Automatic Back-Pressure Saturation Device for Triaxial Testing

    Volume 13, Issue 2 (June 1990)

    ISSN: 0149-6115

    CODEN: GTJOAD

    Page Count: 6


    Brandon, TL
    Assistant professor of civil engineering and university distinguished professor, Virginia Polytechnic Institute and State University, Blacksburg, VA

    Duncan, JD
    Assistant professor of civil engineering and university distinguished professor, Virginia Polytechnic Institute and State University, Blacksburg, VA

    Cadden, AW
    Senior staff engineer, Schnabel Engineering Associates, Richmond, VA

    Abstract

    If back pressures are applied to unsaturated triaxial specimens too rapidly, the specimens may be overconsolidated by the temporary application of effective stresses that are higher than intended. This is dangerous because the strengths of the specimens will be higher than they would be without this inadvertent overconsolidation. An automated device has been developed to ensure that the specimen will not be overconsolidated during saturation. This device continuously monitors the maximum effective stress in the specimen and optimizes the rate at which the cell pressure and back pressure can be increased without exceeding an allowable effective stress at any point in the specimen. Tests were performed on three soils with different grain sizes and degrees of saturation to investigate the effectiveness of the device under varying test conditions. The tests show that the device is capable of applying back pressures with a minimum of operator attention, and that it eliminates the possibility of inadvertently overconsolidating specimens during back-pressure application.


    Paper ID: GTJ10697J

    DOI: 10.1520/GTJ10697J

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    Author
    Title Automatic Back-Pressure Saturation Device for Triaxial Testing
    Symposium , 0000-00-00
    Committee D18