한국지반공학회논문집 (Journal of the Korean Geotechnical Society)

  • 제30권1호
  • /
  • Pages.65-74
  • /
  • 2014
  • /
  • 1229-2427(pISSN)
  • /
  • 2288-646X(eISSN)
한국지반공학회 (Korean Geotechnical Society)
권호 표지
DOI QR코드

DOI QR Code

고결모래의 일축압축강도와 전단파속도의 상관관계

Relationship between Unconfined Compressive Strength and Shear Wave Velocity of Cemented Sands

  • 박성식 (경북대학교 공과대학 건축토목공학부 토목공학전공) ;
  • 황세훈 (경북대학교 공과대학 건축토목공학부 토목공학전공)
  • 투고 : 2013.10.13
  • 심사 : 2014.01.14
  • 발행 : 2014.01.31
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

시멘트 혼합토는 도로 및 댐 현장을 비롯하여 최근에는 연약지반 개량공법에도 자주 사용되고 있다. 시멘트 혼합토의 강도는 주로 현장에서 채취한 코어나 실험실에서 양생한 공시체를 이용하여 실내에서 일축압축시험이나 삼축압축시험을 통하여 측정되고 있다. 이와 같이 현장에서 시료를 채취하거나 실내에서 공시체를 양생하기 위해서는 상당한 비용과 시간이 소요된다. 하지만 때론 현장에서 빠르고 신속하게 지반의 고결 정도나 강도를 판단할 필요가 있다. 따라서 본 연구에서는 현장에서 고결된 지반의 강도 예측을 위한 기초연구로서 고결모래의 전단파속도와 일축압축강도의 상관관계를 연구하였다. 낙동강모래에 보통 포틀랜드 시멘트를 4, 8, 12, 16%로 혼합하여 다짐방법으로 직경 5cm, 높이 10cm의 소형 공시체 제작한 다음, 대기 중에서 7, 14, 28일 동안 양생하였다. 또한 최근 자원 재활용을 위해 자주 사용되고 있는 고로슬래그에 알칼리 활성화제인 수산화나트륨(NaOH)을 혼합하여 고결토를 제작하였다. 양생이 완료된 고결모래에 먼저 전단파속도시험을 실시한 다음 일축압축시험을 통하여 강도를 측정하였다. 고결모래의 시멘트비와 고로슬래그비가 증가할수록 공시체의 건조밀도가 증가하고 생성된 수화물로 인해 구조가 치밀해져 일축압축강도가 증가하면서 전단파속도 또한 증가하는 경향을 보였다. 고결제를 16% 이하로 혼합한 고결모래의 경우 전단파속도와 일축압축강도의 상관관계는 비선형적으로 증가하는 경향을 보였다.

Cemented soils have been widely used in road and dam construction, and recently ground improvement of soft soils. The strength of such cemented soils can be tested by using cored sample or laboratory-prepared specimen through unconfined compression or triaxial tests. It takes time to core a sample or prepare a testing specimen in the laboratory. In a certain situation, it is necessary to determine the in-situ strength of cemented soils very quickly and on time. In this study, the relation between unconfined compressive strength and shear wave velocity was investigated for predicting the in-situ strength of cemented soils. A small cemented specimen with 5 cm in diameter and 10 cm in height was prepared by Nakdong river sand and ordinary Portland cement. Its cement ratios were 4, 8, 12, and 16% and air cured for 7, 14, and 28 days. For recycling of resources, a blast furnace slag was also used with sodium hydroxide as an alkaline activator. The shear wave velocity for cemented soils was measured and then unconfined compressive strength test was carried out. As a cement ratio increased, the shear wave velocity and unconfined compressive strength increased due to increased density and denser structure. The relation between unconfined compressive strength and shear wave velocity increased nonlinearly for cemented soils with less than 16% of cement ratio.

키워드

참고문헌

  1. Amaral, M., Viana da Fonseca, A., Arroyo, M., Cascante, G., and Carvalho, J. M. (2011), "Compression and shear wave propagation in cementes-sand specimens", Geotechnique Letters (ICE Publication).
  2. Chan, C. M. and Ch'ng, S. S. (2010), "Preliminary Study of S-Wave Velocity and Unconfined Compressive Strength of Cement-Palf Stabilised Kaolin", International Journal of Intergrated Engineering, Vol. 2, No. 2, pp. 27-34.
  3. Cho, G. C. and Lee, I. M. (2002), "Soil Properties in Relation to Elastic Wave", Journal of the Korean Geotechnical Society, Vol.18, No.6, pp.83-101.
  4. Dyvik, R. and Madshus, C. (1985), "Laboratory Measurement of $G_{max}$ Using Bender Elements", Proceedings ASCE Annual Convention, Advances in the Art of Testing Soil Under Cyclic Conditions, Detroit, Michigan.
  5. Kim, H. S. (2011), Development and Applications of Piezo-electric Penetrartion Probe for In-Situ Measurement of Shear Wave Velocities Soft Clay, Ph.D. Thesis, Kyung Hee University.
  6. Kim, K. Y., Park, H. G., and Jeon, J. S. (2005), "Strength Characteristics of Cemented Sand and Gravel", Journal of the Korean Geotechnical Society, Vol.21, No.10, pp.61-71.
  7. Ladd, R. S. (1978), "Preparing test specimens using undercompaction", Geotechnical Testing Journal, Vol.1, No.1, pp.16-23. https://doi.org/10.1520/GTJ10364J
  8. Lee, J. S. and Lee, C. H. (2006), "Principles and Considerations of Bender Element Tests", Journal of the Korean Geotechnical Society, Vol.22, No.5, pp.47-57.
  9. Lee, C. H., Yoon, H. K., Lee, W. J., and Lee, J. S. (2008), "Elastic Wave Characteristics in Cemented Engineered Soils", Journal of the Korean Geotechnical Society, Vol.24, No.2, pp.87-97.
  10. Oh, S. H., Jung, J. W., Mok, Y. J., Park, D. S., and Park, C. S. (2008), "Correlation Undrained Shear Strength and Density of Silt with Shear Wave Velocity", Journal of the Korean Geotechnical Society, Vol.24, No.5, pp.79-87.
  11. Park, D. S. (2008), Relationship between Shear Modulus and Undrained Shear Strength of Normally Consolidated Silt, Ph.D. Thesis, Kyung Hee University.
  12. Park, S. S. and Choi, S. G. (2013), "A Study on Sand Cementation and its Early-Strength Using Blast Furnace Slag and Alkaline Activators", Journal of the Korean Geotechnical Society, Vol.29, No.4, pp.45-56. https://doi.org/10.7843/kgs.2013.29.4.45
  13. Park, S. S. and Hwang, S. H. (2012), "A Study on Durability Test of Cemented Soils", Journal of the Korean Geotechnical Society, Vol.28, No.11, pp.79-86. https://doi.org/10.7843/kgs.2012.28.11.79
  14. Park, S. S., Kim, K. Y., Choi, H. S., and Kim, C. W. (2009), "Effect of Different Curing Methods on the Unconfined Compressive Strength of Cemented Sand", Journal of the Korean Society of Civil Engineers, Vol.29, No.5C, pp.207-215.
  15. Park, S. S. and Lee, J. W. (2012), "Effect of Sea Water on Curing and Strength of Cemented Sand", Journal of the Korean Geotechnical Society, Vol.28, No.6, pp.71-79. https://doi.org/10.7843/kgs.2012.28.6.71
  16. Pineda, J. A., Arroyo, M., Romero, E., and Alonso, E. E. (2008), "Dynamic tracking of hydraulically induced clay stone degradation", Proceedings of the 4th International Symposium on Deformation Characteristics of Geomaterials IOS Press, pp.809-817.
  17. Shirley, D. J. and Hampton, L. D. (1978), "Shear wave measurements in laboratory sediments", J. Acoustical Society of America, Vol.63, No.2, pp.607-613. https://doi.org/10.1121/1.381760
  18. Suwal, L. P. and Kuwano, R. (2013), "Disk shaped piezo-ceramic transducer for P and S wave measurement in a laboratory soil specimen", Soils and Foundations, Vol.53, No.4, pp.510-524. https://doi.org/10.1016/j.sandf.2013.06.004
  19. Takahashi, H., Kitazume, M., Noguchi, T., and Suzuki, N. (2011), "Seismic-resistant effect of cement-treated soil for quay wall", Proceedings of the Institution of Civil Engineers- Ground Improvement, Vol.164, No.3.
  20. Tezcan, S. S., Ozdemir, Z., and Keceli, A. (2009), "Seismic technique to determine the allowable bearing pressure for shallow foundations in soils and rocks", Acta Geophysica, Vol.57, No.2, pp.1-14. https://doi.org/10.2478/s11600-008-0081-3
  21. Viggiani, G. and Atkinson, J. H. (1995), "Interpretation of bender element tests", Geotechnique, Vol.45, No.1, pp.149-154. https://doi.org/10.1680/geot.1995.45.1.149
  22. Yu, H. G. (2001), A Comparative Study of Compressive Strength of Concrete Concerned On Methods of Curing, Master's Thesis, Konkuk University.

피인용 문헌

  1. Effects of cement content and curing period on strength enhancement of cemented calcareous sand vol.39, pp.9, 2021, https://doi.org/10.1080/1064119x.2020.1804018
  2. Correlating failure strength with wave velocities for cemented sands from the particle-level analysis vol.152, pp.None, 2014, https://doi.org/10.1016/j.soildyn.2021.107062