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Research Article

Analysis of the Fracture Roughness of Crystalline Rock under Multi-stage Stress Conditions

다단계압력 환경하에서의 결정질 암석의 절리면 거칠기 변화 분석

Junghae Choi1*
,
Heyjin Kim2
최 정해1*
,
김 혜진2
1Professor, Department of Earth Science Education, Kyungpook National University
2Researcher, Kyungnam Branch Office, Human Resources Development Service of Korea
1경북대학교 지구과학교육과 교수
2한국산업인력공단 경남지사 연구원
*Corresponding Author
30 September 2019. pp. 237-249
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Abstract

The roughness changes on a fracture surface were analyzed via a multi-stage compression test under high temperatures to assess how the cracks in a rock mass affect groundwater movement. The analyzed samples consist of coarse granitic rocks from approximately 40 and 270 m depth, and fine granitic rocks from 500 m depth. The compression test was conducted on 20 × 40 × 5 mm samples using a loading system where the pressure increases in 10 MPa increments to 120 MPa. A high-resolution 3D confocal laser scanning microscope (CLSM) was used to observe the surface changes, including the roughness changes, at each pressure step. The roughness change was calculated based on the roughness factor. The experimental results indicate that the roughness of the fracture surface varies with rock type under the stepwise pressure conditions. These data provide a basis for predicting groundwater flow along rock fractures.

Keywords
fracture roughness
multi-stage compression test
roughness factor
confocal laser scanning microscope
deep underground disposal

본 연구에서는 지하수의 이동에 영향을 주는 암반의 균열에 대해서 고온하에서의 다단계 압력실험을 통해 균열면의 거칠기 변화에 대한 분석을 실시하였다. 연구에 사용된 시료는 지표에서 지하 500 m 구간에서 획득한 조립질 화성암과 세립질 화성암 시료 중 심도 약 40 m와 270 m의 시료를 실험에 사용하였다. 압력은 최대 120 MPa 까지 가압을 하였으며, 단계적으로 10 MPa씩 증가하면서 실험을 수행하였다. 각 단계에서의 표면 변화를 관측하기 위해서 고분해능 3차원 다초점 레이저 스캔 현미경(Confocal Laser Scanning Microscope, CLSM)을 사용하였으며, 이를 통해서 미세한 표면의 거칠기를 확인할 수 있었다. 거칠기의 변화에 대해서는 거칠기 인자값을 기준으로 변화된 양을 계산하였다. 본 실험에 사용된 시료는 20 × 40 × 5 mm 크기를 가지고 있으며, 가압장치는 나사방식으로 압력을 가할 수 있도록 제작한 챔버를 활용하여 실험을 수행하였다. 실험결과 단계적으로 압력이 가해지는 조건에서 압력에 따른 균열면의 거칠기는 입자의 크기에 따라 다른 변화를 보이는 것으로 확인되었으며, 이러한 자료는 추후 암석의 균열면을 따라 이동할 수 있는 지하수의 흐름에 대한 예측을 위한 기초자료로 활용 될 수 있을 것으로 기대한다.

키워드
균열 거칠기
다단계 압력
거칠기 인자
다초점 레이저 스캔 현미경
지층처분
References
1
Bae, K.Y., Lee, C.I., 2002, Development of a 3D roughness measurement system of rock joint using laser type displacement meter, Tunnel and Underground Space, 12(4), 268-276 (in Korean with English abstract).
2
Horii, H., Nemat-Nasser, S., 1986, Brittle failure in compression: splitting, faulting and brittle-ductile transition, International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 25(3), 337-374.
10.1098/rsta.1986.0101
3
Kim, D.B., Son, B.K., Lee, C.I., 2001, A numerical study of the shear behavior of a rock joint considering quantitative roughness parameters, Journal of the Korean Geotechnical Society, 17(4), 279-288 (in Korean with English abstract).
4
Kim, J.S., Lee, C.S., Choi, Y.C., Choi, H.J., 2014, Saturation prediction of bentonite buffer in a waste disposal repository, Proceedings of the KSNVE Annual Autumn Conference, 2014(10), Mokpo, 361-362.
5
Kim, J.T., Jeong, G.C., Kim, M.I., Song, J.Y., Park, C.K., 2004, Characterization of fracture roughness in coarse ‧ midium ‧ fine grained granite, The Journal of Engineering Geology, 14(2), 147-168 (in Korean with English abstract).
6
Kim, N.J., Lee, H.K., 1970, Explanatory text of the geological map of Jungpyeong dong sheet, Geological Survey of Korea, 26p.
7
Lee, M.H., Kim, J.W., Chang, K.T., 2007, The influence of rock joint roughness and normal stress on shear behaviour, Tunnel and Underground Space, 17(3), 186-196 (in Korean with English abstract).
8
Lee, S.D., Kang, J.H., Lee, C.I., 1994, Shear strength and deformation behavior of rock joint with roughness, Tunnel and Underground Space, 4(3), 261-274 (in Korean with English abstract).
9
Lu, W., Chakravarthula, S.S., Chen, J., Qiao, Y., 2012, Propagation of a cleavage crack front across a field of persistent grain boundaries, International Journal of Solids and Structures, 49(3), 584-589.
10.1016/j.ijsolstr.2011.11.003
10
Park, B.Y., Kim, K.S., Kim, C.S., Bae, D.S., Lee, H.K., 2001, Analysis of the patheways and travel times for groundwater in volcanic rock using 3D fracture network, Tunnel and Underground Space, 11(1), 42-58 (in Korean with English abstract).
11
Park, H.I., Lee, J.D., Cheong, J.G., 1977, Explanatory text of the geological map of Yuseong sheet, Geological Survey of Korea, 21p.
12
Reyes, O., Einstein, H.H., 1991, Failure mechanisms of fractured rock - A fracture coalescence model, Conference Proceedings of 7th ISRM Congress, Aachen, Germany, 333-340.
13
Shen, B., 1995, The mechanism of fracture coalescence in compression-experimental study and numerical simulation, Engineering Fracture Mechanics, 51(1), 73-85.
10.1016/0013-7944(94)00201-R
Information
  • Publisher :Korean Society of Engineering Geology
  • Publisher(Ko) :대한지질공학회
  • Journal Title :The Journal of Engineering Geology
  • Journal Title(Ko) :지질공학
  • Volume : 29
  • No :3
  • Pages :237-249
  • Received Date : 2019-08-22
  • Revised Date : 2019-09-11
  • Accepted Date : 2019-09-11
  • DOI :https://doi.org/10.9720/kseg.2019.3.237
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