A New Free-Free Resonant Column Device for Measurement of Gmax and Dmin at Higher Confining Stresses

    Volume 28, Issue 2 (March 2005)

    ISSN: 0149-6115

    CODEN: GTJOAD

    Published Online: 5 January 2005

    Page Count: 8


    Kalinski, ME
    Assistant Professor, University of Kentucky, Lexington, KY

    Thummaluru, MSR
    Geotechnical Engineer, Alexcom and Associates, Fredricksburg, VA

    (Received 8 August 2003; accepted 13 August 2004)

    Abstract

    The fixed-free resonant column device has traditionally been used to measure shear modulus in laboratory soil and rock specimens. It is a proven method that provides measurements over a range of shear strain and effective confining stress (σ′o), but the test relies on a specialized system of coils and magnets. The free-free resonant column device is a simpler device that allows for measurement of small-strain shear modulus (Gmax) and small-strain material damping (Dmin). However, σ′o in the free-free device has traditionally been limited to a maximum attainable vacuum pressure of around 80 kPa, because the test has not been configured in a pressurized cell. Therefore, a new free-free device was developed to allow measurements in a pressurized cell with σ′o greater than 80 kPa, while remotely exciting the specimen with a rotary solenoid. Test results demonstrate its potential for measuring Gmax and Dmin under higher levels of σ′o that are more representative of in situ conditions.


    Paper ID: GTJ12187

    DOI: 10.1520/GTJ12187

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    Author
    Title A New Free-Free Resonant Column Device for Measurement of Gmax and Dmin at Higher Confining Stresses
    Symposium , 0000-00-00
    Committee D18