EMPIRICAL STRENGTH ENVELOPE FOR SHALE
DOI:
https://doi.org/10.11113/jt.v78.9505Keywords:
strength envelope, shale, Mohr-Coulomb criterion, Hoek-Brown criterionAbstract
Effectively, strength envelope describes behavior of rock when subjected to common stresses in construction, i.e. compressive, triaxial and tensile stresses. This study is aimed at investigating the strength envelope for shale, a sedimentary rock obtained from dam project site in Baram, Sarawak. Series of triaxial compression tests were carried out to obtain the strength envelope for the rock samples. For verification of failure criterion, uniaxial compression and Brazilian tests were also conducted on the rock samples. Results from the relevant tests were analysed using RocData software to obtain the strength envelope. Subsequently, Mohr-Coulomb and Hoek-Brown failure criterion are used to determine failure envelop for the rock samples. Based on the failure envelopes and the related strengths (i.e. compressive and tensile strength), suitability of both approach, in defining strength envelope for shale, is verified. The study shows that for highly laminated sedimentary rock like shale, Hoek-Brown criterion gave a more representative failure behaviour. The failure envelope clearly shown all the strength limits when the rock is subjected to triaxial, uniaxial and tensile stress, which is not clearly shown in the Mohr-Coulomb criterion. Therefore, Hoek-Brown criterion is a more appropriate method for describing strength envelope, as it able to show the limiting stresses when rock samples are subjected to common stresses in construction.References
Sivakugan, N., Shukla. S. K and Das. B. M. 2013. Rock Mechanics An Introduction. Taylor and Francais Group, United States of America.
Pettijohn F. J. 1975. Sedimentary Rocks. Third Edition, Harper and Brothers, New York.
Bates, R. L. and Jackson, J. A. 1987. Glossory of Geology, Second Edition, America Gelogical Institute, Falls Church, VA.
Potter, P. E., Maynard. J. B. and Pryor. W. A. 1980. Sedimentology of Shale. Springer Verlag, New York.
O’Brien, N. R. 1990. Significance of Lamination in Toarcian (Lower Jurassic) Shales from Yorkshire, Great Britain, Sedimentary Geology. Elsevier Science Publisher B.V., Amsterdam. 67: 25-34,
Labuz, J. F. and Zang. A. 2012. Mohr-Coulomb Failure Criterion. ISRM Suggested Method, Springer Verlag.
Zhao, J. 2005. Rock Mechanics for Civil Engineers. Swiss Federal Institute of Technology Lausanne, Switzerland.
Hoek, E. 1983. Strength of Jointed Rock Massess. 23rd Rankine Lecture, Geotechnique.
Lee. Y. K., Pietruszczak. S and Choi. B. H. 2012. Failure Criterion for Rocks Based on Smooth Approximations to Mohr-Coulomb and Hoek-Brown Failure Functions. International Journal of Rock Mechanics and Mining Sciences. 56: 146–160.
Hoek E and Brown E. T. 1988. The Hoek-Brown Failure Criterion – a 1988 Update, In: Curran J (ed) Proceedings of the 15th Canadian Rock Mechanics Symposium. University of Toronto.
Eberhardt E. 2012. The Hoek-Brown Failure Criterion. ISRM Suggested Method, Springer Verlag.
Ulusay, R. and Hudson, J. A 2007. The Complete ISRM Suggested Methods for Rock Characterization. Testing and Monitoring: 1974-2006, Iskeler Ankara, Turkey.
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