Normal Deformation and Formation of Contacts in Rough Rock Fractures and Their Influence on Fluid Flow
Publication: International Journal of Geomechanics
Volume 17, Issue 1
Abstract
Rock fracture flow was initially modeled according to the parallel plate model, which does not consider the undulating nature of fracture surfaces. The conventional parallel plate model or cubic formula was later modified to obtain precise predictions by considering the joint roughness coefficient (JRC) of the fracture walls. However, the real flow characteristics through a relatively long rough rock joint can still be modeled accurately via a two-dimensional analysis, which enables the spatial irregularity of rock fracture apertures to be considered with the fracture contacts, which act as obstacles to the flow. In this study, a new two-dimensional flow model for deformable fracture walls to predict the volumetric flow changes that result from effective normal stress fluctuations is proposed. This model was solved using the finite-volume method via a new program developed by the authors. It captures the existing contacts and newly formed contacts that occur while fracture aperture deformations take place and treats them as local boundaries. The model flow-rate predictions were compared with the simulated real rock fracture flow carried out on a high-pressure two-phase triaxial apparatus (HPTPTA) designed and built at the Univ. of Wollongong (Wollongong City, Australia). The model predictions and experiment results of volumetric flow rates were in good agreement, which verifies the accuracy of incorporating a more realistic contact treatment process between the upper and lower asperities during joint closure. The numerical simulations illustrate flow paths within the rock fracture in a more realistic manner without having to consider the entire fracture surface to be permeable.
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Acknowledgments
The authors acknowledge the support given by Dr. Winton Gale, SCT Pty, the technical staff of the Univ. of Wollongong for the laboratory experiments, and the Australian Research Council (ARC) and Endeavour postgraduate award program for funding this research project. The authors gratefully acknowledge that some of the insightful and constructive comments made by the reviewers also contributed to the enhanced quality of this report.
References
Bandis, S., Lumsden, A. C., and Barton, N. R. (1983). “Fundamentals of rock joint deformation.” Rock Mech. Min. Sci. Geomech. Abstr., 20(6), 249–268.
Bear, J., Tsang, C. F., and de Marsily, G. (1993). Flow and contaminant transport in fractured rock, Academic Press, Cambridge, MA.
Brown, S. R. (1987). “Fluid flow through rock joints: The effect of surface roughness.” Geophys. Res., 92(B2).
Gale, J. E. (1977). A numerical field and laboratory study of flow in rocks with deformable fractures, Scientific Series, No. 72, Canada Centre for Inland Waters, Burlington, ON, Canada.
Gangi, A. F. (1978). “Variation of whole and fractured porous rock permeability with confining pressure.” Int. J. Rock Mech. Min. Sci. Geomech. Abstr., 15(5), 249–257.
Goodman, R. E. (1974). “The mechanical properties of joints.” Proc., 3rd Congress of ISRM, National Academy of Sciences, Washington, DC.
Indraratna, B., and Ranjith, P. G. (2001). “Laboratory measurement of two-phase flow parameters on high pressure triaxial testing.” J. Geotech. Geoenviron. Eng., 530–542.
Indraratna, B., Kumara, C., Zhu, S., and Sloan, S. (2014). “Mathematical modeling and experimental verification of fluid flow through deformable rough rock joints.” Int. J. Geomech., 04014065.
Indraratna, B., Price, J., Ranjith, P., and Gale, W. (2002). “Some aspects of unsaturated flow in jointed rock.” Int. J. Rock Mech. Min. Sci., 39(5), 555–568.
Indraratna, B., Ranjith, P., Price, J., and Gale, W. (2003). “Two-phase (air and water) flow through rock joints: Analytical and experimental study.” Geotech. Geoenviron. Eng., 918–928.
Kishida, K., Sawada, A., Yasuhara, H., and Hosoda, T. (2013). “Estimation of fracture flow considering the inhomogeneous structure of single rock fractures.” Soils Found., 53(1), 105–116.
Koyama, T. (2007). “Stress, flow and particle transport in rock fractures.” Ph.D. thesis, Royal Institute of Technology, Stockholm, Sweden.
Koyama, T., Neretnieks, I., and Jing, L. (2008). “A numerical study on differences in using Navier–Stokes and Reynolds equations for modeling the fluid flow and particle transport in single rock fractures with shear.” Int. J. Rock Mech. Min. Sci., 45(7), 1082–1101.
Kulhawy, F. H. (1975). “Stress deformation properties of rock and rock discontinuities.” Eng. Geol., 9(4), 327–350.
Louis, C. A. (1969). “A study of groundwater flow in jointed rock and its influence of the stability of rock masses.” Rock Mechanics Research Rep. 10, Imperial College, London.
MATLAB [Computer software]. MathWorks, Natick, MA.
Patankar, S. V., and Spalding, D. B. (1972). “A calculation procedure for heat, mass and momentum transfer in three-dimensional parabolic flows.” Int. J. Heat Mass Transfer, 15(10), 1787–1806.
Snow, D. T. (1968). “Rock fracture spacings, openings and porosities.” Soil Mech. Found. Div., 94(1), 73–91.
Tsang, Y. W. (1984). “The effect of tortuosity on fluid flow through a single fracture.” Water Resour. Res., 20(9), 1209–1215.
Witherspoon, P. A., Wang, J. S. Y., Iwai, K., and Gale, J. E. (1980). “Validity of cubic law for fluid flow in a deformable rock fracture.” Water Resour. Res., 16(6), 1016–1024.
Yeo, W. (2001). “Effect of contact obstacles on fluid flow in rock fractures.” Geosci. J., 5(2), 139–143.
Zimmerman, R. W., and Bodvarsson, G. S. (1996). “Hydraulic conductivity of rock fractures.” Transp. Porous Media, 23(1), 1–30.
Zimmerman, R. W., and Yeo, I.-W. (2013). “Fluid flow in rock fractures: From the Navier–Stokes Equations to the Cubic Law.” Dynamics of fluids in fractured rock, American Geophysical Union, Washington, DC, 213–224.
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Published In
International Journal of Geomechanics
Volume 17 • Issue 1 • January 2017
Copyright
© 2016 American Society of Civil Engineers.
History
Received: Aug 27, 2014
Accepted: Dec 1, 2015
Published online: Mar 9, 2016
Discussion open until: Aug 9, 2016
Published in print: Jan 1, 2017
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