Journal of the Korean GEO-environmental Society (한국지반환경공학회 논문집)

Korean Geo-Environmental Society (한국지반환경공학회)
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Creep Characteristics of Mudstone According to Stress Level and Water Content

응력수준 및 함수비에 따른 이암의 Creep 특성에 관한 연구

  • 이영휘 (영남대학교 건설시스템공학과) ;
  • 정강복 ((주)도담이앤씨종합건축사사무소)
  • Published : 2012.03.01
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Abstract

The time-dependent characteristics of mudstone in this study were analyzed by performing creep tests for the mudstone in Pohang. The creep tests were conducted on various boundary conditions to observe the time-dependent behavior of mudstone and the results were compared with values predicted by established visco-elastic model and empirical equations. As a result of analysis for empirical equations proposed by Griggs(1936), Cottrell(1952) and Singh(1975), the creep constants generally tend to increase as increasing the stress level and water content. Moreover, the values predicted by Singh's equation were well fitted for the test results. Therefore, it is expected to be reasonable that creep behavior of mudstone is analyzed using Singh's equation. As a result of analysis for a Burger's model, the predicted values were well fitted for the test results. Therefore, it is expected be reasonable that the creep behavior of mudstone by a rheological model is analyzed using Burger's model.

본 연구에서는 포항이암을 대상으로 다양한 경계조건에서의 creep 시험을 수행하여 이암의 시간의존적 특성을 분석하였으며, 이를 바탕으로 기존에 발표된 creep에 대한 점탄성 모델 및 경험식들과 비교 분석함으로써 더 합리적으로 creep 특성을 평가할 수 있는 방법을 제안하고자 한다. Creep 시험결과를 Griggs(1936), Cottrell(1952) 및 Singh(1975)이 제안한 경험식에 대하여 분석한 결과, 전반적으로 응력수준 및 함수비가 증가할수록 creep 상수가 증가하는 경향을 나타내었다. 또한, Singh의 경험식에 의한 예측치는 실측치와 매우 높은 상관성을 보이고 있는 것을 확인할 수 있었으며, 이로부터 이암의 크리프 거동을 해석함에 있어 Singh의 경험식을 적용함이 바람직할 것으로 판단된다. 유동학적 모델인 Burger 모델에 의한 예측치와 실측치를 비교한 결과, 매우 좋은 일치를 보이고 있음을 알 수 있으며, 이로부터 이암의 크리프 거동을 해석함에 있어 Maxwell 요소와 Kelvin 요소를 직렬로 연결한 Burger 모델을 적용하는 것이 바람직할 것으로 판단된다.

Keywords

References

  1. 이영휘, 김용준(2003), 암반의 경계조건을 고려한 절리면 직접전단시험기 개발, 한국지반공학회지 논문집, 제19권 제2호, pp. 147-157.
  2. 정강복(2006), 포항지역 이암의 공학적 특성 및 변형거동에 관한 연구, 박사학위 논문, 영남대학교, pp. 198-207.
  3. Chin, Han-Ping and Rogers, J. D.(1987), Creep Parameters of Rocks on an Engineering Scale, Rock Mechanics and Rock Engineering, Vol. 20, No. 2, pp. 137-146.
  4. Cottrell, A. H.(1952), The Time Laws of Creep, Journal of the Mechanics and Physics of Solids, Vol. 1, No. 1, pp. 53-63. https://doi.org/10.1016/0022-5096(52)90006-9
  5. Griggs, D. T.(1936), Deformation of Rocks under High Confining Pressure, Journal of Geology, Vol. 44, No. 5, pp. 541-577. https://doi.org/10.1086/624455
  6. Hardy, H. R., JR., Kim, R. Y., Stefanko, R. and Wang, Y. J. (1970), Creep and Micro-seismic Activity in Geologic Materials, Proceedings, 11th Symposium on Rock Mechanics(AIME), Berkeley, CA, pp. 377-414.
  7. Kaiser, P. K. and Morgenstern, N. R.(1981), Phenomenological Model for Rock with Time-dependent Strength, International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts, Vol. 18, No. 2, pp. 153-165. https://doi.org/10.1016/0148-9062(81)90740-3
  8. Lomnitz, C.(1956), Creep Measurement in Igneous Rocks, Journal of Geology, Vol. 64, No. 5, pp. 473-479. https://doi.org/10.1086/626379
  9. Maranini, E. and Brignoli, M.(1999), Creep Behaviour of a Weak Rock : Experimental Characterization, International Journal of Rock Mechanics and Mining Sciences, Vol. 36, No. 1, pp. 127-138. https://doi.org/10.1016/S0148-9062(98)00171-5
  10. Okubo, S., Nishimatsu, Y. and Fukui, K.(1991), Technical Note Complete Creep Curves under Uniaxial Compression, International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts, Vol. 28, No. 1, pp. 77-82. https://doi.org/10.1016/0148-9062(91)93235-X
  11. Overt, L.(1967), Rock Mechanics and the Design of Structures in Rock, John Wiley & Sons Inc., New York, pp. 293-301.
  12. Penny, R. K. and Marriott, D. L.(1995), Design for Creep, Chapman & Hall London SEI 8HN, UK, p. 426.
  13. Pfeifle, T. W., Senseny, P. E. and Mellegard, K. D.(1987), Influence of Variables on the Consolidation and Unconfined Compressive Strength of Crushed Salt, Report No. BMI/ ONWI-627.
  14. Robertson, E. C.(1964), Viscoelasticity of Rocks, In State of Stress in the Earth's Crust, W. R. Judd(Ed.), New York, Elsevier, pp. 1275-1314.
  15. Singh, D. P.(1975), A Study of Creep of Rocks, International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts, Vol. 12, No. 9, pp. 271-276. https://doi.org/10.1016/0148-9062(75)91084-0