Characteristics of Block Hydraulic Conductivity of 2-D DFN System According to Block Size and Fracture Geometry

- Journal title : Tunnel and Underground Space
- Volume 25, Issue 5, 2015, pp.450-461
- Publisher : Korean Society for Rock Mechanics
- DOI : 10.7474/TUS.2015.25.5.450

Title & Authors

Characteristics of Block Hydraulic Conductivity of 2-D DFN System According to Block Size and Fracture Geometry

Han, Jisu; Um, Jeong-Gi;

Han, Jisu; Um, Jeong-Gi;

Abstract

Extensive numerical experiments have been carried out to investigate effect of block size and fracture geometry on hydraulic characteristics of fractured rock masses based on connected pipe flow in DFN systems. Using two fracture sets, a total of 72 2-D fracture configurations were generated with different combinations of fracture size distribution and deterministic fracture density. The directional block conductivity including the theoretical block conductivity, principal conductivity tensor and average block conductivity for each generated fracture network system were calculated using the 2-D equivalent pipe network method. There exist significant effects of block size, orientation, density and size of fractures in a fractured rock mass on its hydraulic behavior. We have been further verified that it is more difficult to reach the REV size for the fluid flow network with decreasing intersection angle of two fracture sets, fracture plane density and fracture size distribution.

Keywords

Fractured rock mass;Discrete fracture network;Block hydraulic conductivity;Representative elementary volume;

Language

Korean

Cited by

References

1.

Andersson, J. and B. Dverstorp, 1987, Conditional simulations of fluid flow in three dimensional networks of discrete fractures, Water Resour. Res. 23.10, 1876-1886.

2.

Bang, S., S. Jeon and J. Choe, 2003, Determination of equivalent hydraulic conductivity of rock mass using three-dimensional discontinuity network, J. of Korean Society for Rock Mech., 13, 52-3.

3.

Bear, J., C.F. Tsang and G. de Marsily, 1993, Flow and Contaminant Transport in Fractured Rock, Academic Press, San Diego, 560p.

4.

Cacas, M.C., E. Ledoux, G. de Marsily, B. Tillie, A. Barbreau, E. Durand, B. Feuga and P. Peaudecerf, 1990a, Modeling fracture flow with a stochastic discrete fracture network: calibration and validation: 1. The flow model, Water Resour. Res. 26.3, 479-489.

5.

Cacas, M.C., E. Ledoux, G. de Marsily, A. Barbreau, P. Calmels, B. Gaillard and R. Margritta, 1990b, Modeling fracture flow with a stochastic discrete fracture network: calibration and validation: 2. The transport model, Water Resour. Res. 26.3, 491-500.

6.

Carrera J., J. Heredia, S. Vomvoris and P. Hufschmied, 1990, Modeling of flow on a small fractured monzonitic gneiss block, Selected paper in Hydrogeolgy of low permeability Environments, Int. Assoc. of hydrogeologists, Hydrogeology. 2, 115-167.

7.

Dershowitz, W.S. and H.H. Einstein, 1987, Three-dimensional flow modeling in jointed rock masses. In: Herget, O., Vongpaisal, O. (Eds.), Proceedings of the Sixth Congress on ISRM, Montreal, Canada, 87-92.

8.

Dershowitz, W.S. and C. Fidelibus, 1999, Derivation of equivalent pipe network analogues for three-dimensional discrete fracture networks by the boundary element method, Water Resour. Res. 35.9, 2685-2691.

9.

Diodato, D.M., 1994. A compendium of Fracture Flow Models, 1994, Argonne National Laboratory Report, 88p.

10.

Dverstorp, B. and J. Andersson, 1989, Application of the discrete fracture network concept with field data: possibilities of model calibration and validation, Water Resour. Res. 25.3, 540-550.

11.

Elsworth, D., 1986a, A hybrid boundary element-finite element analysis procedure for fluid flow simulation in fractured rock masses, Int. J. Numer. Anal. Meth. Geomech. 10.6, 569-584.

12.

Elsworth, D., 1986b, A model to evaluate the transient hydraulic response of three-dimensional sparsely fractured rock masses, Water Resour. Res. 22.13, 1809-1819.

13.

Herbert, A.W., 1996, Modelling approaches for discrete fracture network flow analysis. In: Stephansson, O., Jing, L., Tang, C.F. (Eds.), Coupled Thermo-hydro-mechnical Processes of Fractured Media-mathematical and Experiment Studies, Elsevier, Amsterdam, 213-229.

14.

Hsieh, P.A. and S.P. Neuman, 1985, Field determination of the three dimensional hydraulic conductivity tensor of anisotropic media-1. Theory, Water Resour. Res. 21.11, 1655-1665.

15.

Jing, L. and J. Hudson, 2002, Numerical methods in rock mechanics, Int. J. Rock Mech. Min. Sci. 39.4, 409-427.

16.

Kantani, K., 1984, Distribution of directional data and fabric tensors, Int. J. Engng Sci. 22.2, 149-164.

17.

Kulatilake, P.H.S.W. and B.B. Panda, 2000, Effect of block size and joint geometry on jointed rock hydraulics and REV, J. Eng. Mech. 126, 850-858.

18.

Long, J.C.S., J.S. Remer, C.R. Wilson and P.A. Witherspoon, 1982, Porous Media Equivalents for networks of Discontinuous fractures, Water Resour. Res. 18.3, 645-658.

19.

Long, J.C.S., P. Gilmour and P.A. Witherspoon, 1985, A model for steady fluid flow in random three-dimensional networks of disc-shaped fractures, Water Resour. Res. 21.8, 1105-1115.

20.

Neuman, S.P. and J.S. Depner, 1988, Use of variable-scale pressure test data to estimate the log hydraulic conductivity covariance and dispersivity of fractured granites near Oracle, Arizona, J. Hydrol. 102, 475-501.

22.

Park, B.Y., K.S. Kim, C.S. Kim, D.S. Bae and H.K. Lee, 2001, Analysis of the pathways and travel times for groundwater in volcanic rock using 3D fracture network, J. of Korean Society for Rock Mech., 11, 42-58.

23.

Park, J.S., D.W. Ryu, C.H. Ryu and C.I. Lee, 2007, Groundwater flow analysis around hydraulic excavation damaged zone, J. of Korean Society for Rock Mech., 17, 109-118.

24.

Priest, S.D., 1993, Discontinuity Analysis for Rock Engineering, Chapman & Hall, London, 473p.

25.

Rouleau, A. and J.E. Gale, 1987, Stochastic discrete fracture simulation of ground water flow into an underground excavation in granite, Int. J. Rock Mech. Min. Sci. Geomech. Abstr. 24.2, 99-112.

26.

Schwartz, F.W., W.L. Smith and A.S. Crowe, 1983, A stochastic analysis of microscopic dispersion in fractured media, Water Resour. Res. 19.5, 1253-1265.

27.

Shapiro, A.M. and J. Andersson, 1985, Simulation of steady state flow in three dimensional fracture networks using boundary element method, Advances in Water Resour. 8.3, 106-110.

28.

Song, M.K., K.S. Jue and H.K. Moon, 1994, A theoretical and numerical study on channel flow in rock joints and fracture networks, J. of Korean Society for Rock Mech., 4, 1-16.

29.

Sudicky, E.A. and R.G. McLaren, 1992, The Laplace Transform Galerkin technique for large-scale simulation of mass transport in discretely fractured porous formations, Water Resour. Res. 28.2, 499-514.

30.

Wilcock, P., 1996, The NAPSAC fracture network code. In: Stephansson, O., Jing, L., Tang, C.F. (Eds.), Coupled Thermo-hydro-mechanical Processes of fractured Media, Elsevier, Rotterdam, 529-538.

31.

Zimmerman, R.W. and G.S. Bodvarsson, 1995, Effective Transmissivity of Two-dimensional Fracture Networks, LBL Report, 19p.