Evaluation of Geomechanical and Geometrical Parameters’ Effects on Hydro-Mechanical Estimation of Water Inflow into Underground Excavations
In general, mechanical and hydraulic processes are not independent of each other in jointed rock masses. Therefore, the study on hydro-mechanical coupling of geomaterials should be a center of attention in rock mechanics. Rocks in their nature contain discontinuities whose presence extremely influences mechanical and hydraulic characteristics of the medium. Assuming this effect, experimental investigations on intact rock cannot help to identify jointed rock mass behavior. Hence, numerical methods are being used for this purpose. In this paper, water inflow into a tunnel under significant water table has been estimated using hydro-mechanical discrete element method (HM-DEM). Besides, effects of geomechanical and geometrical parameters including constitutive model, friction angle, joint spacing, dip of joint sets, and stress factor on the estimated inflow rate have been studied. Results demonstrate that inflow rates are not identical for different constitutive models. Also, inflow rate reduces with increased spacing and stress factor.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.2021883Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 342
 S. D. Priest, Discontinuity Analysis for Rock Engineering, Chapman and Hall, First Edition, 1995.
 L. Jing, O. Stephansson, Fundamental of Discrete Element Methods for Rock Engineering Theory and Applications, Elsevier, 2007.
 R. W. Zimmerman, G. S. Bodvarsson, “Hydraulic conductivity of fractures,” Transport in Porous Media, vol. 23, pp. 1-30, 1996.
 W. F. Brace, “A note on permeability changes in geologic material due to stress,” Rock Friction and Earthquake Prediction, vol. 6, pp. 627-633, 1978.
 D. T. Snow, “Fracture Deformation and Changes of Permeability and Storage upon Changes of Fluid Pressure,” Quarterly Journal Colorado School of Mines, vol. 63, pp. 201-244, 1968.
 J. B. Walsh, “Effect of pore pressure and confining pressure on fracture permeability,” International Journal of Rock Mechanics & Mining Sciences & Geomechanics Abstract, vol. 18, pp. 429-435, 1981.
 T. Esaki, S. Du, Y. Mitani, K. Ikusada, L. Jing, “Development of a shear-flow test apparatus and determination of coupled properties for a single rock joint,” International Journal of Rock Mechanics, vol. 36, pp. 641– 650, 1999.
 P. A. Witherspoon, J. S. Wang, K. J. Iwai, J. E. Gale, “Validity of cubic law for fluid-flow in a deformable rock fracture,” Water resources research, vol. 16, pp. 1016-1024, 1980.
 R. W. Zimmerman, D. W. Chen, N. G. W. Cook, “The effect of contact area on the permeability of fractures,” Journal of Hydrology, vol. 139, pp. 79-96, 1992.
 L. J. Pyrak-Nolte, J. P. Morris, “Single fractures under normal stress: The relation between fracture specific stiffness and fluid flow,” International Journal of Rock Mechanics, vol. 37, pp. 245-262, 2000.
 R. W. Zimmerman, A. Al-Yarrubi, C. Pain, C. A. Grattoni, “Non-linear regimes of fluid flow in rock fractures”, International Journal of Rock Mechanics & Mining Sciences, vol. 41, pp. 163-169, 2004.
 M. Sharifzadeh, S. Kargar, “Hydraulic and hydro-mechanical analysis of rock mass mass surrounded a tunnel using DEM,” in Proc. 7th Iranian Tunnelling Conference, Tehran, 2007 (in Persian).
 D. M. Mas Ivars, “Water inflow into excavations in fractured rock—a three-dimensional hydro-mechanical numerical study,” International Journal of Rock Mechanics & Mining Sciences, vol. 41, pp. 705-725, 2006.
 H. Lin, C. Lee, “An approach to assessing the hydraulic conductivity disturbance in fractured rocks around the Syueshan tunnel, Taiwan,” Tunnelling and Underground Space Technology, vol. 24, pp. 79-96, 2009.
 Itasca Consulting Group, UDEC 6.0 Software User Manual, 2013.