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미세균열의 간격 분포를 이용한 결의 평가 (III)

Evaluation for Rock Cleavage Using Distribution of Microcrack Spacings (III)

  • 박덕원 (한국지질자원연구원 전략기술연구본부)
  • Park, Deok-Won (Climate Change Mitigation and Sustainability Division, Korea Institute of Geoscience and Mineral Resources)
  • 투고 : 2016.10.19
  • 심사 : 2016.11.15
  • 발행 : 2016.12.31

초록

거창지역의 쥬라기 화강암에서 발달하는 결의 특성을 분석하였다. 3개 면 및 3개 결에 대한 평가는 (1) 간격의 값 그리고 길이의 값 사이의 감소비율, (2) 미세균열의 간격의 빈도수(N), (3) 총 간격($1mm{\geq}$), (4) 지수의 상수(a), (5) 지수(${\lambda}$)의 크기, (6) 평균 간격($S_{mean}$), (7) 평균 간격과 중앙 간격($S_{median}$) 사이의 차이 값($S_{mean}-S_{median}$) 및 (8) 간격의 밀도(${\rho}$)와 같은 파라미터를 이용하여 수행하였다. 특히 상기 간격의 파라미터 그리고 간격-누적빈도 도표에서 도출한 파라미터 사이의 밀접한 상관성을 도출하였다. 3개 채석면 그리고 3개 결을 대변하는 판별요소들은 이러한 상호 대비를 통하여 획득하였다. 이 연구의 분석 결과를 요약하면 다음과 같다. 첫째, 3개 결에 대한 빈도수, 평균값, 중앙값, 상기 차이값($S_{mean}-S_{median}$) 및 밀도의 감소비율은 G(2번 결, (G1 + G2)/2) < H(3번 결, (H1 + H2)/2) $\ll$ R(1번 결, (R1 + R2)/2), H < G $\ll$ R, H < G $\ll$ R, H < G < R 및 H < G $\ll$ R의 순이다. 3개 면에 대한 상기 5개 파라미터의 값은 R'(1번 면) $\ll$ H'(3번 면) < G'(2번 면), R' $\ll$ G'< H', R' < H' < G', R' < G' < H' 및 R' $\ll$ H' < G'의 다양한 순을 각각 보여준다. 둘째, (I) 파라미터(2, 3, 4 및 5) 및 (II) 파라미터(6, 7 및 8)의 값은 (I) H < G < R 및 (II) R < G < H의 순서이다. 반면에 3개 면에 대한 상기 두 그룹(I~II)의 파라미터의 값은 역순을 보여준다. 셋째, 여섯도표 사이의 전체적인 배열 특성을 살펴보면, 이들 도표들은 관계도에서 R2 < R1 < G2 < G1 < H2 < H1의 순을 보여 준다. 즉, 상기 여섯 도표는 1번 결(R1 + R2) < 2번 결(G1 + G2) < 3번 결(H1 + H2)의 순으로 요약될 수 있다. 이러한 결과는 미세균열의 간격과 관련된 결의 상대적인 강도를 지시한다. 특히 각 도표의 두 파라미터, 상기 차이값($S_{mean}-S_{median}$) 그리고 평균 간격은 도표 사이의 배열 순위의 예측에 대한 사전 정보를 제공할 수 있다. 마지막으로, 3개 면 그리고 3개 결의 종합도를 작성하였다. 관계도에서, 3개 결에 대한 3개 지수 직선의 순서는 R(R1 + R2) < G(G1 + G2) < H(H1 + H2)의 순을 보여준다. 반면에, 3개 면에 대한 3개 지수 직선은 H'(R2 + G2) < G'(R1 + H2) < R'(G1 + H1)의 순을 보여준다. 따라서 관계도로 부터 3개 면 및 3개 결 사이의 상호 역순의 상관성을 도출할 수 있다.

The characteristics of the rock cleavage in Jurassic granite from Geochang were analysed. The evaluation for three quarrying planes and three rock cleavages was performed using the parameters such as (1) reduction ratio between the value of spacing and the value of length, (2) microcrack spacing frequency(N), (3) total spacing($1mm{\geq}$), (4) exponential constant(a), (5) magnitude of exponent(${\lambda}$), (6) mean spacing($S_{mean}$), (7) difference value($S_{mean}-S_{median}$) between mean spacing and median spacing($S_{median}$) and (8) density of spacing. Especially the close dependence between the above spacing parameters and the parameters from the spacing-cumulative frequency diagrams was derived. The discrimination factors representing three quarrying planes and three rock cleavages were acquired through these mutual contrast. The analysis results of the research are summarized as follows. First, the reduction ratios of frequency(N), mean value, median value, the above difference value($S_{mean}-S_{median}$) and density for three rock cleavages are in orders of G(grain, (G1 + G2)/2) < H(hardway, (H1 + H2)/2) < R(rift, (R1 + R2)/2), H < G $\ll$ R, H < G $\ll$ R, H < G < R and H < G $\ll$ R. The values of the above five parameters for three planes show the various orders of R'(rift plane) $\ll$ H'(hardway plane) < G'(grain plane), R' $\ll$ G' < H', R' < H' < G', R' < G' < H' and R' $\ll$ H' < G', respectively. Second, the values of (I) parameters(2, 3, 4 and 5) and (II) parameters(6, 7 and 8) are in orders of (I) H < G < R and (II) R < G < H. On the contrary, the values of the above two groups(I~II) of parameters for three planes show reverse orders. Third, to review the overall characteristics of the arrangement among the six diagrams, these diagrams show an order of R2 < R1 < G2 < G1 < H2 < H1 from the related chart. In other words, above six diagrams can be summarized in order of rift(R1 + R2) < grain(G1 + G2) < hardway(H1 + H2). These results indicate a relative magnitude of rock cleavage related to microcrack spacing. Especially, two parameters for each diagram, the above difference value($S_{mean}-S_{median}$) and mean spacing, could provide advanced information for prediction the order of arrangement among the diagrams. Finally, the general chart for three planes and three rock cleavages were made. From the related chart, three exponential straight lines for three rock cleavages show an order of R(R1 + R2) < G(G1 + G2) < H(H1 + H2). On the contrary, three lines for three planes show an order of H'(R2 + G2) < G'(R1 + H2) < R'(G1 + H1). Consequently, correlation of the mutually reverse order between three planes and three rock cleavages can be drawn from the related chart.

키워드

참고문헌

  1. Baecher, G.B., Lanney, N.A., and Einstein, H.H., 1978, Statistical description of rock properties and sampling. 18th US symposium on rock mechanics.
  2. Barton, C.A. and Zoback, M.D., 1992, Self-similar distribution and properties of macroscopic fractures at depth in crystalline rock in the Cajon Pass Scientific Hole. Journal of Geophysical Research, 97, 5181-5200. https://doi.org/10.1029/91JB01674
  3. Bloomfield, J., 1996, Characterization of hydrogeologically significant fracture distributions in the Chalk: an example from the Upper Chalk of southern England. Journal of hydrology, 184, 355-379. https://doi.org/10.1016/0022-1694(95)02954-0
  4. Dunne, J.A., Williams, R.J., and Martinez, N.D., 2002, Food-web structure and network theory: The role of connectance and size. Proceedings of the National of Sciences of the United States of America (PNAS), 99, 12917-12922.
  5. Freire-Lista, D.M. and Fort, R., 2015, Anisotropy in Alpedrete granite cutting (Rift, Grain and Hardway directions) and effect on bush hammered heritage ashlars. Geophysical Research Abstracts, 17, EGU2015-9426-1, EGU General Assembly.
  6. Gale, J.E., Schaefer, R.A., Carpenter, A.B., and Herbert, A., 1991, Collection, analysis, and integration of discrete fracture data from the Monterey Formation for fractured reservoir. SPE Annual Technical Conference and Exhibition Formation Evaluation and Reservoir Geology.
  7. Galla, B.L., Tshosoa, G., Dymentb, J., Kampunzuc, A.B., Jourdand, F., Féraudd, G., Bertrande, H., Aubourgf, C., and Vetela, W., 2005, The Okavango giant mafic dyke swarm (NE Botswana): its structural significance within the Karoo Large Igneous Province. Journal of Structural Geology, 27, 2234-2255. https://doi.org/10.1016/j.jsg.2005.07.004
  8. Gillespie, P.A., Howard, C.B., Walsh, J.J., and Watterson, J., 1993, Measurement and characterisation of spatial distributions of fractures. Tectonophysics, 226, 113-141. https://doi.org/10.1016/0040-1951(93)90114-Y
  9. Gross, M.R. and Engelder, T., 1995, Strain accommodated by brittle failure in adjacent units of the Monterey Formation, U.S.A.: scale effects and evidence for uniform displacement boundary conditions. Journal of Structural Geology, 17, 1303-1318. https://doi.org/10.1016/0191-8141(95)00011-2
  10. Kim, Y.K. and Ro, B.D., 1989, Mechanical properties of discontinuous rocks in Upper Kyeongsang Supergroup. Journal of the Geological Society of Korea, 25, 392-404.
  11. Miller, N.C., 1993, Predicting flow characteristics of a lixiviant in a fractured crystalline rock mass. Report of investigations 9457, US Bureau of Mines, 24.
  12. Olson, J.E., Qiu, Y., Holder, J., and Rijken, P., 2001, Constraining the spatial distribution of fracture networks in naturally fractured reservoirs using fracture mechanics and core measurements. Society of Petroleum Engineers( SPE). SPE annual technical conference and exhibition, New Orleans, Louisiana, SPE 71342.
  13. Park, D.W., 2007, Orientations of vertical rift and grain planes in Mesozoic granites, Korea. The Journal of the Petrological Society of Korea, 16, 12-26.
  14. Park, D.W., 2011, Characteristics of the rock cleavage in Jurassic granite, Hapcheon. The Journal of the Petrological Society of Korea, 20, 219-230. https://doi.org/10.7854/JPSK.2011.20.4.219
  15. Park, D.W., 2015a, Characteristics of the rock cleavage in Jurassic granite, Geochang. The Journal of the Petrological Society of Korea, 24, 153-164. https://doi.org/10.7854/JPSK.2015.24.3.153
  16. Park, D.W., 2015b, Evaluation for rock cleavage using distribution of microcrack lengths. The Journal of the Petrological Society of Korea, 24, 165-180. https://doi.org/10.7854/JPSK.2015.24.3.165
  17. Park, D.W., 2016a, Evaluation for rock cleavage using distribution of microcrack spacings (I). The Journal of the Petrological Society of Korea, 25, 13-27. https://doi.org/10.7854/JPSK.2016.25.1.13
  18. Park, D.W., 2016b, Evaluation for rock cleavage using distribution of microcrack spacings (II). The Journal of the Petrological Society of Korea, 25, 151-163. https://doi.org/10.7854/JPSK.2016.25.2.151
  19. Park, D.W., Kim, H.C., Lee, C.B., Hong, S.S., Chang, S.W. and Lee, C.W., 2004, Characteristics of the rock cleavage in Jurassic granite, Pocheon. The Journal of the Petrological Society of Korea, 13, 133-141.
  20. Park, D.W., Seo, Y.S., Jeong, G.C. and Kim, Y.K., 2001, Microscopic analysis of the rock cleavage for Jurassic granite in Korea. The Journal of Engineering Geology, 11, 51-62.
  21. Pearce, M.A., Jones, R.R., Smith, S.A.F. and McCaffrey, K.J.W., 2011, Quantification of fold curvature and fracturing using terrestrial laser scanning. AAPG Bulletin, 95, 771-794. https://doi.org/10.1306/11051010026
  22. Priest, S.D. and Hudson, J.A., 1976, Discontinuity spacings in rock. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 13, 135-148.
  23. Rives, T., Razack, M., Petit, J.P. and Rawnsley, K.D., 1992, Joint spacing: analogue and numerical simulations. Journal of Structural Geology, 14, 925-937. https://doi.org/10.1016/0191-8141(92)90024-Q
  24. Rouleau, A. and Gale, J.E., 1985, Statistical characterization of the fracture system in the Stripa Granite, Sweden. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 22, 353-367. https://doi.org/10.1016/0148-9062(85)90001-4
  25. Sanderson, D.J., Roberts, S., Gumiel, P. and Greenfield. C., 2008, Quantitative analysis of tin- and tungsten-bearing sheeted vein systems. Economic Geology, 103, 1043-1056. https://doi.org/10.2113/gsecongeo.103.5.1043
  26. Segall, P., 1984, Formation and growth of extensional fracture sets. Geological Society of America Bulletin, 95, 454-462. https://doi.org/10.1130/0016-7606(1984)95<454:FAGOEF>2.0.CO;2
  27. Seo, Y.S., 2000, Stress relaxation test of granite under water-saturated triaxial condition. The Journal of Engineering Geology, 10, 217-223.
  28. Seo, Y.S. and Jeong, G.C., 1999, Micro-damage process in granite under the state of water-saturated triaxial compression. The Journal of Engineering Geology, 9, 243-251.
  29. Seo, Y.S. and Park, D.W., 2003, Mechanical anisotropy of Jurassic granites in Korea. The Journal of Engineering Geology, 13, 257-266.
  30. Seok, C.K. and Kim, Y.K., 1991, Discontinuous properties of Jurassic and Cretaceous granites, Korea. Journal of the Geological Society of Korea, 27, 123-135.