상온 및 고온 하 진삼축압축실험을 이용한 시추공의 파괴 거동 기초 연구

국문 초록 (Abstract)

본 연구에서는 현지 암반의 진삼축 응력 조건과 온도 변화를 고려한 공벽 안정성 실험을 수행하고, 심부지하의 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°C~100°C로 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.

다국어 초록 (Multilingual Abstract)

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°C. 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.

목차 (Table of Contents)

• ABSTRACT
• 초록
• 1. 서론
• 2. 이론적 배경
• 3. 상온 및 고온 하의 진삼축압축실험에 의한 공벽 파괴
• 4. 실험 결과
• 5. 결과 분석
• 6. 결론
• REFERENCES

참고문헌 (Reference)

1 Ewy, R. T., "Wellbore-stability predictions by use of a modified Lade criterion" 14 (14): 85-91, 1999

2 Zoback, M. D., "Wellbore breakouts and in situ stress" 90 (90): 5523-5530, 1985

3 Hoek, E., "Underground Excavations in Rock" Institute of Mining and Metallurgy 1980

4 Jansen, D. P., "Ultrasonic imaging and acoustic emission monitoring of thermally induced microcracks in Lac du Bonnet granite" 98 (98): 22231-22243, 1993

5 윤동영, "Thermomechanical borehole stability analysis by true triaxial experiment and discrete element modeling" Seoul National University 2019

6 Liu, Q., "The role of flaws on crack growth in rock-like material assessed by AE technique" 193 (193): 99-115, 2015

7 Al-Ajmi, A. M., "Stability analysis of vertical boreholes using the Mogi–Coulomb failure criterion" 43 (43): 1200-1211, 2006

8 Fakhimi, A., "Simulation of failure around a circular opening in rock" 39 (39): 507-515, 2002

9 Martin, C. D., "Seventeenth Canadian geotechnical colloquium : the effect of cohesion loss and stress path on brittle rock strength" 34 (34): 698-725, 1997

10 Al-Ajmi, A. M., "Relation between the Mogi and the Coulomb failure criteria" 42 (42): 431-439, 2005

11 Haimson, B., "Micromechanisms of borehole instability leading to breakouts in rocks" 44 (44): 157-173, 2007

12 Lee, M., "Laboratory study of borehole breakouts in Lac du Bonnet granite: a case of extensile failure mechanism" 30 (30): 1039-1045, 1993

13 Haimson, B. C., "Laboratory study of borehole breakouts in Cordova Cream: a case of shear failure mechanism" 30 (30): 1047-1056, 1993

14 Barton, C. A., "In-situ stress orientation and magnitude at the Fenton Geothermal Site, New Mexico, determined from wellbore breakouts" 15 (15): 467-470, 1988

15 Mogi, K., "Fracture and flow of rocks under high triaxial compression" 76 (76): 1255-1269, 1971

16 Zhuang, L., "Evaluation of water saturation effect on mechanical properties and hydraulic fracturing behavior of granite" 130 : 104321-, 2020

17 Mogi, K., "Effect of the intermediate principal stress on rock failure" 72 (72): 5117-5131, 1967

18 Single, B., "Effect of intermediate principal stress on strength of anisotropic rock mass" 13 (13): 71-79, 1998

19 Maury, V. M., "Borehole instability: case histories, rock mechanics approach, and results" 11-24, 1987

20 Guenot, A., "Borehole breakouts and stress fields" 26 (26): 185-195, 1989

21 Zheng, Z., "Analysis of borehole breakouts" 94 (94): 7171-7182, 1989

22 Colmenares, L. B., "A statistical evaluation of intact rock failure criteria constrained by polyaxial test data for five different rocks" 39 (39): 695-729, 2002