Tunnel and Underground Space (터널과지하공간)

Korean Society for Rock Mechanics and Rock Engineering (한국암반공학회)
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Research Trend of DFN Modeling Methodology: Representation of Spatial Distribution Characteristics of Fracture Networks

DFN 모델링 연구 동향 소개: 균열망의 공간적 분포 특성 모사를 중심으로

  • Jineon, Kim (Department of Energy Systems Engineering, Seoul National University) ;
  • Jiwon, Cho (Department of Energy Systems Engineering, Seoul National University) ;
  • iIl-Seok, Kang (Department of Energy Systems Engineering, Seoul National University) ;
  • Jae-Joon, Song (Department of Energy Systems Engineering, Seoul National University)
  • 김진언 (서울대학교 에너지시스템공학부) ;
  • 최지원 (서울대학교 에너지시스템공학부) ;
  • 강일석 (서울대학교 에너지시스템공학부) ;
  • 송재준 (서울대학교 에너지시스템공학부)
  • Received : 2022.12.12
  • Accepted : 2022.12.15
  • Published : 2022.12.31
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Abstract

DFN (discrete fracture network) models that take account of spatial variability and correlation between rock fractures have been demanded for analysis of fractured rock mass behavior for wide areas with high reliability, such as that of underground nuclear waste repositories. In this regard, this report describes the spatial distribution characteristics of fracture networks, and the DFN modeling methodologies that aim to represent such characteristics. DFN modeling methods have been proposed to represent the spatial variability of rock fractures by defining fracture domains (Darcel et al., 2013) and the spatial correlation among fractures by genetic modeling techniques that imitate fracture growth processes (Davy et al., 2013, Libby et al., 2019, Lavoine et al., 2020).These methods, however, require further research for their application to field surveys and for modeling in-situ rock fracture networks.

DFN (discrete fracture network, 불연속균열망) 모델은 암반의 복합거동 분석을 위한 불연속암반 모사체로, 다양한 불연속암반의 수리-역학적 거동 해석 연구에 활용되어 왔다. 최근 들어서는 방사성폐기물 심층처분장에서의 불연속암반 거동 해석과 같이 대규모 영역을 대상으로 하거나 높은 신뢰도를 갖춰야 하는 DFN 모델링을 위해 암반균열망의 공간적 분산과 균열 간의 공간적 상관성을 구현하는 DFN 모델링 기법이 요구되고 있다. 본 기술보고에서는 DFN 모델의 기하학적 모델링에 초점을 두어 암반균열망 모델링의 방법론을 정리 및 소개하고, 암반균열망의 공간적 분포 특성의 유형과 이를 DFN 모델링에 반영하기 위해 제안된 모델링 기법들의 현황과 한계점을 검토하였다. 암반균열망의 공간적 분산을 고려하기 위해 암반 공간을 균열 영역(fracture domain)으로 분할하는 기법(Darcel et al., 2013)과 균열 간의 공간적 상관성을 재현하기 위해 균열의 발생과정을 모사하여 DFN 모델을 생성하는 발생학적 모델링 기법(genetic modeling)(Davy et al., 2013, Libby et al., 2019, Lavoine et al., 2020)이 제안되었으며, 각 기법의 한계점을 검토한 결과, 모델링 기법의 적용성을 개선하는 추후 연구가 필요한 것으로 파악되었다.

Keywords

Acknowledgement

본 연구는 2022년도 정부(산업통상자원부)의 재원으로 해외자원개발협회의 지원(2021060003, 스마트 마이닝 전문 인력 양성)과 정부(과학기술정보통신부)의 재원으로 한국연구재단의 지원(No. 2022R1F1A1076409)을 받아 수행된 연구입니다.

References

  1. Barton, N., 1978, Suggested methods for the quantitative description of discontinuities in rock masses. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 15, 319-368.  https://doi.org/10.1016/0148-9062(78)91472-9
  2. Berkowitz, B., 2002, Characterizing flow and transport in fractured geological media: A review. Advances in Water Resources, 25(8), 861-884.  https://doi.org/10.1016/S0309-1708(02)00042-8
  3. Cruden, D., 1977, Describing the size of discontinuities. Proceedings of International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 14(3), 133-137.  https://doi.org/10.1016/0148-9062(77)90004-3
  4. Darcel, C., Davy, P., Bour, O., and de Dreuzy, J.R., 2006, Discrete fracture network for the Forsmark site. SKB, Solna, Sweden. 
  5. Darcel, C., Le Goc, R., and Davy, P., 2013, Development of the statistical fracture domain methodology - application to the Forsmark site. SKB, Solna, Sweden. 
  6. Davy, P., Le Goc, R., Darcel, C., Bour, O., de Dreuzy, J.R., and Munier, R., 2010, A likely universal model of fracture scaling and its consequence for crustal hydromechanics. Journal of Geophysical Research: Solid Earth, 115, B10411 
  7. Davy, P., Darcel, C., Le Goc, R., Munier, R., Selroos, J.O., and Ivars, D.M., 2018, DFN, why, how and what for, concepts, theories and issues. Paper presented at the 2nd International Discrete Fracture Network Engineering Conference, Seattle, USA. 
  8. Davy, P., Le Goc, R., and Darcel, C., 2013, A model of fracture nucleation, growth and arrest, and consequences for fracture density and scaling. Journal of Geophysical Research: Solid Earth, 118, 1393-1407.  https://doi.org/10.1002/jgrb.50120
  9. Dershowitz, W., Baecher, G., and Einstein, H., 1979, Prediction of rock mass deformability. In Proceedings of the 4th ISRM Congress, Montreux, Switzerland, 1, 605-611. 
  10. Evans, M., Hastings, N., and Peacock, B., 1993, Statistical distributions. Wiley, New York. 
  11. Fisher, R., 1953. Dispersion on a sphere. Royal Society of London Proceedings, 217, 295-305.  https://doi.org/10.1098/rspa.1953.0064
  12. Hudson, J. and Priest, S.D., 1979, Discontinuities and rock mass geometry. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 16, 339-362.  https://doi.org/10.1016/0148-9062(79)90001-9
  13. Kulatilake, P.H.S.W., Wathugala, D.N., and Stephansson, O., 1993, Joint Network Modelling with a Validation Exercise in Stripa Mine, Sweden. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 30(5), 503-526.  https://doi.org/10.1016/0148-9062(93)92217-E
  14. Lavoine, E., Davy, P., Darcel, C., and Munier, R., 2020, A discrete fracture network model with stress-driven nucleation: impact on clustering, connectivity, and topology. Frontiers in Physics. doi:10.3389/fphy.2020.00009. 
  15. Lee, Y.K. and Song, J.J., 2019, Calculation of Joint Center Volume (JCV) for Estimation of Joint Size Distribution in Non-Planar Window Survey. Tunnel and Underground Space, 29(2), 89-107.  https://doi.org/10.7474/TUS.2019.29.2.089
  16. Libby, S., Hartley, L., Turnbull, R., Cottrell, M., Bym, T., Josephson, N., Munier, R., Selroos, J.-O., and Ivars, D.M., 2019, Grown Discrete Fracture Networks: A new method for generating fractures according to their deformation history. In Proceedings of the 53rd US Rock Mechanics/Geomechanics Symposium, June 2019, New York City. 
  17. Maillot, J., Davy, P., Le Goc, R., Darcel, C., and Dreuzy, J.R., 2016, Connectivity, permeability, and channeling in randomly distributed and kinematically defined discrete fracture network models. Water Resources Research, 52(11), 8526-8545.  https://doi.org/10.1002/2016WR018973
  18. Min, K.B. and Stephansson, O., 2011, The DFN-DEM Approach Applied to Investigate the Effects of Stress on Mechanical and Hydraulic Rock Mass Properties at Forsmark, Sweden. Tunnel and Underground Space, 21(2), 117-127.  https://doi.org/10.7474/TUS.2011.21.2.117
  19. Neuman, S., 2005, Trends, prospects and challenges in quantifying flow and transport through fractured rocks. Hydrogeology Journal, 13(1), 124-147.  https://doi.org/10.1007/s10040-004-0397-2
  20. Park, J.C., Park, S.H., Kim, H.Y., Kim, G.Y., and Kwon, S., 2015, Sensitivity Analysis of Three-Dimensional Discrete Fracture Network Modeling or Rock Mass. Tunnel and Underground Space, 25(4), 341-358.  https://doi.org/10.7474/TUS.2015.25.4.341
  21. Park, J.S., Ryu, D.W., Ryu, C.H., and Lee, C.I., 2007, Groundwater Flow Analysis around Hydraulic Excavation Damaged Zone. Tunnel and Underground Space, 17(2), 109-118. 
  22. Park, J., Kim, J.S., Lee, C., Kwaon, S., 2019, Hydraulic Analysis of a Discontinuous Rock Mass Using Smeared Fracture Model and DFN Model. Tunnel and Underground Space, 29(5), 318-331.  https://doi.org/10.7474/TUS.2019.29.5.318
  23. Priest, S.D., 1993, Discontinuity Analysis for Rock Engineering. Chapman & Hall, London.
  24. Priest, S.D. and Hudson, J.A., 1981, Estimation of discontinuity spacings and trace length using scanline surveys. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 18, 183-197.  https://doi.org/10.1016/0148-9062(81)90973-6
  25. Ren, F., Ma, G., Fan, L., Wang, Y., and Zhu, H., 2017, Equivalent discrete fracture networks for modelling fluid flow in highly fractured rock mass. Engineering Geology, 229, 21-30.  https://doi.org/10.1016/j.enggeo.2017.09.013
  26. Rippon, J.H., 1985, Contoured patterns of the throw and hade of normal faults in the Coal Measures (Westphalian) of north-east Derbyshire. Proceedings of the Yorkshire Geological Society, 45, 147-161.  https://doi.org/10.1144/pygs.45.3.147
  27. Ryu, S., Um, J.G., and Park, J., 2020, Estimation of Strength and Deformation Modulus of 3-D DFN System Using the Distinct Element Method. Tunnel and Underground Space, 30(1), 15-28.  https://doi.org/10.7474/TUS.2020.30.1.015
  28. Saevik, P. and Nixon, C., 2017, Inclusion of topological measurements into analytic estimates of effective permeability in fractured media. Water Resources Research, 53, 9424-9443.  https://doi.org/10.1002/2017WR020943
  29. Sanderson, D.J. and Nixon, C.W., 2015, The use of topology in fracture network characterization. Journal of Structural Geology, 72, 55-66.  https://doi.org/10.1016/j.jsg.2015.01.005
  30. Segall, P. and Pollard, D.D., 1983, Joint formation in granitic rock of the Sierra Nevada. Geological Society of America Bulletin, 94, 563-575.  https://doi.org/10.1130/0016-7606(1983)94<563:JFIGRO>2.0.CO;2
  31. Selroos, J.O., Ivars, D.M., Munier, R., Hartley, L., Libby, S., Davy, P., Darcel, C., and Trinchero, P., 2022, Methodology for discrete fracture network modelling of the Forsmark site: Part 1 - concepts, data and interpretation methods. SKB, Solna, Sweden. 
  32. Spyropoulos, C., Griffith, W.J., Scholz, C.H., and Shaw, B.E., 1999, Experimental evidence for different strain regimes of crack populations in a clay model. Geophysical Research Letters, 26, doi:10.1029/1999gl900175. 
  33. Tsang, C.-F. and Neretnieks, I., 1998, Flow channeling in heterogeneous fractured rocks, Review of Geophysics. 36(2), 275-298.  https://doi.org/10.1029/97RG03319
  34. Walsh, J.J. and Watterson, J., 1998, Analysis of the relationship between displacements and dimensions of faults. Journal of Structural Geology, 10, 239-247.  https://doi.org/10.1016/0191-8141(88)90057-0
  35. Xiong, F., Sun, H., Zhang, Q., Wang, Y., and Jiang, Q., 2022, Preferential flow in three-dimensional stochastic fracture networks: The effect of topological structure. Engineering Geology, 309, 106856. 
  36. Zhang, L. and Einstein, H.H., 2000, Estimating the intensity of rock discontinuities. International Journal of Rock Mechanics and Mining Sciences, 37, 819-837.  https://doi.org/10.1016/S1365-1609(00)00022-8