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

Importancia y uso:

5.1 This test method is useful as a repeatable, nondestructive technique to monitor in-place density and water content of soil and rock along lengthy sections of horizontal, slanted, and vertical access holes or tubes. With proper calibration in accordance with Annex A1, this test method can be used to quantify changes in density and water content of soil and rock.

5.2 This test method is used in vadose zone monitoring, for performance assessment of engineered barriers at waste facilities, and for research related to monitoring the movement of water solutions and hydrocarbons through soil and rock. The nondestructive nature of the test allows repetitive measurements at a site and statistical analysis of results.

5.3 The fundamental assumptions inherent in the density measurement portion of this test method are that Compton scattering and photoelectric absorption are the dominant interactions of the gamma rays with the material under test.

5.4 The probe response, in counts, is converted to wet density by comparing the detected rate of gamma radiation with previously established calibration data (see Annex A1).

5.5 The probe count response may also be utilized directly for unitless, relative comparison with other probe readings.

5.5.1 For materials of densities higher than that of about the density of water, higher count rates within the same soil type relate to lower densities and, conversely, lower count rates within the same soil type relate to higher densities.

5.5.2 For materials of densities lower than the density of water, higher count rates within the same soil type relate to higher densities and, conversely, lower count rates within the same soil type relate to lower densities.

5.5.3 Because of the functional inflection of probe response for densities near the density of water, exercise great care when drawing conclusions from probe response in this density range.

5.6 The fundamental assumption inherent in the water content measurement portion of this test is that the hydrogen contained in the water molecules within the soil and rock is the dominant neutron thermalizing media, so increased water content of the soil and rock results in higher count rates of the water content system of the instrument.

Note 1: The quality of the result produced by this standard is dependent on the competence of the personnel performing it and the suitability of the equipment and facility used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some, but not all, of those factors.

Subcomité:

D18.21

Volúmen:

04.09

Número ICS:

71.040.50 (Physicochemical methods of analysis)

Palabras clave:

access tube; in-place density and water content; in situ density and water; nuclear methods; water mass per unit volume; winching equipment;