Authors: Edelbro, C


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Edelbro, C 2007, 'Observations and Modelling of Compressive Failures of Hard Rock Masses', in Y Potvin (ed.), Deep Mining 2007: Proceedings of the Fourth International Seminar on Deep and High Stress Mining, Australian Centre for Geomechanics, Perth, pp. 81-94,

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Observations from five case studies of induced compressive brittle failure fallouts are compared with different numerical modelling approaches, to determine the best non-calibrated approach. All case studies are situated in hard rock masses that are massive or sparsely fractured, at depths of 630-965 m below surface. The observed fallouts are compared with the results from numerical models in Examine2D and Phase2D. The objective is to identify which of the five numerical modelling approaches gives the best agreement with respect to location, depth, shape, and extent of the observed fallouts. None of the studied approaches give perfect agreement with the actual fallouts. This study demonstrates that when rock mass strength parameters are defined by either the Hoek-Brown or the Mohr-Coulomb criterion, the elastic and elastic-perfectly plastic models predict reasonably well actual fallout depth, although the extent of fallout is exaggerated and the shape incorrect. Therefore, a precise estimation can not be expected. When using the m = 0 approach, the results were in poor agreement with the observed fallout. The fallouts are significantly overestimated when applying the brittle-plastic model using instantaneous softening by cohesion and friction or cohesion weakening.

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Observations and Modelling of Compressive Failures of Hard Rock Masses C. Edelbro
94 Deep Mining 07, Perth, Australia

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