STP402

    Influence of Rock Anisotropy and Time-Dependent Deformation on the Stress-Relief and High-Modulus Inclusion Techniques of In Situ Stress Determination

    Published: Jan 1966


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    Abstract

    Two of the most popular techniques used in the determination of in situ rock stresses are the stress-relief and high-modulus inclusion methods. Deformations and strains observed in the measuring instruments are usually interpreted on the assumption that the rock behaves as a homogeneous, isotropic, linearly elastic medium, a situation which is not even approximately correct in some practical cases.

    This paper presents a theoretical analysis of the influence of: (a) rock anisotropy, of the transversely isotropic kind, on the accuracy of values of in situ stresses determined from the usual isotropic analysis and (b) time-dependent rock deformation, represented as linear, isotropic, viscoelastic creep, on the stresses developed in high-modulus plugs. It is shown that significant errors (over 50 per cent for one stress-relief example chosen) may be introduced by neglecting these factors.

    Keywords:

    rock (material), rock mechanics, anisotropy, stress relieving, creep, inclusions, in situ, stress measurement, viscoelasticity


    Author Information:

    Berry, D S
    Research fellow, University of Nottingham,

    Fairhurst, C
    Professor and associate headPersonal member ASTM, School of Mineral and Metallurgical Engineering, University of Minnesota, Minneapolis, Minn.


    Paper ID: STP45142S

    Committee/Subcommittee: D18.12

    DOI: 10.1520/STP45142S


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