ASTM D4511-11(2020)

4.1 Values of hydraulic conductivity determined by this test method may be useful in making rough preliminary estimates of the initial rates of drainage and compression of peat deposits when the only effective stress increase on the deposit is that resulting from a moderate, gradual lowering of the water table.

4.2 Even under light, sustained loads, peat will undergo dramatic volume changes that influence (decrease) the hydraulic conductivity of the deposit by several orders of magnitude. This test method does not offer provisions for the determination of the relationship between hydraulic conductivity and the void ratios corresponding to increasing stress levels. Therefore, this test method is not suitable for applications involving grade increases, such as embankment construction or placement of access berms alongside drainage ditches.

4.3 Undisturbed specimens from apparently homogeneous peat deposits at the same location often exhibit significantly different hydraulic conductivity properties due to variations in material composition and sampling procedure.

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.2 For verification, flow rate determinations may be made at two or more values of constant head with corresponding calculations of hydraulic conductivity.

1.3 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses are provided for information only and are not considered standard.

1.4 All observed and calculated values shall conform to the guide for significant digits and rounding established in Practice D6026.

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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.6 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.