Authors: Venter, J; Purvis, C; Hamman, J


Cite As:
Venter, J, Purvis, C & Hamman, J 2016, 'Hoek–Brown mi estimation — a comparison of multistage triaxial with single stage triaxial testing', in PM Dight (ed.), APSSIM 2016: Proceedings of the First Asia Pacific Slope Stability in Mining Conference, Australian Centre for Geomechanics, Perth, pp. 289-299,

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This paper presents an argument that the current accepted practice of obtaining the intact Hoek–Brown parameters σci and mi from single stage triaxial tests suffers from several drawbacks, for instance, many specimens are needed to obtain a single estimate of σci and mi, and specimen variability can result in difficult to interpret regression analyses. A solution is proposed in that multistage triaxial testing can be used, provided the peak compressive strengths needed are based on servo controlled termination of each testing stage based on real-time measurement of Poisson’s ratio. The paper proposes a procedure for determining peak strength for each stage and tests the proposed method against single stage triaxial tests. The paper finds that the approach is valid for practical purposes but also recommends further work.

Keywords: triaxial test, single stage, multi stage, Hoek-Brown

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