constant-head method for the laminar flow of water through granular soils. The procedure is to establish representative values of the coefficient of permeability of granular soils that may occur in natural deposits as placed in embankments, or when used as base courses under pavements. The different apparatus used in determining the granular soil permeability are presented. The methods in preparing the test specimen are presented in details. The testing and calculation procedure for granular soil permeability determination are presented. SIGNIFICANCE AND USE 5.1 These test methods are used to measure one-dimensional vertical flow of water through initially saturated coarse-grained, pervious (that is, free-draining) soils under an applied hydraulic gradient. Hydraulic conductivity of coarse-grained soils is used in various civil engineering applications. These test methods are suitable for determination of hydraulic conductivity for soils with k > 10–7 m/s. Note 2: Clean coarse-grained soils that are classified using Practice D2487-17 as GP, GW, SP, and SW can be tested using these test methods. Depending on fraction and characteristics of fine-grained particles present in soils, these test methods may be suitable for testing other soil types with fines content greater than 5 % (for example, GP-GC, SP-SM). 5.2 Coarse-grained soils are to be tested at a void ratio representative of field conditions. For engineered fills, compaction specification can be used to provide target test conditions, whereas for natural soils, field testing of in-situ density can be used to provide target test conditions. 5.3 Use of a dual-ring permeameter is included in these test methods in addition to a single-ring permeameter for the rigid wall test apparatus. The dual-ring permeameter allows for reducing potential adverse effects of sidewall leakage on measured hydraulic conductivity of the test specimens. The use of a plate at the outflow end of the specimen that contains a ring with a diameter smaller than the diameter of the permeameter and the presence of two outflow ports (one from the inner ring, one from the annular space between the inner ring and the permeameter wall) allows for separating the flow from the central region of the test specimen from the flow near the sidewall of the permeameter. Note 3: Sidewall leakage has been reported to have significant influence on flow conditions for coarse-grained soils due to presence of larger voids at the boundary and higher void ratio in this region of the specimen. Three modificat... SCOPE 1.1 These test methods cover laboratory measurement of the hydraulic conductivity (also referred to as coefficient of permeability) of water-saturated coarse-grained soils (for example, sands and gravels) with k > 10–7 m/s. The test methods utilize low hydraulic gradient conditions. 1.2 This standard describes two methods (A and B) for determining hydraulic conductivity of coarse-grained soils. Method A incorporates use of a rigid wall permeameter and Method B incorporates the use of a flexible wall permeameter. A single- or dual-ring rigid wall permeameter may be used in Method A. A dual-ring permeameter may be preferred over a single-ring permeameter when adverse effects from short-circuiting of permeant water along the sidewalls of the permeameter (that is, prevent sidewall leakage) are suspected by the user of this standard. 1.3 The test methods are used under constant head conditions. 1.4 The test methods are used under saturated soil conditions. 1.5 Water is used to permeate the test specimen with these test methods. 1.6 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. Note 1: Hydraulic conductivity has traditionally been reported in cm/s in the US, even though the official SI unit for hydraul...