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A Program Development for Prediction of Negative Skin Friction on Piles by Consolidation Settlement

압밀침하를 고려한 말뚝의 부마찰력 예측 프로그램 개발

  • Kim, Hyeong-Joo (School of Civil and Environmental Engrg., Kunsan National Univ.) ;
  • Mission, Jose Leo C. (School of Civil and Environmental Engrg., Kunsan National Univ.)
  • Published : 2009.09.30

Abstract

The microcomputer program PileNSF (Pile Negative Skin Friction) is developed by the authors in a graphical user interface (GUI) environment using $MATLAB^{(R)}$ for predicting the bearing capacity of a pile embedded in a consolidating ground by surcharge loading. The proposed method extends the one-dimensional soil-pile model based on the nonlinear load transfer method in OpenSees to perform an advanced one-dimensional consolidation settlement analysis based on finite strain. The developed program has significant features of incorporating Mikasa's finite strain consolidation theory that accounts for reduction in the thickness of the clay layer as well as the change of the soil-pile interface length during the progress of consolidation. In addition, the consolidating situation of the ground by surcharge filling after the time of pile installation can also be considered in the analysis. The program analysis by the presented method has been verified and validated with several case studies of long-term test on single piles subjected to negative skin friction. Predicted results of negative skin friction (downdrag and dragload) as a result of long from consolidation settlement are shown to be in good agreement with measured and observed case data.

재하 하중에 의해 압밀 되는 지반에 관입 된 말뚝의 지지력을 예측하고자 MATLAB을 이용한 GUI환경에서 Pile NSF(Pile Negative Skin Friction)프로그램이 개발되었다. 본 연구에서 제안된 방법은 일차원 유한변위 압밀이론이 적용될 수 있도록 비선형 하중 전이법에 의한 일차원 토질-말뚝 모델 프로그램인 OpenSees 를 확장하였다. 개발된 프로그램은 압밀과정 중에 발생하는 토질-말뚝의 경계면 변화는 물론 유한 점토층의 저감이 고려되는 Mikasa의 유한변위이론을 융합하는 특성을 가지고 있다. 더 나아가 말뚝 타설 후에 재하성토에 의해 발생하는 지반의 압밀상태도 해석시에 고려할 수 있는 특징을 지니고 있다. 본 연구에서 제안된 방법에 의한 프로그램 해석은 부마찰력이 발생하는 말뚝에 대하여 말뚝 장기시험 사례 결과와 비교하여 타당성이 검증되었고, 압밀침하를 반영한 말뚝의 부마찰력 예측치는 측정된 결과와 잘 일치하고 있음을 보여주고 있다.

Keywords

References

  1. Alonso, E.E., Josa, A., and Ledesma, A. (1984), "Negative skin friction on piles: a simplified analysis and prediction procedure", Geotechnique, Vol.34, pp.341-357 https://doi.org/10.1680/geot.1984.34.3.341
  2. Boulanger, R. W. (2003a), The TzSimple1 Material. (http://opensees. berkeley.edu/)
  3. Boulanger, R. W. (2003b), The QzSimple1 Material. (http://opensees. berkeley.edu/)
  4. Bjerrum, L., Johannessen, I. J., and Eide, O. (1969), Reduction of negative skin friction on steel piles to rock. Proceedings 7th International Conference on Soil Mechanics and Foundation Engineering, Mexico City, August 25-29, Vol.2, pp.27-34
  5. Comodromos, E. and Bareka, S. (2005), "Evaluation of negative skin friction effects in pile foundations using 3D nonlinear analysis", Computers and Geotechnics, Vol.32, No.3, pp.210-221 https://doi.org/10.1016/j.compgeo.2005.01.006
  6. Fellenius, B.H. (2006), Results from long-term measurement in piles of drag load and downdrag", Canadian Geotechnical Journal, Vol.43, pp.409-430 https://doi.org/10.1139/t06-009
  7. Fellenius, B.H. (2008), "Effective stress analysis and set-up for shaft capacity of piles in clay", Honoring John Schmertmann "From research to practice in geotechnical engineering", The Geo-Institute of the American Society of Civil Engineers, ASCE Geotechnical Special Publications, GSP 180, pp.384-406
  8. Fukuya, T., Todoroki, T., and Kasuga, M. (1982), "Reduction of negative skin friction with steel tube NF pile", Proc., 7th Southeast Asian Geotechnical Conference, Hongkong, Vol.1, pp.333-347
  9. Indraratna, B., Balasubramaniam, A.S., Phamvan, P., and Wong, Y.K. (1992), "Development of negative skin friction on driven piles in soft Bangkok clay", Canadian Geotechnical Journal, Vol.29, No.3, pp.393-404 https://doi.org/10.1139/t92-044
  10. Jeong, S., Kim, S., and Briaud, J.L. (1997), "Analysis of downdrag on pile groups by the finite element method", Computers and Geotechnics, Vol.21, No.2, pp.143-161 https://doi.org/10.1016/S0266-352X(97)00018-9
  11. Kim, H.J. and Mission, J.L. (2009), "Negative skin friction on piles based on finite strain consolidation theory and nonlinear load transfer method", Korean Society of Civil Engineers (KSCE) Journal of Civil Engineering, Vol.13, No.2, pp.107-115
  12. Kulhawy, F.H. (1984), "Limiting tip and side resistance, Proc., Symp. On Design and Analysis of Pile Found., ASCE, New York, N.Y., pp.80-98
  13. Mazzoni, S., McKenna, F., Scott, M.H. et al. (2006), OpenSees Command Language Manual. http://opensees.berkeley.edu/
  14. Mikasa, M. (1965), "The Consolidation of Soft Clay – A New Consolidation Theory and Its Application", JSCE Prize Paper for 1964, Japan Society of Civil Engineers, pp.21-26
  15. Mosher, R.L. (1984), "Load Transfer Criteria for Numerical Analysis of Axially Loaded Piles in Sand - Part 1: Load-Transfer Criteria", Technical Report K-84-1, US Army Engineering Waterways Experimental Station, Mississippi
  16. OpenSees (2000), Open System for Earthquake Engineering Simulation, Pacific Earthquake Engineering Research Center, University of California, Berkeley, California. (http://opensees.berkeley.edu/)
  17. Poulos, H.G. and Davis, E.H. (1980), Pile Foundation Analysis and Design, John Wiley & Sons, Inc., pp.265-290
  18. Reese, L.C. and O'Neill, M.W. (1987), "Drilled Shafts: Construction Procedures and Design Methods", Report No. FHWA-HI-88-042, US Department of Transportation, Federal Highway Administration, Virginia
  19. Terzaghi, K. (1943), Theoretical Soil Mechanics, John Wiley and Sons, New York
  20. Tomlinson, M.J. (1986), Foundation Design and Construction, 5th Ed., Pitman Books Ltd., London, England
  21. Verruijt, A. (1995), Theory and Applications of Transport in Porous Media (Vol. 7) - Computational Geomechanics, Kluwer Academic Publishers, The Netherlands
  22. Vijayvergiya, V.N. (1977), "Load-movement characteristics of piles", Proceedings, Ports 77, American Society of Civil Engineers, Vol.11, pp.269-286
  23. Walker, L.K., Le, P., and Darvall, L. (1973), "Dragdown on coated and uncoated piles", Proc. 8th International Conference on Soil Mechanics and Foundation Engineering, ICSMFE, August, Vol.2, Paper 3/41, pp.257-262
  24. Wong, K.S., and Teh, C.I. (1995), "Negative Skin Friction on Piles in Layered Soil Deposit", Journal of Geotechnical and Geoenvironmental Engineering, American Society of Civil Engineers, Vol.121, No.6, pp.457-465 https://doi.org/10.1061/(ASCE)0733-9410(1995)121:6(457)