Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Determination of Undrained Shear Strength In Clay from Cone Pressuremeter Test

Cone Pressuremeter를 이용한 점성토의 전단 강도 산정

  • Published : 2004.10.01
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Abstract

The cone pressuremeter test (CPM) is a new in-situ test which combines a standard cone penetration test with a pressuremeter. The cone pressuremeter tests in clay are presented and analyzed. An analytical solution of CPM incorporated non-linear soil behavior with no volume change is presented, and curve fitting technique is proposed to make use of both the loading and unloading portions of the pressuremeter test. The proposed method is accomplished by putting greater emphasis on the unloading portion. Twenty CPM tests are analyzed using the proposed method, and the derived undrained shear strength of soil is compared with other tests such as field vane tests and laboratory tests. The interpreted soil parameters had resonable values when compared to other in-situ and laboratory test results. The cone pressuremeter has provided reliable measures of undrained shear strength using curve fitting method.

콘프레셔미터는 피에조콘 시험과 프레셔미터 시험을 동시에 수행할 수 있는 현장시험기로서 본 연구에서는 국내 점토지반에서 수행한 시험결과를 해석적으로 분석하였다. 콘프레셔미터 결과에 대한 이론적인 해는 흙이 비선형 거동을 하는 경우와 전단변형 중 체적변화가 발생하지 않는 경우에 대하여 해석적인 해가 존재한다. 이러한 해석적인 해로부터 콘프레셔미터의 결과중 하중 재하구간과 제하구간에 대해 Curve Fitting 방법을 사용한 콘프레셔미터 결과의 해석 방법을 제안하였다. 20개소의 현장에서 수행한 콘프레셔미터 결과 중 지반교란의 영향을 적게 받는 제하구간에 대하여 Curve Fitting 방법을 적용하여 점성토의 비배수 전단특성을 구하였다. 이렇게 구한 지반의 비배수 전단강도와 현장 Vane, 일축압축, 삼축압축 시험결과로부터 구한 지반의 비배수 전단강도를 서로 비교하여 콘프레셔미터 시험 결과로부터 Curve Fitting 방법을 통한 점성토 지반의 전단강도 특성파악의 적정성에 대해 평가하였다.

Keywords

References

  1. Anderson, W. F., and Pyrah, I. C. (1986), 'Undrained strength and deformation parameters from pressuremeter test results', The Pressuremeter and Its Marine Applications. Second International Symposium, pp.324-338
  2. Arman, A., Poplin, J. K. and Ahmad. (1975), 'Stuty of Vane Shear', Proc. Conf. In-Situ measure. Soil Prop., ASCE, Vol.1, pp.93-120
  3. Clough, G. W., Briaud, J. L, and Hughes, J. M. O. (1990), 'The development of pressuremeter testing', Proceedings of the Third International Symposium on Pressruemeter, Oxford, pp.25-45
  4. Ferreira, R. S., and Robertson, P. K. (1991), 'Interpretation of Undrained self-boring pressuremeter test results incorporating unloading', Canadian Geotechnical Journal, October
  5. Gibson, R. E., and Anderson, W. F. (1961), 'In situ measurement of soil properties with the pressuremeter', Civil Engineering and Public Works Review, 56, pp.615-618
  6. Houlsby, G. T., and Withers, N. J. (1988), 'Analysis of the cone pressuremeter test in clay', Geotechnique, 38, No.4, pp.575-587 https://doi.org/10.1680/geot.1988.38.4.575
  7. Hughes, J. M. O., and Robertson, P. K. (1985), 'Full displacement pressuremeter testing in sands', Canadian Geotechnical Journal, 22, No.3, pp.298-307 https://doi.org/10.1139/t85-043
  8. Jefferies, M. G. (1988), 'Determination of horizontal geostatic stress in clay with self-bored pressuremeter', Canadian Geotechnical Journal, 25, pp.559-573 https://doi.org/10.1139/t88-061
  9. Schnaid, F., and Houlsby, G. T. (1990), 'Calibration chamber tests of the cone pressuremeter in sand', Proceedings of the Third International Symposium on Pressruemeter, Oxford, pp.263-272
  10. Teh, C. I. (1987), An analytical study of the cone penetration test, Ph.D thesis, University of Oxford
  11. Timoshenko, S. P., and Goodier, J. N. (1934), Theory of Elasticity, New York, McGraw-Hill
  12. Vesic, A. S. (1963), 'Bearing Capacity of deep foundations on sand', Stresses in soils and layered systems, Canadian Highway Research Board, Report 39
  13. Williams, D. J. (1986), 'Evaluation of different soil tests for determining design parameters', Interpretation of Field Testing for Design Parameters, Adelaide, pp.174-179
  14. Withers, N. J., Schaap, L. H. J., and Dalton, J. C. P. (1986), 'The development of the full displacement pressuremeter', Proc. 2nd Int. Symp. The Pressuremeter and Its Marine Applications. ASTM Special Technical Publication 950, pp.38-56
  15. Wroth, C. P. (1984), 'The interpretation of in situ soil tests', Geotechnique, 34, pp.449-489 https://doi.org/10.1680/geot.1984.34.4.449