Authors: Ovalle, C; Girumugisha, G; Cantor, D; Ouellet, S

Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2335_16

Cite As:
Ovalle, C, Girumugisha, G, Cantor, D & Ouellet, S 2023, 'Size effects assessment of mine waste-rock shear strength combining numerical, laboratory and in situ approaches', in PM Dight (ed.), SSIM 2023: Third International Slope Stability in Mining Conference, Australian Centre for Geomechanics, Perth, pp. 291-300, https://doi.org/10.36487/ACG_repo/2335_16

Download citation as:   ris   bibtex   endnote   text   Zotero


Abstract:
With the aim of performing stability analyses of waste-rock (WR) piles, the critical shear strength of loose WR material must be characterised. However, due to the presence of oversized rock clasts, shear tests can only be carried out on small samples prepared using grading scaling techniques. In order to test samples similar to the field material, particle size reduction should be minimised. Considering a testing device able to handle samples of characteristic size , the material should be scaled down to a maximum particle size , given by the minimum sample aspect ratio allowing a representative elementary volume (REV). However, worldwide geotechnical standards do not agree on minimum values, and its effects on the mechanical behaviour of coarse samples remain poorly understood. Based on numerical, laboratory and large in situ shear testing approaches, this paper presents a comprehensive study on the effects of sample size and grading on the critical shear strength of WR materials. The main objectives are to analyse the minimum required for a REV in shear testing and to study the suitability of the scalping technique to assess the critical shear strength of mine WR. We study this topic through three methodologies: (1) shearing simulations in the frame of the discrete element method, (2) experimental lab tests using medium to large triaxial devices, and (3) a large in situ direct shear test. We cover a wide range of from 4 to 45. The results show that changes in grading through the scalping technique do not affect the critical shear strength for 12, which is higher than some widely applied international standards requirements.

Keywords: shear strength, waste rock, discrete element method simulations, laboratory triaxial tests, in situ testing

References:
ASTM International 2011, Standard Test Method for Direct Shear Test of Soils Under Consolidated Drained Conditions (ASTM D3080), ASTM International, West Conshohocken.
ASTM International 2020, Standard Test Method for Consolidated Drained Triaxial Compression Test for Soils (ASTM D7181), ASTM International, West Conshohocken.
Bard, E, Anabalón, ME & Campaña, J 2012, ‘Chapter 4’, Waste Rock Behavior at High Pressures, John Wiley & Sons, Hoboken, pp. 83–112.
Barton, N & Kjærnsli, B 1981, ‘Shear strength of rockfill’, Journal of the Geotechnical Engineering, vol. 107, no. 7, pp. 873–891.
British Standard Institution 1990, Methods of test for soils for civil engineering purposes. shear strength tests; part 7 (BS 1377), British Standard Institution.
Cantor, D, Azéma, E, Sornay, P & Radjai, F 2018, ‘Rheology and structure of polydisperse three-dimensional packings of spheres’, Physical Review, E 98, 052910.
Cantor, D & Ovalle, C 2023, ‘Sample size effects on the critical state shear strength of granular materials with varied gradation and the role of column-like local structures’, Géotechnique, in press.
Carrasco, S, Cantor, D & Ovalle, C 2022, ‘Effects of particle size‚Äźshape correlations on steady shear strength of granular materials: The case of particle elongation’, International Journal for Numerical and Analytical Methods in Geomechanics, vol 46, no. 5, pp. 979–1000.
Carrasco, S, Cantor, D, Quiroz, P & Ovalle, C 2023, ‘Shear strength of angular granular materials with size and shape polydispersity’, Open Geomechanics, in press.
Cerato, A & Lutenegger, A 2006, ‘Specimen size and scale effects of direct shear box tests of sands’, Geotechnical Testing Journal, vol. 29.
Deiminiat, A, Li L & Zeng, F 2022, ‘Experimental study on the minimum required specimen width to maximum particle size ratio in direct shear tests’, CivilEng, vol. 3, no. 1, pp. 66–84.
Dubois, F & Jean, M 2022, LMGC90 Wiki Page, , viewed 19 May 2023.
GDR-Midi 2004, ‘On dense granular flows’, European Physical Journal, E 14, pp. 341–365.
Hazzar, L, Nuth, M & Chekired, M 2020, ‘DEM simulation of drained triaxial tests for glass-beads’, Powder Technology, vol. 364, pp. 123–134.
Indraratna, B, Wijewardena, L & Balasubramaniam, A 1993, ‘Large scale triaxial testing of greywacke rockfill’, Géotechnique, vol. 43, no. 1, pp. 539–543.
Jean, M 1999, ‘The non-smooth contact dynamics method’, Computer Methods in Applied Mechanics and Engineering, vol. 177, no. 3-4, pp. 235–257.
Japanese Geotechnical Society 2015a, Preparation of Soil Specimens for Triaxial Tests (JGS 0525), Japanese Geotechnical Society.
Japanese Geotechnical Society 2015b, Preparation of Specimens of Coarse Granular Materials for Triaxial Tests (JGS 0530), Japanese Geotechnical Society.
Japanese Geotechnical Society 2015c, Method for Consolidated Constant Pressure Direct Box Shear Test on Soils (JGS 0561), Japanese Geotechnical Society.
Leps, TM 1970, ‘Review of shearing strength of rockfill’, Journal of the Soil Mechanics and Foundations Division, div. 96, no. 4, pp. 1159–1170.
Li, G, Ovalle, C, Dano, C & Hicher, P-Y 2013, ‘Influence of grain size distribution on critical state of granular materials’, Springer Series in Geomechanics and Geoengineering, pp. 207–210.
Linero, S, Bradfield, L, Fityus, S, Simmons, J & Lizcano, A 2020, ‘Design of a 720-mm square direct shear box and investigation of the impact of boundary conditions on large-scale measured strength’, Geotechnical Testing Journal, vol. 43, 20190344.
Linero, S, Palma, C & Apablaza, R 2007, ‘Geotechnical characterisation of waste material in very high dumps with large scale triaxial testing’, 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. 59–75,
/ACG_repo/708_2
Liu, Y-J, Li, G, Yin, Z-Y, Dano, C, Hicher, P-Y, Xia, X-H & Wang, J-H 2014, ‘Influence of grading on the undrained behavior of granular materials’, Comptes Rendus Mécanique, vol. 342, no. 2, pp. 85–95.
Marachi, N 1969, Strength and Deformation Characteristics of Rockfill Materials, PhD thesis, University of California, Berkeley.
Marsal, RJ 1967, ‘Large scale testing of rockfill materials’, Journal of the Soil Mechanics and Foundations, div. 93, no. 2, pp. 27–43.
Matsuoka, H, Liu, S, Sun, D & Nishikata, U 2001, ‘Development of a new in situ direct shear test’, Geotechnical Testing Journal, vol. 24, pp. 92–102.
McLemore, VT, Fakhimi, A, van Zyl, D, Ayakwah, GF, Anim, K, Boakye, K, Ennin, F, … Viterbo, VC 2009, Literature Review of Other Rock Piles: Characterization, Weathering, and Stability, Open-file Report OF-517, New Mexico Bureau of Geology and Mineral Resources.
Muir Wood, D & Maeda, K 2008, ‘Changing grading of soil: effect on critical states’, Acta Geotechnica, vol. 3, no. 1, pp. 3–14.
Ovalle, C & Dano, C 2020, ‘Effects of particle size-strength and size-shape correlations on parallel grading scaling’, Géotechnique Letters, vol. 10, no. 2, pp. 191–197.
Ovalle, C, Frossard, E, Dano, C, Hu, W, Maiolino, S & Hicher, P-Y 2014, ‘The effect of size on the strength of coarse rock aggregates and large rockfill samples through experimental data’, Acta Mechanica, vol. 225, pp. 2199–2216.
Ovalle, C, Linero, S, Dano, C, Bard, E, Hicher, P-Y & Osses, R 2020, ‘Data compilation from large drained compression triaxial tests on coarse crushable rockfill materials’, Journal of Geotechnical and Geoenvironmental Engineering, vol. 146, no. 9, 06020013.
Polania, O, Cabrera, M, Renouf, M, Azéma, E & Estrada, N 2023, ‘Grain size distribution does not affect the residual shear strength of granular materials: an experimental proof’, Physical Review E, vol. 107, L052901.
Renouf, M, Dubois, F & Alart, P 2004, ‘A parallel version of the non-smooth contact dynamics algorithm applied to the simulation of granular media’, Journal of Computational and Applied Mathematics, vol. 168, no. 1, pp. 375–382.
Valenzuela, L, Bard, E, Campana, J & Anabalon, M 2008, ‘High waste rock dumps - challenges and developments’, in A Fourie (ed.), Rock Dumps, Australian Centre for Geomechanics, Perth.
Voivret, C, Radjai, F, Delenne, J-Y & El Youssoufi, MS 2009, ‘Multiscale force networks in highly polydisperse granular media’, Physical Review Letters, vol. 102, 178001.
Wu, P-K, Matsushima, K & Tatsuoka, F 2008, ‘Effects of specimen size and some other factors on the strength and deformation of granular soil in direct shear tests’, Geotechnical Testing Journal, vol. 31, no. 1, 100773.
Yang, J & Luo, X 2018, ‘The critical state friction angle of granular materials: does it depend on grading?’, Acta Geotechnica, vol. 13.
Zheng, J & Hryciw, RD 2016, ‘Roundness and sphericity of soil particles in assemblies by computational geometry’, Journal of Computing in Civil Engineering, vol. 30, 04016021.




© 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 repository-acg@uwa.edu.au