A quantitative comparison of six rock failure criteria

The material parameters of six failure criteria were optimized for eight rocks so that least mean standard deviation misfits could be obtained. A comparison of these misfits revealed the enhancements that are possible in defining rock failure criteria as non-linear in p - q space and dependent on intermediate principal stress. The new HBMN criterion which incorporates both of these features in one failure criterion consequently gave the overall least misfit in this study. Finally, it should be noted that the HBMN criterion uses exactly the same material parameters as the HB criterion. Nevertheless, the best fit parameters for both models given in Table 3 are somewhat different: The unconfined compressive strength σc i and the intact rock parameter mi are generally smaller within the HBMN criterion. In the case of the unconfined compressive strength this is certainly a desirable consequence. The intact rock parameters of both models equally fit the domains proposed by Hoek et al. [3]. In practical applications, the HBMN criterion can be used in the same way as the HB criterion, not only describing the behavior of intact rock, but also the behavior of rock masses. © 2008 Elsevier Ltd. All rights reserved.