ASTM D6031_D6031M-25
Standard Test Method for Nuclear Gauge Logging In Situ Water Content and Density of Soil and Rock in Drilled Access Holes or Trenches Using Horizontal, Slanted, and Vertical Access Tubes
| Označení normy: | ASTM D6031_D6031M-25 |
| Vydáno: | 15.10.2025 |
| Status: | Active |
| Počet stran: | 10 |
| Sekce: | 04.09 |
| Označení: | access tube; in-place density and water content; in situ density and water; nuclear methods; water mass per unit volume; winching equipment; |
1.1 This test method covers collection and comparison of logs of thermalized-neutron counts and back-scattered gamma counts along horizontal or vertical air-filled access tubes.
1.2 Access tubes are installed either by drilling access holes or digging a trench into the media being measured.
1.3 The purpose of the test method includes, but is not limited in application to, the monitoring engineered barriers at waste facilities and other research studies related to the motion of water and hydrocarbons through soil and rock.
1.4 Limitations—The sample heterogeneity and elemental composition of the material under test may affect the measurement of water content, density, or both. The apparatus shall be calibrated to the material under test at a similar density of dry soil or rock and in the similar type and orientation of access tube, or adjustments must be made in accordance with Annex A2.
1.4.1 Hydrogen, in forms other than water, as defined by Test Method D2216, will cause measurements in excess of the true water content. Some elements such as boron, chlorine, and minute quantities of cadmium, if present in the material under test, will cause measurements lower than the true water content. Some elements with atomic numbers greater than 20 such as iron (Fe) or other heavy metals may cause measurements higher than the true density value.
1.4.2 The measurement of water content and density using this test method exhibits spatial bias in that it is more sensitive to the material closest to the access tube. The density and water content measurements are necessarily an average of the total sample involved.
1.4.3 The sample volume for a water mass per unit volume measurement is approximately 0.048 m3 [1.7 ft3] at a water mass per unit volume of 200 kg/m3 [12.5 lbm/ft3]. The actual sample volume for water mass per unit volume is indeterminate and varies with the apparatus and the water content of the material. In general the greater the water content of the material, the smaller the measurement volume.
1.4.4 A density measurement has a sample volume of approximately 0.028 m3 [0.99 ft3]. The actual sample volume for density is indeterminate and varies with the apparatus and the density of the material. In general, the greater the density of the material, the smaller the measurement volume.
1.5 The in situ water content in mass per unit volume and the density in mass per unit volume of soil and rock at positions or in intervals along the length of an access tube are calculated by comparing the thermal neutron count rate and gamma count rates respectively to previously established calibration data.
1.6 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. Reporting the test results in units other than SI shall not be regarded as nonconformance with the standard.
1.6.1 The gravitational system of inch-pound units is used when dealing with inch-pound units. In this system, the pound (lbf) represents a unit of force (weight), while the unit for mass is slugs. The slug unit is not given unless dynamic (F=ma) calculations are involved.
1.6.2 The slug unit of mass is typically not used in commercial practice; that is, density, balances, and so on. Therefore, the standard unit for mass in this standard is either kilogram (kg) or gram (g) or both. Also, the equivalent inch-pound unit (slug) is not given/presented in parentheses.
1.6.3 The SI units presented for apparatus are substitutions of the inch-pound units, other similar SI units should be acceptable providing they meet the technical requirements established by the inch-pound apparatus.
1.6.4 It is common practice in the engineering/construction profession to concurrently use pounds to represent both a unit of mass (lbm) and of force (lbf). This practice implicitly combines two separate systems of units; the absolute and the gravitational systems. It is scientifically undesirable to combine the use of two separate sets of inch-pound units within a single standard. As stated, this standard includes the gravitational system of inch-pound units and does not use/present the slug unit for mass. However, the use of balances or scales recording pounds of mass (lbm) or recording density in lbm/ft3 shall not be regarded as nonconformance with this standard.
1.6.5 The terms density and unit weight are often used interchangeably. Density is mass per unit volume, whereas unit weight is force per unit volume. In this standard, density is given only in SI units. After density has been determined, the unit weight is calculated in SI or inch-pound units or both.
1.7 All observed and calculated values shall conform to the guide for significant digits and rounding established in Practice D6026.
1.7.1 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.
1.8 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. For specific hazards, see Section 8.
1.9 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.