HOEK-BROWN FAILURE CRITERION - 2002 EDITION

TLDR

The Hoek‑Brown failure criterion is widely used for rock masses worldwide, yet its application is hampered by uncertainties, especially in determining equivalent friction angles and cohesive strengths. This paper presents a recommended calculation sequence that resolves these issues. A Windows program, RocLab, was developed to solve and plot the equations described.

Abstract

The Hoek-Brown failure criterion for rock masses is widely accepted and has been applied in a large number of projects around the world. While, in general, it has been found to be satisfactory, there are some uncertainties and inaccuracies that have made the criterion inconvenient to apply and to incorporate into numerical models and limit equilibrium programs. In particular, the difficulty of finding an acceptable equivalent friction angle and cohesive strength for a given rock mass has been a problem since the publication of the criterion in 1980. This paper resolves all these issues and sets out a recommended sequence of calculations for applying the criterion. An associated Windows program called RocLab has been developed to provide a convenient means of solving and plotting the equations presented in this paper.