Authors: Edelbro, C


Cite As:
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,

Download citation as:   ris   bibtex   endnote   text   Zotero

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.

Diederichs, M. (1999) Instability of hard rock masses: the role of tensile damage and relaxation. PhD thesis,
Department of Civil Engineering, University of Waterloo, Waterloo, Canada, 566 p.
Diederichs, M., Kaiser, P.K. and Eberhardt, E. (2004) Damage initiation and propagation in hard rock tunnelling and
the influence of near-face stress rotation, Int. J. Rock Mech. Min. Sci, 41, pp. 785-812.
Diederichs, M.S., Carvalho, J.L. and Carter, T.G. (2007) A modified approach for prediction of strength and post yield
behaviour for high GSI rock masses in strong, brittle ground. Proceedings 1st Canada-US Rock Mechanic
symposium, Vancouver, Canada, 27-31 May, ISBN 978-0-415-44401-9.
Edelbro, C. (2006) Strength of hard rock masses: a case study, Technical report, Division of Mining and Geotechnical
Engineering, Luleå University of Technology, available online:
Hajiabdolmajid, V., Kaiser, P.K. and Martin, C.D. (2002) Modelling brittle failure of rock, Int. J. Rock Mech. Min. Sci,
Vol. 39, pp. 731-741.
Hoek, E., Kaiser, P.K. and Bawden, W.F. (1995) Support of underground excavations in hard rock, A.A.
Hoek, E. and Karzulovic, A. (2001) Rock mass properties for surface mines, Slope stability in surface mining,
Hustrulid, Carter, Van Zyl (eds), Society for Mining, Metallurgy, and Exploration Inc. (SME), Chapter 6.
Hoek, E., Carranza-Torres, C. and Corkum, B. (2002) Hoek-Brown failure criterion – 2002 edition. Proceedings 5th
North American Rock Mechanics Symposium and 17th Tunnelling Association of Canada Conference: NARMS-
TAC 2002, July 7-10, University of Toronto, pp. 267-271.
Kildemo, G.A. (1985) En bergmekanisk undersökelse av Kobbskaret Vegtunnel (in English: A rock mechanics
investigation in the Kobbskaret tunnel). MSc thesis, Norwegian Institute of Technology, Trondheim (in
Marinos, V., Marinos, P. and Hoek, E. (2005) The geological strength index: applications and limitations, Bull Eng
Geol Environ, 64, pp. 55-65.
Martin, C.D. (1997) 17th Canadian Geotechnical Colloquium: The effect of cohesion loss and stress path on brittle rock
strength, Can. Geotech. J. 34, pp. 698-725.
Martin, C.D., Read, R.S. and Martino, J.B. (1997) Observations of brittle failure around a circular test tunnel, Int. J.
Rock Mech. Min. Sci, Vol. 34 (7), pp. 1065-1073.
Martin, C.D. (1998) Estimating ground support for underground openings in hard rock, Bergmekanikdagen, SveBeFo,
Martin, C.D., Kaiser, P.K. and McCreath, D.R. (1999) Hoek-Brown parameters for predicting the depth of brittle failure
around tunnels. Canada Geotech. J. Vol. 36 (1), pp. 136-151.
Myrvang, A.M. (1991) Estimation of in situ compressive strength of rocks from in situ stress measurements in highly
stressed rock structures. Proceedings 7th ISRM Congress on Rock Mechanics, Aachen, W. Wittke (editor), A.A.
Balkema, Rotterdam, pp. 573-575.
Myrvang, A.M., Alnaes, L., Hansen, S.E. and Davik, K.I. (1997) Heavy spalling problems in road tunnels in Norway –
Long time stability and performance of sprayed concrete as rock support. International symposium on rock
support: applied solutions for underground structures, Lillehammer, 22-25 June 1997, Norwegian Society of
Chartered Engineers, Oslo, ISBN 82-91341-18-4.
Nilssen, P. (2004) Bergspenningsmålinger i Garpenberg Norra gruve, SINTEF bygg og miljø – Berg og geoteknikk.
STF22 F04110.
Rocscience Inc. (2005) Phase Version 6.020 - Finite Element Analysis for Excavations and Slopes., Toronto, Ontario, Canada.
Rocscience Inc. (2006) RocLab Version 1.021 – Rock mass strength analysis using the Hoek-Brown failure criterion., Toronto, Ontario, Canada.
Rocscience Inc. (2007) Examine Version 7.004 - 2D Stress Analysis for Underground Excavations., Toronto, Ontario, Canada.
Sjöberg, J. (2005) Rock mechanics analysis of the copper orebody, SwedPower Report 2050700-01 (confidential).
Sörheim, S. (1981) Bergtrykksvariasjoner og sikring i Heggura vegtunnel (in English: Rock stress changes and support
in the Heggura tunnel), M.Sc. thesis, Norwegian Institute of Technology, Trondheim (in Norwegian).
Observations and Modelling of Compressive Failures of Hard Rock Masses C. Edelbro
94 Deep Mining 07, Perth, Australia

© Copyright 2023, Australian Centre for Geomechanics (ACG), The University of Western Australia. All rights reserved.
View copyright/legal information
Please direct any queries or error reports to