Document Type : Original Research Paper

Authors

1 Department of Mining Engineering, Higher Education Complex of Zarand, Zarand, Iran

2 School of Mining Engineering, College of Engineering, University of Tehran, Tehran, Iran

3 Shahid Bahonar University of Kerman, Kerman, Iran

4 Mining and Geology Researches Department, Golgohar Mining and Industrial Company, Sirjan, Iran

Abstract

Estimation of the in-situ block size is known as a key parameter in the characterization of the mechanical properties of rock masses. As the in-situ block size cannot be measured directly, several simplified methods have been developed, where the intrinsic variability of the geometrical features of discontinuities are commonly neglected. This work aims to estimate the in-situ block size distribution (IBSD) using the combined photogrammetry and discrete fracture network (DFN) approaches. To this end, four blasting benches in the Golgohar iron mine No. 1, Sirjan, Iran, are considered as the case studies of this research work. The slope faces are surveyed using the photogrammetry method. Then 3D images are prepared from the generated digital terrain models, and the geometrical characteristics of discontinuities are surveyed. The measured geometrical parameters are statistically analysed, and the joint intensity, the statistical distribution of the orientation, and the fracture trace length are determined. The DFN models are generated, and IBSD for each slope face is determined using the multi-dimensional spacing method. In order to evaluate the validity of the generated DFN models, the geological strength index (GSI) as well as the stereographic distribution of discontinuities in the DFN models are compared against the field measurements. A good agreement has been found between the results of the DFN models and the filed measurements. The results of this work show that the combined photogrammetry and DFN techniques provide a robust, safe, and time-efficient methodology for the estimation of IBSD. 

Keywords

[1]. Battulwar, R., Zare-Naghadehi, M., Emami, E. and Sattarvand, J. (2021). A state-of-the-art review of automated extraction of rock mass discontinuity characteristics using three-dimensional surface models. Journal of Rock Mechanics and Geotechnical Engineering. 13 (4): 920-936.
[2]. Bonilla-Sierra, V., Elmouttie, M., Donzé, F.-V., and Scholtès, L. (2017). Composite wedge failure using photogrammetric measurements and DFN-DEM modelling. Journal of Rock Mechanics and Geotechnical Engineering. 9 (1): 41-53.
[3]. Bahaaddini, M. and Hosseinpour Moghadam, E. (2019). Evaluation of empirical approaches in estimating the deformation modulus of rock masses. Bulletin of Engineering Geology and Environment. 78 (5): 3493-3507.
[4]. Da Gama, C.D. (1977). Computer model for block size analysis of jointed rock masses. Proc, 15th APCOM Symposium. Brisbane, Australia, 305-315.
[5]. Stewart, D.R. (1986). A review of techniques for predicting the natural fragmentation characteristics of block caving orebodies. Proc, Application of Rock Characterisation Techniques in Mine Design. Littleton, USA, SME, 181-189.
[6]. Xu, J. and Cojean, R. (1990). Three dimensional simulation of natural rock granulometry (in French). Proc, 6th International Congress International Association of Engineering Geology, Amsterdam, Rotterdam, A A Balkema, 797-802.
[7]. Kleine, T.H. and Villaescusa, E. (1990). A rock joint model to estimate the in-situ block size distribution in natural joint rock. Proc, 22nd APCOM Symposium, Berlin, Germany, 693-704.
[8]. Wang, H. (1992). Predictions of in-situ and blastpile block size distributions of rock masses, with special reference to coastal requirements, PhD Thesis, Queen Mary and Westfield College, London University, London, UK.
[9]. Wang, H., Latham, J.-P., and Poole, A.B. (1990). In-situ block size assessment from discontinuity spacing data. Proc, 6th IAGE Congress, Rotterdam, Balkema, 117-127.
[10]. Wang, H., Latham, J.-P., and Poole, A.B. (1991). Predictions of block size distribution for quarrying. Quarterly Journal of Engineering Geology and Hydrogeology. 24 (1): 91-99.
[11]. Goodman, R.E. and Shi, G. (1985) Block theory and its application to rock engineering. New Jersey, Prentice-Hall.
[12]. Dershowitz, W.S. and Herda, H.H. (1992). Interpretation of fracture spacing and intensity. Proc, The 33rd US Symposium on Rock Mechanics (USRMS). Santa Fe, New Mexico, ARMA-92-0757.
[13]. Maerz, N.H. and Germain, P. (1996). Block size determination around underground openings using simulations. Proc, FRAGBLAST 5 workshop on measurement of blast fragmentation. Montreal, Quebec, Canada, 215–223.
[14]. Lu, P. and Latham, J.P. (1999). Developments in the assessment of in-situ block size distributions of rock masses. Rock Mechanics and Rock Engineering. 32 (1): 29-49.
[15]. Palmström, A. (2001). Measurement and characterization of rock mass jointing. Proc, In-situ characterization of rocks, A. A. Balkema.
[16]. Cai, M., Kaiser, P.K., Uno, H., Tasaka, Y., and Minami, M. (2004). Estimation of rock mass deformation modulus and strength of jointed hard rock masses using the GSI system. International Journal of Rock Mechanics and Mining Sciences, 41 (1), 3-19.
[17]. Jern, M. (2004). Determination of the in situ block size distribution in fractured rock, an approach for comparing in-situ rock with rock sieve analysis. Rock Mechanics and Rock Engineering. 37 (5): 391-401.
[18]. Latham, J.-P., Van Meulen, J., and Dupray, S. (2006). Prediction of in-situ block size distributions with reference to armourstone for breakwaters. Engineering Geology. 86 (1): 18-36.
[19]. Kim, B.H., Cai, M., Kaiser, P.K., and Yang, H.S. (2006). Estimation of block sizes for rock masses with non-persistent joints. Rock Mechanics and Rock Engineering. 40 (2): 169-192.
[20]. Elmouttie, M.K. and Poropat, G.V. (2012). A method to estimate in situ block size distribution. Rock Mechanics and Rock Engineering. 45 (3): 401-407.
[21]. Elmo, D., Rogers, S., Stead, D., and Eberhardt, E. (2014). Discrete Fracture Network approach to characterise rock mass fragmentation and implications for geomechanical upscaling. Mining Technology. 123 (3): 149-161.
[22]. Miyoshi, T., Elmo, D., and Rogers, S. (2018). Influence of data analysis when exploiting DFN model representation in the application of rock mass classification systems. Journal of Rock Mechanics and Geotechnical Engineering. 10 (6): 1046-1062.
[23]. Stavropoulou, M. and Xiroudakis, G. (2020). Fracture frequency and block volume distribution in rock masses. Rock Mechanics and Rock Engineering. 53 (10): 4673-4689.
[24]. Poropat, G.V. (2006). Remote 3D mapping of rock mass structure. Proc,  The 41st US Rock Mechanics Symposium. Alexandria, VA.
[25]. Zhang, D., Zhang, Y., Cheng, T., Meng, Y., Fang, K., Garg, A. et al. (2017). Measurement of displacement for open-pit to underground mining transition using digital photogrammetry. Measurement. 109: 187-199.
[26]. Bar, N., Kostadinovski, M., Tucker, M., Byng, G., Rachmatullah, R., Maldonado, A. et al. (2020). Rapid and robust slope failure appraisal using aerial photogrammetry and 3D slope stability models. International Journal of Mining Science and Technology. 30 (5): 651-658.
[27]. Firpo, G., Salvini, R., Francioni, M., and Ranjith, P.G. (2011). Use of digital terrestrial photogrammetry in rocky slope stability analysis by distinct elements numerical methods. International Journal of Rock Mechanics and Mining Sciences. 48 (7): 1045-1054.
[28]. Sturzenegger, M. and Stead, D. (2009). Close-range terrestrial digital photogrammetry and terrestrial laser scanning for discontinuity characterization on rock cuts. Engineering Geology, 106 (3–4), 163-182.
[29]. Tannant, D.D. (2015). Review of photogrammetry-based techniques for characterization and hazard assessment of rock faces International Journal of Geohazards and Environment. 1 (2): 76-87.
[30]. Emamzadeh, A.M., Bahaaddini, M., Saeedi, G., and Mohammadi, H.R. (2019). Determination of the block volume and the geological strength index (GSI) using photogrammetry approach in Golgohor iron mine of Sirjan. Iranian Journal of Mining Engineering. 14 (42): 47-58.
[31]. Haneberg, W. (2008). Using close range terrestrial digital photogrammetry for 3-D rock slope modeling and discontinuity mapping in the United States. Bulletin of Engineering Geology and Environment. 67 (4): 457-469.
[32]. Gaich, A. and Pötsch, M. (2016). Gaich 2016 3D images for digital tunnel face documentation at TBM headings–Application at Koralmtunnel lot KAT2 Geomechanics and Tunnelling. 9 (3): 210-221.
[33]. Slaker, B.A. and Mohamed, K.M. (2017). A practical application of photogrammetry to perform rib characterization measurements in an underground coal mine using a DSLR camera. International Journal of Mining Science and Technology. 27 (1): 83-90.
[34]. Benton, D.J., Iverson, S.R., Martin, L.A., Johnson, J.C., and Raffaldi, M.J. (2016). Volumetric measurement of rock movement using photogrammetry. International Journal of Mining Science and Technology. 26 (1): 123-130.
[35]. Slaker, B., Westman, E., Ellenberger, J., and Murphy, M. (2016). Determination of volumetric changes at an underground stone mine: a photogrammetry case study. International Journal of Mining Science and Technology. 26 (1): 149-154.
[36]. Bahaaddini, M. (2014). Numerical study of the mechanical behaviour of rock joints and non-persistent jointed rock masses, PhD Thesis, UNSW Australia, Sydney, Australia.
[37]. Bahaaddini, M., Hagan, P.C., Mitra, R., and Hebblewhite, B.K. (2014). Scale effect on the shear behaviour of rock joints based on a numerical study. Engineering Geology, 181, 212-223.
[38]. Bahaaddini, M., Sharrock, G., Hebblewhite, B., and Mitra, R. (2012). Direct shear tests to model the shear behaviour of rock joints by PFC2D. 46th US Rock Mechanics/Geomechanics Symposium. Chicago, IL, USA.
[39]. Khosravi, M.H., Pipatpongsa, T., Takahashi, A., and Takemura, J. (2011). Arch action over an excavated pit on a stable scarp investigated by physical model tests. Soils and Foundations. 51 (4): 723-735.
[40]. Khosravi, M., Tang, L., Pipatpongsa, T., Takemura, J., and Doncommul, P. (2012). Performance of counterweight balance on stability of undercut slope evaluated by physical modeling. International Journal of Geotechnical Engineering. 6 (2): 193-205.
[41]. Amoushahi, S., Grenon, M., Locat, J., and Turmel, D. (2018). Deterministic and probabilistic stability analysis of a mining rock slope in the vicinity of a major public road—case study of the LAB Chrysotile mine in Canada. Canadian Geotechnical Journal. 55 (10): 1391-1404.
[42]. Elmo, D., Stead, D. and Rogers, S. (2015). Guidelines for the quantitative description of discontinuities for use in discrete fracture network modelling. Proc, 13th ISRM International Congress of Rock Mechanics.
[43]. Hadjigeorgiou, J. (2012). Where does the data come from? Mining Technology. 121 (4): 236-247.
[44]. Mohammadi, H.R., Mansouri, H., Bahaaddini, M., and Jalalifar, H. (2017). Investigation into the effect of fault properties on wave transmission. International Journal for Numerical and Analytical Methods in Geomechanics. 41 (17): 1741-1757.
[45]. ADAM Technology. (2010) 3DM analyst mine mapping suite manual. Perth, Australia.
[46]. Golder Associates Ltd. (2018) FracMan® User’s Manual Release 7.7.