한국지반공학회논문집 (Journal of the Korean Geotechnical Society)

  • 제27권1호
  • /
  • Pages.41-52
  • /
  • 2011
  • /
  • 1229-2427(pISSN)
  • /
  • 2288-646X(eISSN)
한국지반공학회 (Korean Geotechnical Society)
권호 표지
DOI QR코드

DOI QR Code

다짐 풍화토의 K0 압축 삼축시험에서 나타난 파괴이전 흡수응력 특성곡선

Suction Stress Characteristic Curve before Failure in the K0 Consolidated Triaxial Tests for the Compacted Residual Soil

  • 투고 : 2010.07.07
  • 심사 : 2010.11.04
  • 발행 : 2011.01.31
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

풍화토의 다짐성형 시료에 대한 삼축시험의 $K_0$ 압밀 결과를 바탕으로 불포화토에 대한 유효응력 가설을 검증하였다. 흡수응력 특성곡선은 함수특성에 관한 불포화토 거동을 기술하며, 전단강도나 함수특성곡선으로부터 구할 수 있다. 본 연구에서는 K0 압밀 경로도 흡수응력 특성곡선을 정의할 수 있음을 밝혔다. 그리고 흡수응력에 근거하여 유효응력을 정의할 수 있었다. 다양한 모관흡수력 하에서 $K_0$ 경로는 유효응력에 의하여 유일한 직선으로 기술될 수 있었다. 또한 측정된 $K_0$ 값은 유효응력에 의하여 임의의 모관흡수력에 대하여 일정한 값으로 분석되었다. $K_0$ 압밀경로로부터 구한 흡수응력 특성곡선은 파괴규준으로부터 구한 것과 일치한다. 특히 함수특성곡선으로부터 구한 흡수응력 특성곡선이 $K_0$ 압밀 경로 및 파괴시 응력에서 나타나는 유효응력 거동을 모두 일관되게 기술할 수 있었다. 흡수응력 특성곡선에 기반한 유효응력은 압밀에서 파괴에 이르는 불포화토의 전 거동을 기술할 수 있다.

The hypothesis on effective stress of unsaturated soil is validated by $K_0$ consolidation results of triaxial tests for the compacted residual soil. The stress characteristic curve (SSCC) can describe unsaturated soil behavior on water contents, which was defined from shear strength or from soil water characteristic curves. In this study, it was found that the stress path of $K_0$ consolidation can also define the SSCC. The effective stress was defined by SSCC. $K_0$ paths for various matric suctions could be described as a unique line by effective stress. The measured values of $K_0$ were interpreted by effective stress as a constant with respect to matric suction. Since the SSCC from $K_0$ consolidation agrees with that from the shear strength, the SSCC from soil water retention curve could describe effective stress behavior consistently on both $K_0$ consolidation path and stress at failure. The effective stress based on SSCC can describe the entire unsaturated behavior from consolidation to failure.

키워드

참고문헌

  1. 오세붕, 김태경 (2008), "낮은 모관흡수력 수준에서 불포화토의 Bishop 응력에 관한 연구", 한국지반공학회논문집, 제24권 5호.
  2. Bishop, A. W. (1954), "The use of pore water coefficients in practice", Geotechnique, 4(4), 148-152. https://doi.org/10.1680/geot.1954.4.4.148
  3. Bishop, A. W. (1959), "The principle of effective stress", Teknisk Ukeblad I Samarbeide Med Teknikk, Oslo, Norway, 106(39), 859-863.
  4. Bishop, A. W., and Blight, G. E. (1963), "Some aspects of effective stress in saturated and unsaturated soils", Geotechnique, 13, 177-197. https://doi.org/10.1680/geot.1963.13.3.177
  5. Fredlund, D. G., and Morgenstern, N. R. (1977), "Stress state variables for unsaturated soils", J. Envir. Engrg. Div., 103(5), 447-466.
  6. Gallipoli, D., Gens, A., Sharma, A. and Vaunat, J. (2003), "An elasto-plastic model for unsaturated soil incorporating the effects of suction and degree of saturation on mechanical behavior", Geotechnique, 53(1), 123-135. https://doi.org/10.1680/geot.2003.53.1.123
  7. Jennings, J. E. B., and Burland, J. B. (1962), "Limitation to the use of effective stresses in unsaturated soils", Geotechnique, 12, 125-144. https://doi.org/10.1680/geot.1962.12.2.125
  8. Khalili, N., and Khabbaz, M. H. (1998), "A unique relationship for X for the determination of shear strength of unsaturated soils", Geotechnique, 48(5), 681-688. https://doi.org/10.1680/geot.1998.48.5.681
  9. Khalili, N., Geiser, F., and Blight, G. E. (2004), "Effective stress in unsaturated soils: Review with new evidence", Int. J. Geomech., 4(2), 115-126. https://doi.org/10.1061/(ASCE)1532-3641(2004)4:2(115)
  10. Lu, N. (2008), "Is matric suction stress variable?" Journal of Geotechnical and Geoenvironmental Engineering, 134(7), 899-905. https://doi.org/10.1061/(ASCE)1090-0241(2008)134:7(899)
  11. Lu, N., and Godt, J., and Wu, D. T. (2010), "A closed-form equation for effective stress in unsaturated soil", Water Resources Research, doi:10.1029/2009WR008646, in press
  12. Lu, N., and Likos, W. J. (2004), Unsaturated Soil Mechanics, Wiley, New York.
  13. Lu, N., and Likos, W. J. (2006), "Suction stress characteristic curve for unsaturated soils", Journal of Geotechnical and Geoenvironmental Engineering, 132(2), 131-142. https://doi.org/10.1061/(ASCE)1090-0241(2006)132:2(131)
  14. Oh, S., Lu, N., Y. K. Kim, S. J. Lee, and S. R. Lee (2010), "Relation between the Soil Water Characteristic Curve and the Suction Stress Characteristic Curve: Experimental Evidence from Tests on Residual Soils", Journal of Geotechnical and Geoenvironmental Engineering, submitted.
  15. Vanapilli S. K. Fredlund D. G., Pufahl D. E., and Clifton A. W. (1996), "Model for the prediction of shear strength with respect to soil suction", Canadian Geotechnical Journal, Vol.33, pp.379-392. https://doi.org/10.1139/t96-060
  16. van Genuchten, M. T. (1980), "A closed-form equation for predicting the hydraulic conductivity of unsaturated soils", Soil Science Society of America Journal, 44, 892-898. https://doi.org/10.2136/sssaj1980.03615995004400050002x
  17. van Genuchten, M. T., Leij, F. J., and Yates, S. R. (1991), The RETC Code for Quantifying the Hydraulic Functions of Unsaturated Soils, EPA 600/2-91/065.

피인용 문헌

  1. 다짐된 불포화 실트질 모래의 흡수응력과 일축압축강도 vol.27, pp.8, 2011, https://doi.org/10.7843/kgs.2011.27.8.031
  2. 구속응력에 따른 함수특성곡선이 변포화토의 유효응력에 미치는 효과 vol.32, pp.c4, 2011, https://doi.org/10.12652/ksce.2012.32.4c.169