Estimating the Mechanical Properties of Rock Masses

Reliably estimating the mechanical properties of discontinuous rock masses remains one of the greatest challenges faced in the discipline of rock mechanics. This paper discusses the development, uses and limitations of the Hoek–Brown empirical rock and rock mass strength criterion, some of the extensions made to the criterion by others, and associated methods of estimating rock mass deformabilities. Extreme care must be taken in extending the use of these approaches beyond reasonable limits. Modern methods of predicting the engineering responses of rocks and rock masses using advanced numerically-intensive methods provide a sound and promising basis for developing improved understandings of the engineering responses of rock masses and for making improved predictions of rock mass properties and performance.