Analysing the modified Hoek–Brown failure criteria using Hungarian granitic rocks

Abstract

The Hoek–Brown empirical failure envelope is widely used for determining the strength of brittle intact rock and rock masses. One of the two independent parameters in the formula is the Hoek–Brown’s material constant (mi), which has several uncertainties, since it relies on a set of triaxial tests. The present paper introduces a new approach to determine the material constant by using the uniaxial compressive strength, rather than the triaxial strength values. This newly calculated Hoek–Brown parameter was cross-checked by using published data and new experimental data obtained from granitic samples of Bátaapáti (Hungary). Based on these new equations new material constants are suggested to be used in calculations.