Quantitative evaluation of stope damage induced by seismic waves
Abstract
In the present study, a methodology to evaluate damage around underground opening due to seismic waves arising from mining-induced fault-slip is proposed. First, expressions for an associated flow rule with a failure criterion developed for biaxial stress conditions are derived, which are newly implemented into FLAC3D code. With the code, stope extraction is simulated, using a 3D mine-wide model encompassing a fault running parallel to a steeply dipping orebody. The failure criterion for biaxial stress conditions is applied to only the rockmass in the vicinity of stopes within the hanging wall. After extracting stopes in the orebody, mining-induced fault-slip is simulated in dynamic conditions, considering its trigger mechanism, i.e., stress drop caused by instantaneous shearing of fault surface asperities, using Barton’s shear strength model. Damage to the rockmass caused by seismic waves is then evaluated with the increase in plastic strain. The proposed methodology takes into account the mechanism of mining-induced fault-slip, propagation of seismic waves, biaxial stress conditions on the surface of openings, and plastic strain as damage criterion.References
Barton, N. (1973). Review of a new shear-strength criterion for rock joints Engineering Geology, Volume 7, pp. 287-332
Barton, N., & Choubey, V. (1977). The shear strength of rock joints in theory and practice. Rock Mechanics, Volume 10, pp. 1-54
Bieniawski, Z. T. (1989). Engineering rock mass classifications. New York: Wiley.
Diederichs, M.S. (2007). The 2003 Canadian Geotechnical Colloquium: Mechanistic interpretation and practical application of damage and spalling prediction criteria for deep tunnelling. Canadian Geotechnial Journal, Volume 44, pp. 1082-1116.
Henning, J. (1998). Ground control strategies at the bousquet 2 mine. (Master), McGill University, Montreal, QC, Canada.
Hoek, E. (2007). Practical rock engineering.
Hoek, E., & Brown, E.T. (1997). Practical estimates of rock mass strength. International Journal of Rock Mechanics and Mining Science, Volume 34, No. 8, pp. 1165-1186.
Hofmann, G.F., & Scheepers, L.J. (2011). Simulating fault slip areas of mining induced seismic tremors using static boundary element numerical modelling. Mining Technology, Volume 120, No. 1, pp. 53-64.
Itasca. (2009). FLAC3D - fast Lagrangian analysis of continua (Version 4.0). U.S.A.: Itasca Consulting Group Inc.
Malek, F., Suorineni, F.T., & Vasak, P. (2009). Geomechanics Strategies for Rockburst Management at Vale Inco Creighton Mine. Paper presented at the ROCKENG09, Toronto.
Mitri, H.S., Edrissi, R., & Henning, J. (1994). Finite element modelling of cable-bolted stopes in hardrock ground mines. Paper presented at the SME Annual Meeting, Albuquerque, New Mexico.
Sainoki, A., & Mitri, H.S. (2014a). Dynamic modelling of fault slip with Barton's shear strength model. International Journal of Rock Mechanics and Mining Science, Volume 67, pp. 155-163
Sainoki, A., & Mitri, H. (2014b). Evaluation of fault-slip potential due to shearing of fault asperities. Canadian Geotechnial Journal, Volume 52, No. 10, pp. 1417-1425.
Tesarik, D.R., Seymour, J.B., & Yanske, T.R. (2003). Post-failure behaviour of two mine pillars confined with backfill. International Journal of Rock Mechanics and Mining Science, Volume 40, No. 2, pp. 221.
Traina, L.A. (1983). Experimental stress-strain behaviour of a low strength concrete under multiaxial states of stress. Kirtland Air Force Base, NM: Air Force Weapons Laboratory.
Wang, X., & Cai, M. (2015). Influence of wavelength-to-excavation span ratio on ground motion around deep underground excavation. Tunnelling and Underground Space Technology, Volume 49, pp. 438-453.
Yun, X., Mitri, H.S., Yang, X., & Wang, Y. (2010). Experimental investigation into biaxial compressive strength of granite. International Journal of Rock Mechanics and Mining Science, Volume 47, pp. 334-341.
Zhang, Y., & Mitri, H. (2008). Elastoplastic stability analysis of mine haulage drift in the vicinity of mined stopes. International Journal of Rock Mechanics and Mining Science, Volume 45, pp. 574-593.
Zhu, W.C., Wei, C.H., Li, S., Wei, J., & Zhang, M.S. (2013). Numerical modeling on destress blasting in coal seam for enhancing gas drainage. International Journal of Rock Mechanics and Mining Science, Volume 59, pp. 179-190.
