Effect of discontinuity dip direction on hard rock pillar strength

Transactions of the Society for Mining, Metallurgy, and Exploration , 2018, Vol. 344, No. 1, pp. 25-30

Jessu, K.V.; Kostecki, T.R.; Spearing, A.J.S.; Esterhuizen, G.S.

DOI: https://doi.org/10.19150/trans.8745

Discontinuities are geologic occurrences in rock and when present within a pillar, reduce the strength of the pillar. Empirical formulas that are commonly used to determine pillar strength do not explicitly take into account the presence of discontinuities and thus can overestimate the pillar strength. The effect of discontinuities on the strength of pillars has been investigated using numerical models, but in these models, the discontinuity strike was parallel with the pillar faces. In this study, fully three-dimensional hard rock pillars were simulated using numerical modeling to understand the effect of the discontinuity dip direction on square and rectangular hard rock pillars. Based on the results, recommendations to assess a pillar’s strength in the presence of a discontinuity are discussed.