STP1014: Evaluation of Offshore In-Situ Vane Test Results

    Kolk, HJ
    Manager of engineering and staff engineer, Fugro Geotechnical Engineers B.V., AB Leidschendam,

    Hoope, Jt
    Manager of engineering and staff engineer, Fugro Geotechnical Engineers B.V., AB Leidschendam,

    Ims, BW
    Senior engineer, Fugro Ltd., Hemel Hempstead,

    Pages: 15    Published: Jan 1988


    Abstract

    An evaluation is presented of results from about 450 tests obtained with an offshore in-situ vane during geotechnical investigations in the North Sea and off the west coast of India. The soils tested are normally consolidated and included silts and clays with differing carbonate contents. The strength values of the in-situ vane are compared with strength results from triaxial tests, laboratory vane, and Torvane tests. These data are also correlated with in-situ test results obtained with the piezocone penetrometer. The in-situ vane shear strength data show a small scatter, and good agreement was found with unconsolidated undrained (UU) triaxial test results. The rate of post peak reduction in soil strength, measured on the vane shear strength-rotation curve, appears to depend on plasticity. Based on this study it is recommended that the vane be rotated to a minimum of 40° for very plastic clays to approximately 150° for clays with low plasticity, to determine post-peak strength behavior with great accuracy. It is suggested that the undrained shear strength values determined with the in-situ vane may be of greater value than other undrained shear strength measurements for axial pile design purposes. This study also yielded encouraging estimates of the coefficient of lateral stress at rest K0 based on in-situ vane and triaxial test data.

    Keywords:

    carbonate soils, clays, coefficient of lateral stress at rest, drilling, in-situ testing, in-situ vane, laboratory vane, ocean soils, shear strength, silt, triaxial tests


    Paper ID: STP10341S

    Committee/Subcommittee: D18.02

    DOI: 10.1520/STP10341S


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