Beam on Nonlinear Winkler Foundation and Modified Neutral Plane Solution for Calculating Downdrag Settlement
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 139, Issue 9
Abstract
The neutral plane solution has been widely used to estimate downdrag settlements and drag loads mobilized in piles in consolidating soil profiles. Pile settlement is typically assumed equal to soil settlement at the neutral plane depth corresponding to effective stress conditions at the end of consolidation. This paper demonstrates that, in general, pile settlement is not equal to soil settlement at the neutral plane depth; rather, it is the relative velocity between the pile and soil that is zero at the neutral plane depth. A beam on nonlinear Winkler foundation (BNWF) solution, in which the shaft friction capacity is proportional to effective stress, is utilized to demonstrate that pile settlement is not equal to soil settlement at the neutral plane depth, because the neutral plane depth evolves as consolidation progresses. The BNWF solution also shows that pile settlement depends on drainage conditions, with more settlement occurring when consolidation occurs first near the top of the consolidating soil layer, and less settlement occurring when consolidation initiates at the bottom. A modified neutral plane solution that is amenable to hand calculation is formulated to account for the evolution of neutral plane depth on pile settlement. Finally, the proposed BNWF and modified neutral plane solutions are compared with measurements of downdrag settlement from a centrifuge test program. The proposed methods produced more accurate estimates of pile settlement than the traditional neutral plane solution.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The authors thank the research group at Hong Kong University of Science and Technology for having performed high-quality centrifuge tests and for publishing the data that was directly relevant to this paper. The authors also thank the National Natural Science Foundation of China (No. 51079074 and No. 51038007) and the Chinese Scholarship Council for providing the funding that enabled Rui Wang to visit the University of California, Los Angeles, to do the work presented in this paper. This material is based upon research performed in a renovated collaboratory by the National Science Foundation under Grant No. 0963183, which is an award funded under the American Recovery and Reinvestment Act of 2009 (ARRA).
References
Bjerrum, L., Johannessen, I. J., and Eide, O. (1969). “Reduction of negative skin friction on steel piles to rock.” Proc., 7th Int. Conf. on Soil Mechanics and Foundation Engineering, Vol. 2, Sociedad Mexicana de Mecanica, Mexico City, 27–34.
Boulanger, R. W., and Brandenberg, S. J. (2004). “Neutral plane solution for liquefaction-induced downdrag on vertical piles.” Proc., ASCE Geo-Trans Conf., GSP 126, ASCE, Reston, VA. 27–31.
Boulanger, R. W., Kutter, B. L., Brandenberg, S. J., Singh, P., and Chang, D. (2003). “Pile foundations in liquefied and laterally spreading ground during earthquakes: Centrifuge experiments and analyses.” Rep. No. UCD/CGM-03/01, Center for Geotechnical Modeling, Dept. of Civil Engineering, Univ. of California, Davis, CA.
Endo, M., Minou, A., Kawasaki, T., and Shibata, T. (1969). “Negative skin friction acting on steel piles in clay.” Proc., 8th Int. Conf. on Soil Mechanics and Foundation Engineering, Vol. 2, 85–92.
Esmail, H. (1996). “Neutral plane of single piles in clay subjected to surcharge loading.” M.S. thesis, Concordia Univ., Montréal.
Fellenius, B. H. (1972). “Downdrag on long piles in clay due to negative skin friction.” Can. Geotech. J., 9(4), 323–337.
Fellenius, B. H. (1984). “Negative skin friction and settlement of piles.” Proc., Second Int. Seminar, Pile Foundations, Nanyang Technological Institute, Singapore, 1–12.
Hanna, A. M., and Sharif, A. (2006). “Drag force on single piles in clay subjected to surcharge loading.” Int. J. Geomech., 6(2), 89–96.
Holtz, R. D., Kovacs, W. D., and Sheahan, T. C. (2011). An introduction to geotechnical engineering, 2nd Ed., Prentice Hall, Upper Saddle River, NJ.
Jeong, S., Lee, J., and Lee, C. J. (2004). “Slip effect at the pile-soil interface on dragload.” Comput. Geotech., 31(2), 115–126.
Kim, H., and Mission, J. L. C. (2011). “Development of negative skin friction on single piles: Uncoupled analysis based on nonlinear consolidation theory with finite strain and the load-transfer method.” Can. Geotech. J., 48(6), 905–914.
Ladd, C. C. (1991). “Stability evaluation during staged construction.” J. Geotech. Geoenviron. Eng., 117(4), 540–615.
Lam, S. Y., Ng, C. W. W., Leung, C. F., and Chan, S. H. (2009). “Centrifuge and numerical modeling of axial load effects on piles in consolidating ground.” Can. Geotech. J., 46(1), 10–24.
Lee, C. J., and Ng, W. W. (2004). “Development of down-drag on piles and pile groups in consolidating soil.” J. Geotech. Geoenviron. Eng., 130(9), 905–914.
McKenna, F., Scott, M. H., and Fenves, G. L. (2010). “Nonlinear finite element analysis software architecture using object composition.” J. Comput. Civ. Eng., 24(1), 95–107.
Meyerhof, G. G. (1976). “Bearing capacity and settlement of pile foundations.” J. Geotech. Engrg. Div., 102(3), 197–228.
Mosher, R. L. (1984). “Load transfer criteria for numerical analysis of axial loaded piles in sand.” Final Rep., U.S. Army Corps of Engineers, Waterways Experimental Station, Vicksburg, MS.
OpenSees 2.2.2 [Computer software]. Berkeley, CA, Pacific Earthquake Engineering Research Center.
Poulos, H. G., and Davis, E. H. (1980). Pile foundation analysis and design, Wiley, New York.
Reese, L. C., and O'Neill, M. W. (1988). “Drilled shafts: Construction procedures and design methods.” Rep. No. FHWA-HI-88-042, Office of Implementation, Federal Highway Administration, U.S. Department of Transportation, McLean, VA.
Salgado, R. (2008). The engineering of foundations, McGraw Hill, New York.
Simo, J. C., and Hughes, T. J. R. (1998). Computational inelasticity, Springer, Berlin.
Sun, T. K., and Yan, W. M. (2010). “Development of neutral plane on a pile in a consolidating ground.” Proc., 2nd Int. Symp. on Computational Mechanics, 1594–1599.
Vijayvergiya, V. N. (1977). “Load-movement characteristics of piles.” Proc., Ports 77 Conf., ASCE, Reston, VA.
Wong, K. S., and Teh, C. I. (1995). “Negative skin friction on piles in layered soil deposits.” J. Geotech. Eng., 121(6), 457–465.
Information & Authors
Information
Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 139 • Issue 9 • September 2013
Pages: 1433 - 1442
Copyright
© 2013 American Society of Civil Engineers.
History
Received: Jan 13, 2012
Accepted: Jan 7, 2013
Published online: Feb 9, 2013
Published in print: Sep 1, 2013
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.