Abstract
Comprehensive tests were conducted on a longwall face in China to study mining-induced strata movement and fractures. The first and periodic weightings of the main roof were both captured by microseismic (MS) monitoring and support resistance recording and were 64 and 20 m, respectively. Based on the fracture detection through hydrological observations in a borehole, the roof is clearly divided into three zones: water-conductive zone, horizontal fracture, and continuous zone. Following the field investigation, an innovative finite-difference method (FDM) and distinct-element method (DEM) coupled numerical simulation method was proposed, which features simulating the progressive failure of the rock mass from intact to blocky. The numerical study shows that the proposed coupled method can give reasonable explanations for all in situ tests and handle the progressive caving of the rock layers, as well as the accompanying MS activities and response of the hydraulic supports. The proposed coupled method has advantages over a continuum or discrete method in coal mining simulation. Compared with a continuum method, the coupled method can simulate the deformation and collapse of the overburden strata, whereas the continuum method is only applicable before the first weighting of the rock layer, after which it gives wrong results. In contrast, compared with a discrete method where the blocks are factitiously set before and their sizes are mandatory, the coupled method allows the blocks to form automatically based on the failure state of the rock mass.
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Acknowledgments
The authors gratefully acknowledge the support of the National Basic Research Program of China (973 Program, Grant 2013CB227902), the Natural Science Foundation of China (Grant 51474215), the China Postdoctoral Science Foundation funded project (Grant 2014M561728), and the Natural Science Foundation of Jiangsu Province of China (Grant BK20160249).
References
Alejano, L. R., Ramı´Rez-Oyanguren, P., and Taboada, J. (1999). “FDM predictive methodology for subsidence due to flat and inclined coal seam mining.” Int. J. Rock Mech. Min. Sci., 36((4), 475–491.
Anyaegbunam, A. J. (2015). “Nonlinear power-type failure laws for geomaterials: Synthesis from triaxial data, properties, and applications.” Int. J. Geomech., 04014036-1.
Brady, B., and Brown, E. (1993). Rock mechanics for underground mining, Chapman and Hall, London.
Coulthard, M. A. (1999). “Applications of numerical modelling in underground mining and construction.” Geotech. Geol. Eng., 17(3–4), 373–385.
3DEC [Computer software]. Itasca, Minneapolis.
Deere, D. (1967). “Technical description of rock cores for engineering purposes.” Rock Mech. Rock Eng., 1, 107–116.
Djamaluddin, I., Mitani, Y., and Ikemi, H. (2012). “GIS-based computational method for simulating the components of 3D dynamic ground subsidence during the process of undermining.” Int. J. Geomech., 43–53.
Elmo, D., Stead, D., Eberhardt, E., and Vyazmensky, A. (2013). “Applications of finite/discrete element modeling to rock engineering problems.” Int. J. Geomech., 565–580.
Gao, F., Stead, D., and Coggan, J. (2014). “Evaluation of coal longwall caving characteristics using an innovative UDEC Trigon approach.” Comput. Geotech., 55(55), 448–460.
Gao, F., Stead, D., and Elmo, D. (2016). “Numerical simulation of microstructure of brittle rock using a grain-breakable distinct element grain-based model.” Comput. Geotech., 78, 203–217.
Gui, H., Song, X., and Lin, M. (2017). “Water-inrush mechanism research mining above karst confined aquifer and applications in North China coalmines.” Arabian J. Geosci., 10(7), 180.
Guo, H., Yuan, L., Shen, B., Qu, Q., and Xue, J. (2012). “Mining-induced strata stress changes, fractures and gas flow dynamics in multi-seam longwall mining.” Int. J. Rock Mech. Min. Sci., 54, 129–139.
Hammah, R., and Curran, J. (2009). “It is better to be approximately right than precisely wrong: Why simple models work in mining geomechanics.” International Workshop on Numerical Modeling for Underground Excavation Design, Dept. of Health and Human Services, Washington, DC, 55–61.
Islavath, S. R., Deb, D., and Kumar, H. (2016). “Numerical analysis of a longwall mining cycle and development of a composite longwall index.” Int. J. Rock Mech. Min. Sci., 89, 43–54.
Kay, D., McNabb, K., and Carter, J. (1991). “Numerical modelling of mine subsidence at Angus Place Colliery.” Proc., Symp. Computer Methods and Advances in Geomechanics, Balkema, Leiden, Netherlands, 999–1004.
Kelly, M., Luo, X., and Craig, S. (2002). “Integrating tools for longwall geomechanics assessment.” Int. J. Rock Mech. Min. Sci., 39(5), 661–676.
Li, Y., et al. (2016). “Real-time microseismic monitoring and its characteristic analysis in working face with high-intensity mining.” J. Appl. Geophys., 132, 152–163.
Miao, X. X., Cui, X. M., Wang, J. A., and Xu, J. L. (2011). “The height of fractured water-conducting zone in undermined rock strata.” Eng. Geol., 120(1–4), 32–39.
Palchik, V. (2003). “Formation of fractured zones in overburden due to longwall mining.” Environ. Geol., 44(1), 28–38.
Palchik, V. (2005). “Localization of mining-induced horizontal fractures along rock layer interfaces in overburden: Field measurements and prediction.” Environ. Geol., 48(1), 68–80.
Palmstrøm, A. (1996). “Characterizing rock masses by the RMi for use in practical rock engineering: Part 1: The development of the Rock Mass index (RMi).” Tunnelling Underground Space Technol., 11(2), 175–188.
Peng, S., Ma, W., and Zhong, W. (1992). Surface subsidence engineering, Society for Mining, Metallurgy, and Exploration, Littleton, CO.
Qian, M., and Xu, J. (1998). “Study of the ‘O-shape’ circle distribution characteristics of mining-induced fractures in the overlaying strata.” J. China Coal Soc., 23(5), 466–469.
Shao, J., Zhou, H., and Chau, K. (2005). “Coupling between anisotropic damage and permeability variation in brittle rocks.” Int. J. Numer. Anal. Methods Geomech., 29(12), 1231–1247.
Shen, B., King, A., and Guo, H. (2008). “Displacement, stress and seismicity in roadway roofs during mining-induced failure.” Int. J. Rock Mech. Min. Sci., 45(5), 672–688.
Shen, B., Luo, X., Moodie, A., and McKay, G. (2013). “Monitoring longwall weighting at Austar Mine using microseismic systems and stressmeters.” 13th Coal Operators' Conf., Univ. of Wollongong, NSW, Australia, 50–59.
Sui, W., et al. (2015). “Interactions of overburden failure zones due to multiple-seam mining using longwall caving.” Bull. Eng. Geol. Environ., 74(3), 1019–1035.
Trivedi, A. (2013). “Estimating in situ deformation of rock masses using a hardening parameter and RQD.” Int. J. Geomech., 348–364.
Ulusay, R. (2015). The ISRM suggested methods for rock characterization, testing and monitoring: 2007–2014, Springer, New York.
Verma, A., and Deb, D. (2013). “Numerical analysis of an interaction between hydraulic-powered support and surrounding rock strata.” Int. J. Geomech., 181–192.
Widisinghe, S., and Sivakugan, N. (2014). “Vertical stress isobars for trenches and mine stopes containing granular backfills.” Int. J. Geomech., 313–318.
Yalcin, E., Gurocak, Z., Ghabchi, R., and Zaman, M. (2016). “Numerical analysis for a realistic support design: Case study of the Komurhan Tunnel in eastern Turkey.” Int. J. Geomech., 05015001.
Yang, S., Zhang, J., Chen, Y., and Song, Z. (2016). “Effect of upward angle on the drawing mechanism in longwall top-coal caving mining.” Int. J. Rock Mech. Min. Sci., 85, 92–101.
Zhang, J., Deng, X., Zhao, X., Ju, F., and Li, B. (2017). “Effective control and performance measurement of solid waste backfill in coal mining.” Int. J. Min., Reclam. Environ., 31(2), 91–104.
Zhang, K., Zhang, G., Hou, R., Wu, Y., and Zhou, H. (2015). “Stress evolution in roadway rock bolts during mining in a fully mechanized longwall face, and an evaluation of rock bolt support design.” Rock Mech. Rock Eng., 48(1), 333–344.
Zhang, K., Zhou, H., and Shao, J. (2013). “An experimental investigation and an elastoplastic constitutive model for a porous rock.” Rock Mech. Rock Eng., 46(6), 1499–1511.
Zhang, L. (2010). “Estimating the strength of jointed rock masses.” Rock Mech. Rock Eng., 43(4), 391–402.
Zhang, L., and Einstein, H. H. (2004). “Using RQD to estimate the deformation modulus of rock masses.” Int. J. Rock Mech. Min. Sci., 41(2), 337–341.
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Published In
International Journal of Geomechanics
Volume 18 • Issue 1 • January 2018
Copyright
© 2017 American Society of Civil Engineers.
History
Received: Feb 22, 2017
Accepted: Jul 27, 2017
Published online: Oct 31, 2017
Published in print: Jan 1, 2018
Discussion open until: Mar 31, 2018
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