..., as extended to rock mass strength. The parameters mi and s c are not material properties if the exponent is fixed at 0.5. Published values of mi can be misleading as mi does not appear to be related to rock type. The Hoek-Brown criterion can be generalised by allowing the exponent to vary. This change...

... the application of the solution to the construction of the GRC using the closed-form solution is discussed and results compared with those from the classical Hoek-Brown criterion as implemented in the finite difference code FLAC 3D . INTRODUCTION Estimation of the support required to stabilize excavations...

...- diate principal stress. It is more acceptable to assume that the intermediate principal stress will have a negligible influenceon yield conditions for intact rock than it is for jointed rock (Reik and Zacas 1978). 3 THE HOEK-BROWN CRITERION Among those available criteria listed in Table 1, the only one...