A STUDY ON NUMERICAL COUPLING BETWEEN MECHANICAL AND HYDRAULIC BEHAVIORS IN A GRANITE ROCK MASS SUBJECT TO HIGH-PRESSURE INJECTION

  • Jeong, Woo-Chang (Research Center for Disaster Prevention and Safety Management, Hong-Ik University) ;
  • Jai-Woo (Centre d´Informatique Geologique, Ecole Nationale Superieure des Mines de Paris) ;
  • Song, Jai-Woo (Department of Civil Engineering, Hong-Ik University)
  • Published : 2001.04.01

Abstract

An injection experiment was carried ut to investigate the pressure domain within which hydromechanical coupling influences considerably the hydrologic behavior of a granite rock mass. The resulting database is used for testing a numerical model dedicated to the analysis of such hydromechanical interactions. These measurements were performed in an open hole section, isolated from shallower zones by a packer set at a depth of 275 m and extending down to 840 m. They consisted in a series of flow meter injection tests, at increasing injection rates. Field results showed that conductive fractures from a dynamic and interdependent network, that individual fracture zones could not be adequately modeled as independent systems, that new fluid intakes zones appeared when pore pressure exceeded the minimum principal stress magnitude in that well, and that pore pressures much larger than this minimum stress could be further supported by the circulated fractures. These characteristics give rise to the question of the influence of the morphology of the natural fracture network in a rock mass under anisotropic stress conditions on the effects of hydromechanical couplings.

Keywords

References

  1. Abdallah, G., Thoraval, A., Sfeir, A., and Piguet, J.P. (1995). 'Thermal convection of fluid in fractured media.' Int. J. Rock. Mech. Sci & Abstr., Vol. 32, No. 5,pp. 481-490 https://doi.org/10.1016/0148-9062(95)00037-H
  2. Bandis, S. C., Lumsden, A. C., and Barton, N. R. (1983). 'Fundamentals of rock joint deformation.' Int. J. Rock Mech. Sci. & Abstr., Vol. 20, No. 6, pp. 249-268 https://doi.org/10.1016/0148-9062(83)90595-8
  3. Brown, S. R. and Scholz, C. H. (1985). 'Closure of random clastic surfaces in contact.' Journal of Geoph. Research, 90(B7), pp. 5531-5545
  4. Bruel, D. and Cornet, F. H. (1995). 'Forced fluid flow trough fractured reservoir s modelling.' In Fractured and Jointed rock Masses, Edited by Myer, Cook, Goodman and Tsang, pp. 503-510
  5. Bruel, D. (1999). 'Modelling hydraulic jacking tests on a pre-exisiting fracture system.' Proceedings Ninth International Congress on Rock Mechanics, Balkema, Rotterdam, pp. 863-868
  6. Capasso, G., Scavia, C., Gentier, S., and Pellegrino, A. (1999). 'The influence of normal load on the hydraulic behaviour of rock fractures.' Proceedings Ninth International Congress on Rock Mechanics, Edited by Vouille and Berest, Rotterdam, Balkema, pp. 863-868
  7. Cornet, F.H., Bidaux, P., Binon, M., Blum, P. A., Couturie, J. P., Jolivet, J., Mosnier, J., Martel, L., Saleh, B., and Talebi, S. (1985). Etude in situ de la percolation force$\'{e}$ d'eau en milieu fissure. Fesultate du programme mayet de Montagne pour la periode 1983-1985. Rapport AFME-INSU-PIRSEM, Institut de Physique du Globe de Paris
  8. Cornet, F. H. and Scotti, O. (1993). 'Analysis of induced scismicity for fault zone identification.' Int. J. Rock Mech. Min. Sci & Abstr., Vol. 30, No. 7, pp. 789-795 https://doi.org/10.1016/0148-9062(93)90024-8
  9. Cornet, F. H. and Morin, R. H. (1997). 'Evaluation of hydromechanical coupling in a granite rock mass from a high-volume, high-pressure injection experiment: le Mayet de Montagne, France'. Int. J. Rock Mech & Min. Sci. 34:3-4, paper No. 207
  10. Cundall, P. A. and Hart, R. D. (1985). Development of generalized 2D and 3D Distinct Element Programs for modelling jointed rocks. Misc. Paper SL-85-1, U.S. Army Corps of Engineers
  11. Gentier, S. (1986). Morphologie et comportement hydromechanique d'une fracture naturelle dans un granite sous contrainte normale : etude experimental et technique, These de Doctorat, Univerite d'Oreans, 1986
  12. Jeong, W. C. (2000). Modelisation de l'influence d'une zone de faille sur l'hydrogeologie d'un milieu fracture. These de l'Ecole Ntionale superieure des Mines de Paris, p. 278
  13. Pyrak-Nolte, L. (1992). 'Interrelationships between the hydraulic and seismic prpperties of fractures.' Proceedinds. of ISRM International Conference on fractured and jointed rock masses, Lake Tahoe, California, USA
  14. Raven, K. G. and Gale. J. E. (1985). 'Water flow in natural rock fracture as a function of stress and sample size.' Int. J. Rock Min. Sci & Abstr., Vol. 22, pp. 251-261 https://doi.org/10.1016/0148-9062(85)92952-3
  15. Rutqvist, J. (1995). 'Determination of hydraulic normal stiffness of fractures in hard rock from well testing.' Int. J. Rock Min. Sci & Abstr., Vol. 32, No. 5, pp. 513-523 https://doi.org/10.1016/0148-9062(95)00039-J
  16. Sinha, K. P. (1979). Displacement discontinuity technique for analysing stresses and displacements due to mining in esam deposit. Ph.D. dissertation, University of Minnesota
  17. Stephansson, O., Jing, L. and Tsang, C. F. (editors) (1996). 'Coupled Thermo-Hydromechanical processes of fractured media.' Developments in geothechnical engineering(79), Elsevier, The Nederlands
  18. Unger, A. J. A. and Mase, C. W. (1993). 'Numerical study of the hydromechanical behaviour of two rough fracture surfaces in contact.' Water Resources Research, Vol.29, No.7, pp. 2101-2114 https://doi.org/10.1029/93WR00516
  19. Yin, J. M. and Cornet, F. H. (1994). 'Integrated stress determination by joint inversion of hydraulic tests and focal mechanism.' Geoph. Res. Letters, Vol. 21, No. 24, pp. 2645-2648 https://doi.org/10.1029/94GL02584
  20. Zimmerman, R. W. and Bodvarsson, G.S. (1996). 'Hydraulic conductivity of rock fractures.' Transport in porous media, No. 23, pp. 1-30