PRACTICAL ESTIMATES OF ROCK MASS STRENGTH

The Hoek-Brown failure criterion was originally developed for estimati ng the strengths of hard rock masses. Because of the lack of suitable alternatives, the criterion has been applied to a variety of rock mass es including very poor quality rocks, which could almost be classed as engineering soils. These applications have necessitated changes to th e original criterion. One of the principal problems has been the deter mination of equivalent cohesive strengths and friction angles to meet the demands of software written in terms of the Mohr-Coulomb failure c riterion. This paper summarises the interpretation of the Hoek-Brown f ailure criterion which has been found to work best in dealing with pra ctical engineering problems. (C) 1998 Elsevier Science Ltd.