Coggan, JS, Pine, RJ, Styles, TD & Stead, D 2007, 'Application of Hybrid Finite/Discrete Element Modelling for Back-Analysis of Rock Slope Failure Mechanisms', 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. 267-277, https://doi.org/10.36487/ACG_repo/708_15
Slope stability in fractured rock masses is of fundamental importance across a wide spectrum of applications
including landslides in coastal and hill areas, most rock quarry excavations, large scale open pits and civil
engineering projects for transportation corridors (principally road and rail). Numerical modelling, when
used appropriately, can be used to provide insight into potential failure mechanisms and assist the slope
design process. Back-analysis of previous slope instability provides valuable information regarding the
failure mechanism and, importantly, can provide valuable data for future design. A review of the results from
both previous and more recent modelling of the back-analysis of the 1967 failure of the West face at
Delabole Slate Quarry is used to provide the framework for evaluation of the application and benefits of
potential methods of slope stability analysis. This includes the results from more recent modelling using a
hybrid finite/discrete element modelling approach to model complex rock slope failure, including fracture
extension, progressive step-path failure and brittle fracture propagation.
Board, M., Chacon, E., Varona, P. and Lorig, L. (1996) Comparative analysis of toppling behaviour at Chuquicamata
open-pit mine, Chile. Inst. Min. Metall., Section A, 105, pp. A11-A21.
Brown, E.T. (1984) Stability of the western face, Delabole slate quarry. Report to Carnon Consolidated Tin Mines Ltd.
Brown, E.T., Richards, L.R. and Barr, M.V. (1977) Shear strength characteristics of the Delabole Slates. In Proc. Conf.
on Rock Engineering. Attewell, P.B. (ed). Newcastle upon Tyne: The University, pp. 33-51.
Clover, A.W. (1978) Some aspects of the rock excavations on the western face at Delabole slate quarry, Cornwall. MSc
dissertation, Imperial College, University of London, 99 p.
Coggan, J.S. and Pine, R.J. (1996) Application of distinct-element modelling to assess slope stability at Delabole slate
quarry, Cornwall, England. Trans. Inst. Min. Metall. Section A, 105, pp. A22-A30.
Coggan, J.S., Pine, R.J., Stead, D. and Rance, J.M. (2003) Numerical modelling of brittle rock failure using a combined
finite-discrete element approach: implications for rock engineering design. In ISRM 2003 – Technology
roadmap for rock mechanics. S. Afr. Inst. Min. Metall. Symposium Series S33, Vol. 1, pp. 211-218.
Corkum, A.G. and Martin, C.D. (2002) Discrete element analysis of the effect of a toe berm on a large rock slide. In
Proc. 55th Canadian geotechnical Conference, Niagara Falls. Canadian Geotechnical Society, Toronto, pp. 633-
Eberhardt, E., Stead, D. and Coggan, J.S. (2004) Numerical analysis of initiation and progressive failure in natural rock
slopes – the 1991 Randa rockslide. Int. J. Rock Mech. Min. Sci. 41 (1), pp. 69-87.
Elmo, D., Yan, M., Stead, D. and Rogers, S. (2007) 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. In Proceedings of the International Symposium on Rock slope Stability in Open Pit Mining and Civil
Engineering, Perth, Australia.
Application of Hybrid Finite/Discrete Element Modelling for Back-Analysis of Rock Slope Failure Mechanisms J.S. Coggan, et al.
276 Slope Stability 2007, Perth, Australia
Golder Associates (2007) FracMan Technology Group. www.fracman.golder.com
Hencher, S.R., Liao, Q.H. and Monaghan, B.G. (1996) Modelling slope behaviour for open-pits. Trans. Inst. Min.
Metall. Section A, 105, pp. A37-A47.
Hutchinson, B., Dugan, K. and Coulthard, M.A. (2000) Analysis of flexural toppling at Australian bulk minerals Savage
River mine. In Proc. GeoEng2000. Int. Conf. Geotech. Geol. Eng., Melbourne, CDROM, 6 p.
Itasca (1992) UDEC, Version 1.83 User’s Manual. Itasca Consulting.
Itacsa (2007) PFC3D, 3DEC. Itasca Consulting. www.itascacg.com.
Mencl, V. (1966) Mechanics of landslides with non-circular slip surfaces with special reference to the Vaiont slide.
Geotechnique; 16(4), pp. 329-337.
Pine, R.J., Coggan, J.S., Flynn, Z. and Elmo, D. (2006) The development of a comprehensive numerical modelling
approach for pre-fractured rock masses. Rock Mechanics and Rock Engineering, 39, 5, pp. 395-419.
Rockfield Software Ltd (2007) ELFEN User Manual, Swansea, UK. www.rockfield.co.uk.
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.
Starfield, J.L. and Cundall, P.A. (1988) Towards a methodology for rock mechanics modelling. Int. J. Rock Mech. Min.
Sci. and Geomech. Abst., 25, pp. 99-106.
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. (eds), Springer, Dordrecht,
Netherlands, pp. 131-142.
Stead, D., Eberhardt, E. and Coggan, J.S. (2006) Developments in the characterization of complex rock slope
deformation and failure using numerical modelling techniques. Engineering Geology, 83, pp. 217-235.
Stead, D., Coggan, J.S., Elmo, D. and Yan, M. (2007) Modelling brittle fracture in rock slopes: Experiences gained and
lessons learned. In Proceedings of the International Symposium on Rock Slope Stability in Open Pit Mining and
Civil Engineering, Perth, Australia.
Numerical Modelling of Rock Slope
Slope Stability 2007, Perth, Australia 277