Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
권호 표지
DOI QR코드

DOI QR Code

A Study on the Estimation of Compression Index in the East-Southern Coast Clay of Korea

동남해안 점토의 압축지수 추정에 관한 연구

  • Park, Choon-Sik (Dept. of Civil, Environment and Chemical Engrg., Changwon National Univ.) ;
  • Kim, Sung-Su (Musung Civil Engrg. and Construction)
  • 박춘식 (창원대학교 토목환경화공융합공학부) ;
  • 김성수 (무성토건)
  • Received : 2019.06.14
  • Accepted : 2019.07.26
  • Published : 2019.08.31
Download PDF
⟨ Previous Next ⟩

Abstract

This research has been conducted to suggest an estimation equation of compression index to be practically applied to the southeastern areas by finding out physical and mechanical characteristics of 229 points on the southeastern coast areas (Busan area: 78 points, Gimhae area: 103 points, Geoje area: 18 points, Changwon area: 30 points) through indoor tests and analyzing its relation to the compression index. From the results, we could not only find out correlation between natural water content, liquid limit and initial void ratio versus compression index for soft ground on each of the southeastern coast areas, but also an integrated correlation equation of the southeastern coast areas. In addition, we have performed a comparative analysis of the existing estimated equation of compression index and that found in this paper. As a result, the existing estimated equation suggested by foreign researchers has shown considerable error to be applied to the soft ground on the southeastern coast areas in Korea. The estimated equation of compression index with the water content out of the existing estimated equations has shown minimum 10.8% to maximum 48.1% of error rate, minimum 13.4% to maximum 288.5% of error rate with liquid limit or minimum 9.4% to maximum 211.4% of error rate with initial void ratio. On the other hand, error rates calculated with the estimated equations of compression index from this research have shown minimum 10.5% to maximum 13.4% with water content, minimum 11.6% to maximum 21.3 with liquid limit or minimum 7.1% to maximum 11.7% with initial void ratio, for better results than those with existing estimated equations. In addition, relation between compression index and expansion index has shown Cs = (1/5 ~ 1/12)Cc similar to the existing relation of Cs = (1/5 ~ 1/10)Cc.

본 논문은 동남해안 지역 229개소(부산지역 78개소, 김해지역 103개소, 거제지역 18개소, 창원지역 30개소)의 연약지반의 물리적, 역학적 특성을 실내실험을 통해 밝혀낸 후 압축지수와의 관계를 분석하여 실질적으로 동남해안 지역에 적용 가능한 압축지수 추정식을 제시하고자 수행하였다. 그 결과 동남해안 지역별로 연약지반의 자연함수비, 액성한계, 초기간극비와 압축지수의 상관관계를 밝혀낼 수 있었을 뿐만 아니라 동남해안 지역의 통합적인 상관식 또한 밝혀낼 수 있었다. 또한, 기존에 제시되어 있던 압축지수 추정식과 본 논문을 통해 밝혀진 추정식을 비교분석을 실시하였다. 그 결과 기존에 외국 학자들에 의해 제안된 압축지수 추정식은 한국의 동남해안 지역 연약지반에 적용하기에는 큰 오차율을 보였다. 기존에 제시된 추정식 중 함수비를 통한 압축지수 추정식에서는 최소 10.8%에서 최대 48.1%의 오차율이 나타났으며 액성한계를 통한 압축지수 추정식에서는 최소 13.4%에서 최대 288.5%, 초기간극비를 통한 압축지수 추정식에서는 최소 9.4%에서 최대 211.4%의 오차율이 나타났다. 반면 본 연구를 통해 산출된 압축지수 추정식을 통하여 오차율을 산정한 결과 함수비를 통한 추정식에서는 최소 10.5%에서 최대 13.4%, 액성한계를 통한 압축지수 추정식에서는 최소 11.6%에서 최대 21.3%, 초기간극비를 이용한 추정식에서는 최소 7.1%에서 최대 11.7%로 기존의 추정식보다 양질의 결과를 구할 수 있었다. 또한, 압축지수와 팽창지수의 관계는 Cs = (1/5 ~ 1/12)Cc로 기존에 제시된 Cs = (1/5 ~ 1/10)Cc와 비슷한 관계식을 형성하였다.

Keywords

References

  1. Azzouz, A. S., Krizek, R. J., and Corotis, R. B. (1976), "Regression Analysis of Soil Compressibility", Soils and Foundation, Japan Society of Soil Mechanics and Foundations Engineering, Tokyo, Japan.
  2. Casagrande, A. (1948), "Classification and Identification of Soils", Transaction, ASCE, Vol.113, pp.901-930.
  3. Choi, Y. J. (1986), "Experimental equations for estimating compression index Cc", Master's Thesis, Hanyang University (in Korean).
  4. Cozzolino, V. M. (1961), "Statical Forecasting of Compression Index", Proc., 5th Int. Conf. on Soil Mech and Found Engrg, Paris, France, Vol.1, pp.51-53.
  5. Gwon, H. J., Kim, D. S., Park, J. B., and Jeong, S. G. (2010), "Foundation engineering", Goomibook, Vol.2, pp.27-28.
  6. Herrero, O. R. (1983), "Universal Compression Index Equation", Closure, J. Geotech. Engrg, ASCE, Vol.109, No.5, pp.755-761. https://doi.org/10.1061/(ASCE)0733-9410(1983)109:5(755)
  7. Hong, S. J., Kim, D. H., Choi, Y. M., and Lee, W. J. (2011), "Prediction of Compression Index of Busan and Inchon Clays Considering Sedimentation State", Journal of Korean geotechnical society, Vol.27, No.9, pp.37-46 (in Korean). https://doi.org/10.7843/kgs.2011.27.9.037
  8. Hong, W. P. (1974), "The compressibility of soil accounting to varition of water content and soil density", Master's Thesis, Hanyang University (in Korean).
  9. Hough, B. K. (1957), "Basic Soils Engineering", The Ronard Press Company New York, pp.114-115.
  10. Jung, S. G., Gwak, J. M., Jang, W. Y., and Kim, D. G. (2000), "Compressibility Characteristics of Busan Clays", Journal of Korean Geotechnical Society, Vol 2000, pp.361-368 (in Korean).
  11. Kim, B. T., Kim, Y. S., and Bae, S. G. (2001), "Proposition Empirical Equations and Application of Artificial Neural Network to the Estimation of Compression Index", Journal of Korean Geotechnical Society, Vol.17, No.6, pp.25-36 (in Korean).
  12. Kim, D. H. (2002), "A Study on the Relationship between Physical Properties and Compression Index for Marine Clay", Doctor's Thesis, Kyunghee University (in Korean).
  13. Kim, S. H. (1998), "Determination of compression index using regression analysis and reliability analysis", Master's Thesis, Kyunghee University (in Korean).
  14. Koppula, S. D. (1981), "Statistical Estimation of Compression Index", Geotech. testing j, 4(2), pp.68-73. https://doi.org/10.1520/GTJ10768J
  15. Lim, C. W. (1982), "A study on the determination of coefficients of compression index equation for Korean saturated fine-giained soils", Master's Thesis, Seoul National University (in Korean).
  16. Lee, C. G. (1987), "Study on the computation of compression index of marine soft clays in Jeonnam region : Centering Skempton equation and regression equation", Master's Thesis, Joseon University (in Korean).
  17. Mayne, P. W. (1980), "Cam-clay Predictions of Undrained Strength", J. Geotech. Engrg. Div., ASCE, Vol.106, No.11, pp.1219-1242. https://doi.org/10.1061/AJGEB6.0001060
  18. Moran, Proctor, Mueser, and Rutledge, P. C. (1958), "Study of deep soil stabilization by vertical sand drains", Bureau of Yards and Docks, Department of the Navy, Washington, D. C.
  19. Nishida, Y. (1956), "A Brief Note on Compression Index of Soil", J. Soil Mech. and Found Eng, ASCE, Vol.82, No.3, pp.1-14.
  20. Schmertmann, J. H. (1955), "The Undisturbed Consolidation behavior of Clay", J. Soil Mech. and Found Eng, ASCE, 120, pp.1201-1233.
  21. Shin, E. C., Lee, G. J., and Shin, B. W. (1995), "Geotechnical Investigations of Soft Marine Clay in Incheon", Journal of the Korean Geotechnical Society, Vol.1995, No.1, pp.15-20 (in Korean).
  22. Skempton, A. W. (1944), "Note on Compressibility of Clays", Quarterly Journal of the Geotechnical Society of London, Vol.100, pp.119-135. https://doi.org/10.1144/GSL.JGS.1944.100.01-04.08
  23. Song, M. S. (1986), "Correlation of soil properties of marine clay in Korea", Master's Thesis, Hanyang University (in Korean).
  24. Sowers, G. B. (1970), "Introductory soil mechanics and foundations", The Macmillan Company, 3rd Ed., London, England..
  25. Terzaghi, K. (1923), "Die Berechnung Der Darchlassigkeitsziffer des Tones aus dem Verlauf der Hydrodynamicschen pannungserscheinungen, Akademic der Wissenchafton In Wein", Mathematisch-Naturwissenschaftlichs Klasse, Vol.132, pp.125-138 (in German).
  26. Terzaghi, K. and Peck R. (1967), "Soil Mechanics in Engineering Practice", John Wiley and Sons, Inc, New York N.Y.
  27. Yoo, N. H., Yoo, Y. T., and Park, S. B. (1988), "Studieds on the Engineering Characteristics of Alluvial Clayey Deposits in the Estuary Area of Seomjin River(1)", Journal of Korean Society of Geotechnical Engineering, Vol.4, No.1, pp.37-46 (in Korean).
  28. Yoon, G. L., Kim, B. T., and Jeon, S. S. (2004), "Empirical Correlations of Compression Index for Marine Clay from Regression Analysis", Canadian Geotechnical Journal, Vol.41(6), pp.1213-1221. https://doi.org/10.1139/t04-057