Determination of the Soil-Water Retention Curve and the Hydraulic Conductivity Function Using a Small Centrifuge

    Volume 34, Issue 5 (September 2011)

    ISSN: 0149-6115

    CODEN: GTJOAD

    Published Online: 12 July 2011

    Page Count: 10


    Martins Reis, Rodrigo
    State Univ. of Norte Fluminense Darcy Ribeiro,

    Nogueira Sterck, Wagner
    State Univ. of Norte Fluminense Darcy Ribeiro,

    Bastos Ribeiro, Artur
    State Univ. of Norte Fluminense Darcy Ribeiro,

    Dell’Avanzi, Eduardo
    Federal Univ. of Paraná,

    Saboya, Fernando
    State Univ. of Norte Fluminense Darcy Ribeiro,

    Tibana, Sergio
    State Univ. of Norte Fluminense Darcy Ribeiro,

    Roberto Marciano, Cláudio
    State Univ. of Norte Fluminense Darcy Ribeiro,

    Ramires Sobrinho, Rubens
    State Univ. of Norte Fluminense Darcy Ribeiro,

    (Received 15 November 2010; accepted 9 June 2011)

    Abstract

    An alternative methodology for direct determination of the soil-water retention curve (SWRC) and evaluation the hydraulic conductivity of the unsaturated soil was developed using a commercially available small centrifuge with a swinging type rotor assembly without in-flight instrumentation. The testing procedure consists of spinning up four initially saturated soil specimens until constant water content is achieved for a given angular speed. The soil – suction relationship is determined by relating the respective water content to the suction magnitude induced by the ceramic plate at the specimen’s base. The hydraulic conductivity of the unsaturated soil is estimated by dividing the cumulative flow rate measured at each angular speed by the respective hydraulic gradient applied at specimen’s middle height. This methodology was applied for evaluating the SWRC of a residual gneissic soil profile using both, undisturbed and remolded soil specimens. The results show good agreement to other well established methodologies such as filter-paper method, porous plate funnel and suction plate extractor. The determined unsaturated hydraulic conductivities magnitudes were compared to the theoretical predicted values given by the Mualem – van Genuchten model (van Genuchten, 1980) indicating good agreement. Overall, it can be concluded that the methodology proposed ensures good agreement in determining the SWRC and the hydraulic conductivity of studied soils.


    Paper ID: GTJ103590

    DOI: 10.1520/GTJ103590

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    Author
    Title Determination of the Soil-Water Retention Curve and the Hydraulic Conductivity Function Using a Small Centrifuge
    Symposium , 0000-00-00
    Committee D18