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A Study on Determination of Piezocone Coefficients of Soft Clay Ground

연약지반의 피에조콘계수 결정에 관한 연구

  • Ahn, Taebong (Department of Railroad and Civil Engineering, Woosong University)
  • Received : 2021.06.30
  • Accepted : 2021.08.19
  • Published : 2021.09.01

Abstract

In this study, piezocone coefficients of clays (Hwasung, Gunsan, Changwon, Busan) were analyzed from piezocone penetration tests those accompanied with vane shear and UU tests. Piezocone coefficients of west sea clays (Hwasung, Gunsan), i.e, Nkt is 12.6 and Nqu is 8.8, while those of south sea clays are 16.5 and 9.2 respectively. The difference of liquid limit between south and west clays causes main roles those which west sea clay is generally lower than 50%, i.e, CL, and liquid limit of south sea clay is mostly higher than 50%, i.e CH. Piezocone coefficients obtained from several tests show similar trends even though they still have some differences depending on each test. However, they show clear differences depending on liquid limit. Therefore, piezocone coefficients need to be used with caution depending on LL.

본 연구에서는 현장베인시험과 UU시험과 함께 수행한 피에조콘 관입시험결과를 이용하여 화성, 군산, 창원, 부산지역 점토의 피에조콘계수를 분석하였다. 서해안(화성, 군산) 지역의 피에조콘계수는 Nkt=12.6, Nqu =8.8이며 남해안(창원, 부산) 지역의 Nkt=16.5, Nqu =9.2이다. 이것은 지역별로 흙의 물리적 특성의 차이에 의한 것이며, 서해안 지역은 액성한계가 50% 이하인 CL이 대다수 분포하고, 남해안 지역은 액성한계가 50% 이상인 CH가 대다수 분포한다. 시험별 및 액성한계별 피에조콘계수 분류결과, 시험별로 약간의 차이를 보이나 기존에 제시된 값과 유사한 경향을 보인다. 그러나 흙의 물리적 특성인 액성한계에 따른 피에조콘계수 차이는 확연히 나타난다. 피에조콘계수는 액성한계와 밀접한 관련이 있으며 액성한계에 따른 선별 적용이 필요하다.

Keywords

References

  1. Campanella, R. G., Gillespie, D. and Robertson, P. K. (1982), Pore pressure during cone penetration testing, Proceeding of the 2nd European Symposium on penetration Testing, ESOPT-II, Amsterdam, 2, pp. 507~512.
  2. Chen, B. S. and Mayne, P. W. (1993), Piezocone evaluation of underained shear strength in clays, Proceedings of 11th Southeast Asian Geotechnical Conference, Singapore, pp. 91~98.
  3. Karlsrud, K., Lunne, T. and Brattlieu, K. (1996), Improved CPTU Correlations Based on Block Samples, Nordisk Geoteknikermote, Reykjavik.
  4. Kim, J. K. Sung, K. K. Kim, H. J. and Kim, Y. W. (2000), The application of piezocone penetration test at Inchon International Airport, Journal of Korean Geotechnical Society, Vol. 16, No. 2, pp. 115~123 (In Korean).
  5. Kjekstad, O., Lunne, T. and Clausen, C. J. F. (1978), Comparison Between insitu cone resisrance and laboratory strength for overconsolidated north sea clays, Marine Geotechnology, Vol. 3, No. 4.
  6. Lee, S. J. (1997), Estimations of geotechnical properties from piezocone penetration tests in south Korea, Ph.D Thesis, Seoul National University (In Korean).
  7. Lunne, T., Eide, O. and De Ruiter, J. (1976), Correlation between cone resistance and vane shear strength in some Scandinavian soft to medium stiff clays, Canadian Geotechnical Journal, Vol. 13, pp. 430~441. https://doi.org/10.1139/t76-043
  8. Lunne, T. and Kleven, A. (1981), Role OF CPT in north sea foundation engineering, Session at the ASCE National Convention Cone Penetration Testing and Materials, ASCE, St.Louis, pp. 76~107.
  9. Lunne, T., Robertson, P. K. and Powell, J. J. M. (1997), Cone Penetration Testing, E&FN SPON, London, UK.
  10. Robertson, P. K., Campanella, R. G., Gillespie, D. and Greig, J. (1986), Use of piezometer cone data, Proc. ASCE Specialty Conf. In Situ 86, Blacksberg, pp. 1263~1280.
  11. Robertson, P. K. and Campanella, R. G. (1983), Interpretation of Cone Penetration Tests: Sands, Canadian Geotechnical Journal, Vol. 20, No. 4, pp. 719~733.
  12. Schmertmann, J. H. (1978), Guidelines for Cone Penetration Test Performance and Design, Federal Highway Administration, Report FHWA-TS-78-208, Washington, July.
  13. Senneset, K., Janbu, N. and Svano, G. (1982), Strength and deformation parameters from cone penetrations tests, Proceedings of the 2nd European Symposium on Penetration Testing, ESOPT-II, Amsterdam, 2, Balkema Pub., Rotterdam, pp. 863~870.
  14. Tanaka, H. (1995), National report-the current sate of CPT in Japan, Proc. Int. Sym. on Cone Penetration Testing CPT95, Linkoping, Sweden, pp. 115~124.
  15. Teh, C. I. and Houlsby, G. T. (1991), An analytical study of the cone penetration test in clay, Geotechnique, No. 41, Vol. 1, pp. 17~34.
  16. Vesic, A. S. (1972), Expanstion of cavities in infinite soil masses, Journal of the Soil Mechanics and Foundation Division, ASCE, Vol. 98, SM3, pp. 265~290. https://doi.org/10.1061/JSFEAQ.0001740