Abstract

Over the past decades, many pillar strength relationships have been formulated from empirical observation of stable and failed case histories. These empirically derived equations are still widely adopted as a general technique for estimating pillar strength and simplified methods for evaluating the pillar stress (i.e., tributary area method). These generally accepted assessment methods might result in non-fully optimized solutions in terms of safe and, at the same time, economical designs. Numerical methods provide a better alternative to evaluate the mechanical behaviour of pillars in the context of progressive failure and, in turn, for a proper definition of the safety margins. In this paper, we propose using numerical modelling to determine the pillar strength through 3D analyses. An advanced constitutive model (Hoek-Brown with softening) is adopted to predict brittle mechanisms in rock masses. The results are compared with those obtained through empirical methods, providing insights about the implications of adopting empirical pillar design methods.

This paper was presented at the 57th U.S. Rock Mechanics/Geomechanics Symposium, Atlanta, Georgia, USA, June 2023, and is available here:
Assessment of Empirical Methods-Based Pillar Strength Estimation Through Numerical Modelling - Cammarata, et al. (2023); https://eposter.at/ISRM2023/data/PDF/1754.pdf

See also