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상온 및 고온 하 진삼축압축실험을 이용한 시추공의 파괴 거동 기초 연구

A Basic Study on Borehole Breakout under Room Temperature and High Temperature True Triaxial Compression

  • 윤정환 (서울대학교 에너지시스템공학부) ;
  • 민기복 (서울대학교 에너지시스템공학부) ;
  • 박의섭 (한국지질자원연구원 지질환경연구본부 심지층연구센터) ;
  • 정용복 (한국지질자원연구원 지질환경연구본부 심지층연구센터)
  • Yoon, Jeonghwan (Department of Energy Systems Engineering, Seoul National University) ;
  • Min, Ki-Bok (Department of Energy Systems Engineering, Seoul National University) ;
  • Park, Eui-Seob (Deep Subsurface Research Center, Geologic Environment Division, Korea Institute of Geoscience of Mineral Resources) ;
  • Jung, Yong-Bok (Deep Subsurface Research Center, Geologic Environment Division, Korea Institute of Geoscience of Mineral Resources)
  • 투고 : 2020.12.10
  • 심사 : 2020.12.23
  • 발행 : 2020.12.31

초록

본 연구에서는 현지 암반의 진삼축 응력 조건과 온도 변화를 고려한 공벽 안정성 실험을 수행하고, 심부 지하의 응력 조건과 압력 조건에서 암석의 열역학적 거동을 관찰하였다. 중국 황색 사암과 국내 황등 화강암 시료를 이용하여 진삼축압축실험을 진행하였다. 역학 실험은 각각 9가지 구속압 조건에서 수행되었고 열역학 실험은 화강암 시료를 이용하여 6가지 구속압 조건에서 시료를 60℃~100℃로 가열하여 수행하였다. 역학 실험 결과 공벽 파괴가 발생하는 최대 주응력은 중간 주응력에 비례하는 것을 확인하였다. 열역학 실험에서는 온도 증가에 따라 공벽의 응력장에 열응력이 추가되어 공벽 파괴가 추가적으로 발생하는 것을 확인하였다. 실내 실험 결과를 분석하기 위해 모기쿨롱 파괴 기준식을 사용하여 분석하였다. 원통형 시료에 대한 전통적인 삼축압축시험 결과와 진삼축 조건 하의 공벽 파괴 실험 결과가 모두 진삼축 파괴 기준식인 모기쿨롱 파괴 기준식에 잘 부합됨을 확인하였다.

This paper performs laboratory experiments for borehole stability considering temperature and true triaxial stress condition, and observes a thermo-mechanical behavior of the rock under stress and temperature conditions of deep underground. China yellow sandstone and Hwangdeung granite specimens were used to perform a true triaxial compression test. Mechanical tests were carried out under nine confining pressure conditions, and thermo-mechanical tests using granite samples were carried out under six confining pressure conditions at 60-100℃. In the mechanical tests, maximum principal stress at borehole breakout was proportional to intermediate principal stress. In the thermo-mechanical tests, it was confirmed that thermal stress is added to the stress field of the borehole with the increase in temperature, resulting in additional breakout progress. To analyze the results of the laboratory experiment, Mogi-Coulomb failure criterion was used. The results of traditional triaxial compression test on cylindrical specimens and borehole breakout under true triaxial compressions matched well with Mogi-Coulomb failure criterion.

키워드

과제정보

본 논문은 한국지질자원연구원(KIGAM)의 지원을 받아 수행한 연구 과제입니다(GP2020-010). 논문 작성을 위한 서울대학교 공학연구원의 지원에 감사드립니다.

참고문헌

  1. 윤동영, 2019, Thermomechanical borehole stability analysis by true triaxial experiment and discrete element modeling (Master's thesis, Seoul National University).
  2. Al-Ajmi, A. M., & Zimmerman, R. W., 2005, Relation between the Mogi and the Coulomb failure criteria. International Journal of Rock Mechanics and Mining Sciences, 42(3), 431-439. https://doi.org/10.1016/j.ijrmms.2004.11.004
  3. Al-Ajmi, A. M., & Zimmerman, R. W., 2006, Stability analysis of vertical boreholes using the Mogi-Coulomb failure criterion, International Journal of Rock Mechanics and Mining Sciences, 43(8), 1200-1211. https://doi.org/10.1016/j.ijrmms.2006.04.001
  4. Barton, C. A., Zoback, M. D., & Burns, K. L., 1988, In-situ stress orientation and magnitude at the Fenton Geothermal Site, New Mexico, determined from wellbore breakouts, Geophysical Research Letters, 15(5), 467-470. https://doi.org/10.1029/GL015i005p00467
  5. Colmenares, L. B., & Zoback, M. D., 2002, A statistical evaluation of intact rock failure criteria constrained by polyaxial test data for five different rocks, International Journal of Rock Mechanics and Mining Sciences, 39(6), 695-729. https://doi.org/10.1016/S1365-1609(02)00048-5
  6. Ewy, R. T., 1999, Wellbore-stability predictions by use of a modified Lade criterion, SPE Drilling & Completion, 14(02), 85-91. https://doi.org/10.2118/56862-PA
  7. Fakhimi, A., Carvalho, F., Ishida, T., & Labuz, J. F., 2002, Simulation of failure around a circular opening in rock. International Journal of Rock Mechanics and Mining Sciences, 39(4), 507-515. https://doi.org/10.1016/S1365-1609(02)00041-2
  8. Guenot, A., 1989, Borehole breakouts and stress fields, In International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 26(3-4), 185-195. https://doi.org/10.1016/0148-9062(89)91968-2
  9. Haimson, B., 2007, Micromechanisms of borehole instability leading to breakouts in rocks, International Journal of Rock Mechanics and Mining Sciences, 44(2), 157-173. https://doi.org/10.1016/j.ijrmms.2006.06.002
  10. Haimson, B. C., & Song, I., 1993, Laboratory study of borehole breakouts in Cordova Cream: a case of shear failure mechanism, In International journal of rock mechanics and mining sciences & geomechanics abstracts, 30(7), 1047-1056. https://doi.org/10.1016/0148-9062(93)90070-T
  11. Hoek, E., and E.T. Brown, Underground Excavations in Rock, Institute of Mining and Metallurgy, London, 1980.
  12. Jansen, D. P., Carlson, S. R., Young, R. P., & Hutchins, D. A., 1993, Ultrasonic imaging and acoustic emission monitoring of thermally induced microcracks in Lac du Bonnet granite, Journal of Geophysical Research: Solid Earth, 98(B12), 22231-22243. https://doi.org/10.1029/93JB01816
  13. Lee, M., & Haimson, B., 1993, Laboratory study of borehole breakouts in Lac du Bonnet granite: a case of extensile failure mechanism, In International journal of rock mechanics and mining sciences & geomechanics abstracts, 30(7), 1039-1045. https://doi.org/10.1016/0148-9062(93)90069-P
  14. Liu, Q., Xu, J., Liu, X., Jiang, J., & Liu, B., 2015, The role of flaws on crack growth in rock-like material assessed by AE technique, International Journal of Fracture, 193(2), 99-115. https://doi.org/10.1007/s10704-015-0021-6
  15. Martin, C. D., 1997, Seventeenth Canadian geotechnical colloquium: the effect of cohesion loss and stress path on brittle rock strength, Canadian Geotechnical Journal, 34(5), 698-725. https://doi.org/10.1139/t97-030
  16. Maury, V. M., & Sauzay, J., 1987, Borehole instability: case histories, rock mechanics approach, and results, SPE/IADC drilling conference, Society of Petroleum Engineers. SPE/IADC 16051, 11-24.
  17. Single, B., Goel, R. K., Mehrotra, V. K., Garg, S. K., & Allu, M. R., 1998, Effect of intermediate principal stress on strength of anisotropic rock mass. Tunnelling and Underground Space Technology, 13(1), 71-79. https://doi.org/10.1016/S0886-7798(98)00023-6
  18. Mogi, K., 1967, Effect of the intermediate principal stress on rock failure, Journal of Geophysical Research, 72(20), 5117-5131. https://doi.org/10.1029/JZ072i020p05117
  19. Mogi, K., 1971, Fracture and flow of rocks under high triaxial compression, Journal of Geophysical Research, 76(5), 1255-1269. https://doi.org/10.1029/JB076i005p01255
  20. Zheng, Z., Kemeny, J., & Cook, N. G., 1989, Analysis of borehole breakouts, Journal of Geophysical Research: Solid Earth, 94(B6), 7171-7182. https://doi.org/10.1029/JB094iB06p07171
  21. Zhuang, L., Kim, K. Y., Diaz, M., & Yeom, S, 2020, Evaluation of water saturation effect on mechanical properties and hydraulic fracturing behavior of granite, International Journal of Rock Mechanics and Mining Sciences, 130, 104321. https://doi.org/10.1016/j.ijrmms.2020.104321
  22. Zoback, M. D., Moos, D., Mastin, L., & Anderson, R. N., 1985, Wellbore breakouts and in situ stress, Journal of Geophysical Research: Solid Earth, 90(B7), 5523-5530. https://doi.org/10.1029/JB090iB07p05523