In-situ measurement of swelling characteristics of soils are required in soil physics and engineering studies. The combined use of neutron and gamma meters for making such measurements was evaluated. The regression of gamma ratio on neutron ratio was calculated by combining the calibration equations of the neutron and gamma meters with the swelling characteristics of the different soil layers in a transitional red-brown earth. The slope of the calculated regression of gamma ratio on neutron ratio was correlated with the extent of swelling in the soil layers. Close agreement was found between wet bulk densities calculated from measured gamma ratio and neutron ratio values at two adjacent sites. These densities were also very similar to the wet bulk densities obtained from the calculated regression lines of gamma ratio on neutron ratio for the transitional red-brown earth, allowing for soil heterogeneity of the field sites. Equations were derived for calculating the bulk density-moisture content relationship of a soil using the measured regression of gamma ratio on neutron ratio, and the calibration equations for the neutron and gamma meters. Equations were also developed for calculating the moisture content and the dry bulk density at a given depth in a swelling soil from a single gamma count. The use of the measured regressions of gamma ratio on neutron ratio to evaluate uniformity in swelling characteristics with depth in field soils is discussed. These regressions can also be used to determine the heterogeneity in swelling characteristics between field experimental sites of any soil. (Author/TRRL)

  • Availability:
  • Corporate Authors:

    Commonwealth Scientific & Industrial Research Org

    314 Albert Street
    East Melbourne, Victoria,   Australia 
  • Authors:
    • Jayawardane, N S
  • Publication Date: 1984

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 389-399
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00396101
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: ITRD, TRIS, ATRI
  • Created Date: Jan 31 1986 12:00AM