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Characteristics of Shear Behavior of Remolded Nak-dong River Sandy Silt

재성형된 낙동강 모래질 실트의 전단거동 특성

  • Kim Young-Su (Dept. of Civil Engrg., Kyungpook National Univ.) ;
  • Tint Khin Swe (Dept. of Civil Engrg., Kyungpook National Univ.) ;
  • Kim Dae-Man (Dept. of Civil Engrg., Jinju National Univ.)
  • Published : 2007.03.31

Abstract

The results from normally consolidated isotropic drained and undrained triaxial compression tests (NCIU and NCID) on sand with high silt content were presented in this paper. The experiments were performed on specimens of Nak-dong River sand with 63% silt content under effective confined pressures, 100 kPa to 400 kPa. From test results, Sandy silt became initially compressive but eventually appeared to provide dilatancy response throughout the entire stress-strain curve The behavior of sandy silt was more difficult to characterize than that of clay and sand due to lower plastic characteristic. Especially, the samples exhibited dilatancy development during shear after failure. The shear behavior and shear strength parameters of sandy silt can be determined as stress-strain behaviors are described by the Mohr-Coulomb failure criterion. The shear behaviors were observed increasing dilatancy volume change tendency with strain-softening tendency after failure. In this paper, the behavior of dilatancy depends on not only sand content but also fine content with low-cohesion during shear in the samples of sandy silt.

본 논문에서는 실트 함유율이 높은 모래에 대한 정규압밀 등방배수 및 비배수 삼축압축시험(NCIU 및 NCID) 결과를 나타내었다. 유효구속응력 $100\sim400kpa$하에서 실트 함유율이 63%인 낙동강 모래 시료를 사용하여 실험을 실시하였다. 실험결과, 모래질 실트는 초기에는 압축이 되지만 전체적인 응력-변형률 곡선에서 최종적으로 체적팽창반응을 보였다. 모래질 실트의 거동은 낮은 소성 특성으로 인하여 점토와 모래보다 비하여 그 특성을 묘사하기가 어려웠다. 특히, 시료는 파괴 후 전단과정에서 팽창현상을 보였다. 모래질 실트의 전단거동과 전단강도정수는 응력-변형률 거동과 Mohr-Coulomb 파괴규준에 의하여 결정되는데, 전단거동은 파괴 후 변형률 연화 경향과 같이 체적변화가 증가하는 것으로 관찰되었다. 본 논문에서 모래질 실트의 전단과정 동안에 발생되는 팽창거동은 모래 함유율 뿐만 아니라 저점착력을 가진 세립자의 함유율에 의해서도 달라졌다.

Keywords

References

  1. Anandarajah, A. (2000), 'Triaxial behavior of kaolinite in different pore fluids', J. Geotech. Eng., ASCE, Vol.126, No.2, pp.148-156 https://doi.org/10.1061/(ASCE)1090-0241(2000)126:2(148)
  2. Been Ken and Jefferies Michael (2004), 'Stress-dilatancy in very loose sand', Can. Geotech. J., Vol.41, pp.972-989 https://doi.org/10.1139/t04-038
  3. Boukpeti, N. (2000), 'Triaxial behavior of refined Superior sand model', Computer and Geotechnics. J., Vol.26, pp.65-81 https://doi.org/10.1016/S0266-352X(99)00030-0
  4. Brandon Thomas L., Rose Andrew T. (2006), 'Drained and undrained strength interpretation for low-Plasticity silts', J. Geotech. Engrg, ASCE, Vol.132, No.2, pp.250-257
  5. Fleming Lorraine N. (1990), 'Stress-deformation characteristics of Alaskan silt', J. Geotech. Eng., ASCE, Vol.116, No.3, pp.377-393 https://doi.org/10.1061/(ASCE)0733-9410(1990)116:3(377)
  6. Horpibulsuk Suksun (2004), 'Undrained shear behavior of cement admixed clay at high water content', Vol.130, No.10, pp.1096-1105 https://doi.org/10.1061/(ASCE)1090-0241(2004)130:10(1096)
  7. Lee Junhwan, Salgado Rodrigo (2004) 'Stiffness degradation and shear strength of silty sands', Can. Geotech. J., Vol.4, pp.831-843
  8. Lo S.R. and Wardani S.P.R. (2002) 'Strength and dilatancy of a silt stabilization by a cement and fly ash mixture', Can. Geotech. J., Vol.39, pp.77-89 https://doi.org/10.1139/t01-062
  9. Pestana Juan M. (2002), 'Evaluation of a constitutive model for clays and sands : Part I-sand behavior', Int. J. Numer. Anal. Meth. Geomech., Vol.26, pp.1097-1121 https://doi.org/10.1002/nag.237
  10. Rahardjo, H. (2004), 'Shear strength of a compacted residual soil from consolidated drained and constant water content triaxial tests', Can. Geotech. J., Vol.41, ppA2l-435
  11. Salgado, R. (2000), 'Shear strength and stiffuess of silty sand', J. Geotech. Eng., ASCE, Vol.126, No.5, pp.451-462 https://doi.org/10.1061/(ASCE)1090-0241(2000)126:5(451)
  12. Shapiro Saul (2003) 'Effect of silt on three-dimensional stress-strain behavior of loose sand', J.Geotech. Engrg., ASCE, Vol.129, No.1, pp.1-11
  13. Yamamuro Jerry A., Kelly M. Covert (2001), 'Monotonic and cyclic liquefaction of very loose sands with high silt content', J. Geotech. Eng., ASCE, Vol.127, No.4, pp.314-324 https://doi.org/10.1061/(ASCE)1090-0241(2001)127:4(314)
  14. Yamamuro Jerry A. and Lade Pow V. (1998), 'Steady-state concepts and static liquefaction of silty sands', J.Geotech. Engrg., ASCE, Vol.124, No.9, pp.868-877 https://doi.org/10.1061/(ASCE)1090-0241(1998)124:9(868)
  15. Yamamuro Jerry A., Wood Fletcher M. (2004), 'Effect of depositional method on the undrained behavior and microstructure of sand with silt', Soil dynamics and Earthquake Eng., Vol.24. pp.751-760 https://doi.org/10.1016/j.soildyn.2004.06.004
  16. Yilmaz, M.T. (2004), 'Undrained cyclic shear and deformation behavior of silt-clay mixtures of Adapazari, Turkey', Soil dynamics and Earthquake Eng., Vol.24, pp.497-507 https://doi.org/10.1016/j.soildyn.2004.04.002
  17. Young-Su Kim, Dae-Man Kim (2004), 'Characteristics of Undrained static Shear Behavior for Sand Due to againg effect', J. Geotech. Eng., KGS, Vol.20, No.6, pp.137-150