Support Mechanisms of Rammed Aggregate Piers. II: Numerical Analyses
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Volume 133, Issue 12
Abstract
This paper is the second of a two-part series describing an investigation of the mechanical behavior of rammed aggregate piers in supporting rigid square footings. In this paper, the performances of two pier-supported footings and three isolated piers during compressive load tests were simulated using an axisymmetric finite element model and compared to experimental data. A hardening-soil constitutive model with parameters estimated from in situ and laboratory tests was used to characterize the constitutive behaviors of the pier material and the matrix soil. Pier groups were modeled as unit cells with the tributary area determined from the center-to-center spacing. Cavity expansion modeling was used to simulate the pier installation process. Verifications of the numerical model were carried out by comparing the numerical results with the data obtained from full-scale, instrumented load tests. Interpretation of the numerical results focused on the load-deformation behavior, group effect, stress concentration ratio, and the development of stresses in the matrix soil. The distributions of vertical stress underneath the pier-supported footings are also characterized.
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Acknowledgments
This research was sponsored by the Geopier Foundation Company, Inc. and Iowa State University of Science and Technology. The support of these agencies is greatly acknowledged. Valuable comments and suggestions were provided by Dr. Kord Wissmann. The reviewers of this paper provided excellent reviews and very worthwhile suggestions.
References
Aboshi, H., Ichimoto, E., Enoki, M., and Harada, K. (1979). “The compozer: A method to improve characteristics of soft clays by inclusions of large diameter sand columns.” Proc., Int. Conf. on Soil Reinforcement: Reinforced Earth and Other Techniques, Vol. 1, Paris, 211–216.
Balaam, N. P., and Brooker, J. R. (1981). “Analysis of rigid rafts supported by granular piles.” Int. J. Numer. Analyt. Meth. Geomech., 5(4), 379–403.
Barksdale, R. D., and Bachus, R. C. (1983). “Design and construction of stone columns.” Rep. No. FHWA/RD-83/026, National Technical Information Service, Springfield, Va.
Dunnicliff, J. (1993). Geotechnical instrumentation for monitoring field performance, Wiley, New York.
Fox, N. S., and Cowell, M. J. (1998). foundation and soil reinforcement manual, Geopier Foundation, Blacksburg, Va.
Handy, R. L., Fox, N. S., and Wissmann, K. J. (1999). “Short aggregate piers reinforce soils near tunnels.” Proc., Geo-Engineering for Underground Facilities, Geotechnical Special Publication No. 90, ASCE, Reston, Va., 1039–1047.
Kirsch, F., and Sondermann, W. (2001). “Ground improvement and its numerical analysis.” Proc., 15th Int. Conf. on Soil Mechanics and Foundation Engineering, ISSMGE, Istanbul, Turkey, 1775–1778.
Lambe, T. (1967). “The stress-path methods.” ASCE:JSMFD, 93(6), 309–331.
Lawton, E. C., and Fox, N. S. (1994). “Settlement of structures supported on marginal or inadequate soils stiffened with short aggregate piers.” Proc. Vertical and Horizontal Deformations of Foundations and Embankments, Geotechnical Special Publication No. 40, ASCE, College Station, Tex., Vol. 2, 962–974.
Lawton, E. C., Fox, N. S., and Handy, R. L. (1994). “Control of settlement and uplift structures using short aggregate piers.” Proc., In-Situ Deep Soil Improvement, Geotechnical Special Publication No. 45, ASCE, Atlanta, 121–132.
Lawton, E. C., and Warner, B. J. (2004). “Performance of a group of Geopier elements loaded in compression compared to single Geopier elements and unreinforced soil.” Final Rep., Rep. No. UUCVEEN 04-12, Univ. of Utah, Salt Lake City.
Lee, J. S., and Pande, G. N. (1998). “Analysis of stone-column reinforced foundations.” Int. J. Numer. Analyt. Meth. Geomech., 22(12), 1001–1020.
Mitchell, J. K., and Huber, T. R. (1985). “Performance of stone column foundation.” J. Geotech. Engrg., 111(2), 205–223.
Pham, H. (2005). “Support mechanism for rammed aggregate piers.” Ph.D. Dissertation, Iowa State University, Ames, Iowa.
Potts, D. M., and Zdravkovic, L. (1999). Finite element analysis in geotechnical engineering: Vol. I—Theory, Telford, London.
Schanz, T., Vermeer, P. A., and Bonnier, P. G. (1999). “Formulation and verification of the hardening-soil model.” Proc., Beyond 2000 in Computational Geotechnics, Balkema, Rotterdam, The Netherlands, 281–290.
White, D. J., Gaul, A. J., and Hoevelkamp, K. (2003). “Highway applications for rammed aggregate pier in Iowa soils.” Final Rep., DOT TR-443, Ames, Iowa.
White, D. J., Pham, H. T. V., and Hoevelkamp, K. K. (2007). “Support mechanisms of rammed aggregate piers. I: Experimental results.” J. Geotech. Geoenviron. Eng., 133(12), 1503–1511.
White, D. J., Suleiman, M. T., Pham, H. T., and Bigelow, J. (2002). “Constitutive equations for aggregates used in foundation construction. Final Rep., Iowa State Univ., Ames, Iowa.
Wissmann, K. J., Moser, K., and Pando, M. (2001). “Reducing settlement risks in residual piedmont soil using rammed aggregate pier elements.” Proc., Foundations and Ground Improvement, Geotechnical Special Publication No. 113, ASCE, Blacksburg, Va, 943–957.
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Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 133 • Issue 12 • December 2007
Pages: 1512 - 1521
Copyright
© 2007 ASCE.
History
Received: Dec 13, 2005
Accepted: Jan 6, 2007
Published online: Dec 1, 2007
Published in print: Dec 2007
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