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Energies 2018, 11(11), 3229;

Laboratory and Numerical Investigation on Strength Performance of Inclined Pillars

Western Australian School of Mines, Curtin University, Kalgoorlie 6430, Australia
Author to whom correspondence should be addressed.
Received: 8 October 2018 / Revised: 26 October 2018 / Accepted: 19 November 2018 / Published: 21 November 2018
(This article belongs to the Section Energy Sources)
PDF [5946 KB, uploaded 21 November 2018]


Pillars play a critical role in an underground mine, as an inadequate pillar design could lead to pillar failure, which may result in catastrophic damage, while an over-designed pillar would lead to ore loss, causing economic loss. Pillar design is dictated by the inclination of the ore body. Depending on the orientation of the pillars, loading can be axial (compression) in horizontal pillars and oblique (compression as well as shear loading) in inclined pillars. Empirical and numerical approaches are the two most commonly used methods for pillar design. Current empirical approaches are mostly based on horizontal pillars, and the inclination of the pillars in the dataset is not taken into consideration. Laboratory and numerical studies were conducted with different width-to-height ratios and at different inclinations to understand the reduction in strength due to inclined loading and to observe the failure mechanisms. The specimens’ strength reduced consistently over all the width-to-height ratios at a given inclination. The strength reduction factors for gypsum were found to be 0.78 and 0.56, and for sandstone were 0.71 and 0.43 at 10° and 20° inclinations, respectively. The strength reduction factors from numerical models were found to be 0.94 for 10° inclination, 0.87 for 20° inclination, 0.78 for 30° inclination, and 0.67 for 40° inclination, and a fitting equation was proposed for the strength reduction factor with respect to inclination. The achieved results could be used at preliminary design stages and can be verified during real mining practice. View Full-Text
Keywords: pillars; inclination; oblique loading; width-to-height ratio; strength reduction factors pillars; inclination; oblique loading; width-to-height ratio; strength reduction factors

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Jessu, K.V.; Spearing, A.J.S.; Sharifzadeh, M. Laboratory and Numerical Investigation on Strength Performance of Inclined Pillars. Energies 2018, 11, 3229.

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