DOI https://doi.org/10.36487/ACG_rep/1815_20_Pierce
Cite As:
Fuenzalida, MA, Pierce, ME & Katsaga, T 2018, 'REBOP–FLAC3D hybrid approach to cave modelling', in Y Potvin & J Jakubec (eds),
Caving 2018: Proceedings of the Fourth International Symposium on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, pp. 297-312,
https://doi.org/10.36487/ACG_rep/1815_20_Pierce
Abstract:
The hybrid REBOP–FLAC3D approach allows prediction of the limits of the geomechanical zones defining the cave as a function of production. The results of the model can be used to derive estimates of: (i) caveability and caving rate, (ii) abutment stresses and cave loads, (iii) recovery and dilution entry, (iv) fragmentation, and (v) breakthrough timing and subsidence.
The approach simulates the caving process by explicitly modelling each isolated movement zone derived from REBOP into FLAC3D to determine the yielded zone and cave back associated with mass drawn. After one cycle of extraction, REBOP informs the location of the movement zones and the presence of air, if it exists, to the continuum FLAC3D model. FLAC3D solves stresses associated with the presence of these zones and estimates the yielded zone surrounding the cave. FLAC3D informs REBOP which zones (initially inactive) could now be mobilised. The procedure is repeated until the draw schedule used as an input in REBOP is finished.
Two of the main advantages of the hybrid approach include the capability of studying the potential impacts of isolated draw on cave growth and point loading on the extraction level, as well as the effect of including, explicitly, the airgap and mechanisms of fines migration and rilling on cave growth and subsidence. Two case studies are presented showing the capabilities of the hybrid approach.
Keywords: cave modelling, cave growth, subsidence, draw control, sinkhole, squeezing
References:
Barton, N & Kjærnsli, B 1981, ‘Shear strength of rockfill’, Journal of the Geotechnical Engineering Division, Proceedings of the American Society of Civil Engineers, vol. 107, no. GT7, proceedings paper 16374, pp. 873–891
Beck, DA, Sharrock, G & Capes, G 2011, ‘A coupled DFE-Newtonian cellular automata cave initiation, propagation and induced seismicity’, Proceedings of the 45th US Rock Mechanics/Geomechanics Symposium, American Rock Mechanics Association, Alexandria.
Board, M, Pierce, M, Lorig, L, Jakubec, J & Campbell, R 2006, Complementary Geotechnical Studies for Conceptual Design of an Underground Mine at Chuquicamata, report to Codeclo Chile – División Codelco Norte.
Board, M & Pierce, M 2009, ‘A review of recent experience in modelling of caving’, International Workshop on Numerical Modelling for Underground Mine Excavation Design, June 28 2009, Asheville, in conjunction with the 43rd US Rock Mechanics Symposium.
Brown, ET 2003, Block Caving Geomechanics, 2nd edn, Julius Kruttschnitt Minerals Research Centre, The University of Queensland, Brisbane.
Hoek, E, Carranza-Torres, C & Corkum, B 2002, ‘Hoek-Brown failure criterion – 2002 edition’, Proceedings of the 5th North American Rock Mechanics Symposium and the 17th Tunnelling Association of Canada Conference, University of Toronto Press, Toronto, pp. 267–273.
Duplancic, P & Brady, BH 1999, ‘Characterization of caving mechanisms by analysis of seismicity and rock stress’, Proceedings of the 9th International Congress on Rock Mechanics, vol. 2, A.A. Balkema, Rotterdam, pp. 1049–1053.
Itasca Consulting Group 2017, FLAC3D — Fast Lagrangian Analysis of Continua in Three Dimensions, version 6.0, computer software, Itasca Consulting Group, Minneapolis.
Pappas, D & Mark, C 1993, Behavior of Simulated Longwall Gob Material, report of investigations 9458, United States Bureau of Mines, Washington, D.C.
Pierce, ME 2010, A Model for Gravity Flow of Fragmented Rock in Block Caving Mines, PhD thesis, The University of Queensland, Brisbane.
Pierce, ME 2013, ‘Numerical modeling of rock mass weakening, bulking and softening associated with cave mining’, American Rock Mechanics Association E-newsletter, Spring 2013, no. 9.
Sainsbury, BL, Sainsbury, DP & Pierce, ME 2011, ‘A historical review of the development of numerical cave propagation simulations’, in DP Sainsbury, R Hart, C Detournay & M Nelson (eds), Proceedings of the 2nd International FLAC/DEM Symposium, Itasca International Inc, Minneapolis, paper 02-01.
Sainsbury, BL 2012, A Model for Cave Propagation and Subsidence Assessment in Jointed Rock Masses, PhD thesis, The University of New South Wales, Sydney.