Authors: Stead, D; Coggan, JS; Elmo, D; Yan, M

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Stead, D, Coggan, JS, Elmo, D & Yan, M 2007, 'Modelling Brittle Fracture in Rock Slopes - Experience Gained and Lessons Learned', in Y Potvin (ed.), Slope Stability 2007: Proceedings of the 2007 International Symposium on Rock Slope Stability in Open Pit Mining and Civil Engineering, Australian Centre for Geomechanics, Perth, pp. 239-252,

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Modelling of rock slopes has until recently traditionally considered failure as a yield/sliding dominated process. Brittle failure of rock during the rock slope failure was generally considered either unimportant or too difficult to model. The authors present a review of brittle rock fracture simulation in rock slope failure and discuss the approaches adopted to-date. Particular emphasis is given to the application of a hybrid finite-discrete element code incorporating fracture mechanics criteria. Simon Fraser University and Camborne School of Mines using this approach have almost fifteen years combined experience in simulating brittle rock fracture during rock slope failure including a wide variety of failure mechanisms. Initial modelling focused on back analysis of both major natural rock slides and engineered slopes. The rock slopes were modelled from an equivalent continuum to a rock debris pile. In the second phase of modelling an equivalent continuum was assumed and a total slope analysis simulated including development of the failure surface, brittle fracture of the rock mass and debris transport. The authors then considered the importance of limited discontinuity persistence and step-path failure involving intact rock fracture through rock bridges. Discrete pre-existing fractures of varied persistence were initially assumed with more recent rock slope analyses incorporating discrete fracture networks. The authors emphasise that the incorporation of intact rock fracture into the analysis of rock slopes is important in many rock slopes and essential if the failure of large open pit slopes or high mountain failures is to be realistically modelled.

Baczynski, N.R. (2000) StepSIM4 “Step-path” method for slope risks. GeoEng 2000, Melbourne, 6 p.
Bobet, A. and Einstein, H.H. (1998) Fracture coalescence in rock-type materials under uniaxial and biaxial
compression. Int. J. Rock. Mech. Min. Sci. 35, pp. 863-888.
Christianson, M.C., Board, M.P. and Rigby, D.B. (2006) UDEC simulation of triaxial testing of lithophysal tuff.
ARMA Paper 06-968, 41st US symposium on Rock Mechanics, Golden, Colorado, 8 p.
Coggan, J.S., Stead, D. and Eyre, J.M. (1998) Evaluation of techniques for quarry slope stability assessment. T.I.M.M. -
Section B 107, pp. B139-B147.
Couture, R., Evans, S.G., Locat, J., Hadjigeorgiou, J. and Antoine, P. (1999) A proposed methodology for rock
avalanche analysis. Slope Stability Engineering. Yagi, Yamagami and Jiang (editors), pp. 1369-1378.
Dershowitz, W., Lee, G., Geier, J. and Lapointe, P.R. (1998) FracMan: interactive Discrete feature Data Analysis.
Geometric Modelling and Exploration Simulation. User Documentation. Golder Associates Inc. Seattle -
Eberhardt, E., Stead, D. and Coggan, J.S. (2004a) Numerical analysis of initiation and progressive failure in natural
rock slopes - the 1991 Randa rockslide, Int. Journ. Rock Mech. 41, pp. 69-87.
Eberhardt, E., Stead, D., Karami, A. and Coggan, J.S. (2004b) Numerical Analysis of brittle fracture propagation and
step-path failure in massive rock slopes. Annual Canadian Geotech Conf. Quebec City.
Elmo, D. (2006) Evaluation of a hybrid FEM/DEM approach for determination of rock mass strength using a
combination of discontinuity mapping and fracture mechanics modelling, with particular emphasis on modelling
of jointed pillars. PhD Thesis. Camborne School of Mines, University of Exeter U.K.
Elmo, D., Vyazmensky, A., Stead, D. and Rance, J.R. (2007a) A hybrid FEM/DEM approach to model the interaction
between open-pit and underground block-caving mining. 1st Canada-US Rock Mechanics Symposium,
Vancouver. Taylor & Francis, London, Vol. 2, pp. 1287-1294.
Elmo, D., Yan, M., Stead, D. and Rogers, S. (2007b) The importance of intact rock bridges in the stability of high rock
slopes: Towards a quantitative investigation using an integrated numerical modelling – discrete fracture network
approach. Proc. Int. Symp. on Rock Slope Stability in Open Pit Mining and Civil Engineering. Perth, Australia.
Fairhurst, C. (2006) Keynote lecture, ARMA, 41st US Symposium on Rock Mechanics, Golden, Colorado.
Fracom (2007) Fracod Version 2.2. Fracom Ltd. Finland.
Golder Associates (2007) FracMan Technology Group.
Hoek, E. (1983) Strength of jointed rock masses, 23rd Rankine Lecture. Géotechnique 33(3), pp. 187-223.
Hoek, E., Grabinsky, M.S. and Diederichs, M.W. (1991) Numerical modelling for underground excavation design.
Trans. I.M.M. 100, pp. A22-A30.
Numerical Modelling of Rock Slope
Slope Stability 2007, Perth, Australia 251
Hoek, E.T., Wood, D. and Shah, S. (1992) A modified Hoek-Brown criterion for jointed rock masses. Proc. Rock
Characterization, Symp. Int. Soc. Rock Mech. Eurock ’92, pp. 209-214. London, Brit. Geotech. Soc.
International Society of Rock Mechanics (1981) ISRM suggested methods for rock characterization testing and
monitoring. Brown, E.T. (editor), Imprint Oxford: Pergamon, 211 p.
Itasca Ltd (2007) UDEC, PFC User Manuals. Itasca Consulting. .
Jennings, J.E. (1970) A mathematical theory for the calculation of the stability of slopes in open cast mines.
Proceedings Planning of Open Pit Mines, Johannesburg, pp. 87-102.
Kalenchuk, K.S., Diederichs, M.S. and McKinnon, S. (2006) Characterizing block geometry in jointed rock masses. Int.
J. Rock. Mech. Min. Sci. 43, pp. 1212-1225.
Karami, A. and Stead, D. (2007) Asperity degradation and damage in the direct shear test: A hybrid DEM/FEM
approach. Rock Mechanics and Rock Engineering (in press).
Kemeny, J. (2003) The time-dependent reduction of sliding cohesion due to rock bridges along discontinuities: A
fracture mechanics approach. Rock Mechanics and Rock Engineering. 36, pp. 27-38.
Kemeny, J. (2005) Time-dependent drift degradation due to the progressive failure of rock bridges along
discontinuities. Int. J. Rock. Mech. Min. Sci. 42, pp. 35-46.
Kim, B.H., Cai, M., Kaiser, P.K. and Yang, H.S. (2007) Estimation of block sizes for rock masses with non-persistent
joints. Rock Mech. Rock. Eng. 40, pp. 145-168.
Klerk, P.A. (2000) The finite element modelling of discrete fracture of quasi-brittle materials. PhD Thesis. University of
Pierce, M., Cundall, P., Potyondy, D. and Ivars, D.M. (2007) A synthetic rock mass model for jointed rock. Proceedings
1st Canada-U.S. Rock Mechanics Symposium. Vancouver. Vol. 1, pp. 341-349.
Potyondy, D. and Cundall, P. (2004) A bonded-particle model for rock. Int. J. Rock. Mech. Min. Sci. 41, pp. 1329-
Preh, P., Poisel, R. and Krastonov, J. (2002) Investigation of the failure mechanisms of hard, competent rock lying on a
soft, incompetent base by PFC2D. 1st International PFC Symposium. D.O. Potyondy and P.A. Cundall (editors),
Read, J.R.L. and Lye, G.N. (1984) Pit slope design methods: Bougainville copper open cut. Proceedings 5th
International Congress on Rock Mechanics, Melbourne, pp. C93-C98.
Rockfield (2007) ELFEN Code, Swansea, UK. .
Rocscience (2004) Phase2. Version Rocscience Inc., Toronto. .
Scavia, C. and Castelli, M. (1996) Analysis of the propagation of natural discontinuities in rock bridges. Proceedings
Eurock’96, Turin, pp. 445-451.
Singh, R.N. and Sun, G.X. (1989) Fracture mechanics applied to slope stability analysis. Proceedings Int. Symp. on
Surface Mining - Future Concepts, Nottingham, pp. 93-97.
Stacey, T.R. (2006) Considerations of failure mechanisms associated with rock slop instability and consequences for
stability analysis. J.S. Afr. Inst. Min Metall. 106, pp. 485-93.
Stacey, T.R., Xianbin, Y., Armstrong, R. and Keyter, G.J. (2003) New slope stability considerations for deep open pit
mines, J.S. Afr. Inst. Min Metall. 103, pp. 373-389.
Stead, D. and Coggan, J.S. (2006) Numerical modelling of rock slopes using a total slope failure approach. In
“Landslide from Massive Rock Slope Failure", Evans, S., Hermans, R. and Strom, A. (editors), Springer Verlag,
Dordrecht, Netherlands, pp.131-142.
Stead, D., Eberhardt, E. and Coggan, J.S. (2006b) Developments in the characterization of complex rock slope
deformation and failure using numerical modelling techniques. Eng. Geology. 83, pp. 217-235.
Stead, D., Yan, M., Elmo, D. and Coggan, J.S. (2006a) New developments in rock slope engineering: Implications for
open pit slope design. Proc. 59th Canadian Geotechnical Conference and 7th Joint CGS-IAH-CNC Groundwater
Speciality Conference, “Sea to Sky 2006”, Vancouver, October 1-4 2006, pp. 1054-1061.
Tang, C.A., Lin, P., Wong, R.H.C. and Chau, K.T. (2001) Analysis of crack coalescence in rock-like materials
containing three flaws – Part II: numerical approach. Int. J. Rock Mech. and Min. Sci. 38, pp. 925-939.
Tang, C.A., Xu, T., Yang, T.H. and Liang, Z.Z. (2004) Numerical investigation of mechanical behaviour of rock under
confining pressure and pore pressure. SINOROCK2004 symposium.
Wang, C., Tannant, D.D. and Lilly, P.A. (2003) Numerical analysis of the stability of heavily jointed rock slope using
PFC2D. Int. J. Rock Mech. and Min. Sci. 40, pp. 415-424.
Yan, M., Elmo, D. and Stead, D. (2007) Characterization of step-path failure mechanisms: A combined field based-
numerical modelling study. Proceedings 1st Canada-U.S. Rock Mechanics Symposium, Vancouver.
Modelling Brittle Fracture in Rock Slopes — Experience Gained and Lessons Learned D. Stead, et al.
252 Slope Stability 2007, Perth, Australia

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