Evaluation and Prediction of 17th Street Canal I-Wall Stability Using Numerical Limit Analyses
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 139, Issue 6
Abstract
Numerical limit analyses have been used to evaluate the stability of the 17th Street Canal I-wall levee during Hurricane Katrina. The potential formation of a water-filled gap along the canal-side soil-wall interface at failure is included in both the lower- and upper-bound formulations. The analyses replicate published two-dimensional (2D) cross sections and soil properties developed in forensic investigations carried out by the Interagency Performance Evaluation Task Force (IPET) and by the Independent Levee Investigation Team (ILIT). The current results provide an independent basis for understanding and evaluating the proposed failure mechanisms and demonstrate that a water-filled gap is a necessary condition for the critical I-wall failure mechanism. Further limit-analysis calculations produce credible estimates of the surge elevation that caused failure of the 17th Street Canal I-wall as well as predictions of a consistent failure mechanism. The numerical limit analyses show clearly how differences in the stability of the I-wall are linked to different interpretations of the stratigraphy and undrained shear strengths by IPET and ILIT. The analyses also show that effects of a thin layer of weak organic clay as postulated by ILIT are not necessary to explain the I-wall failure.
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Acknowledgments
The second author (AJW) served as a member of the NRC Committee on New Orleans Regional Hurricane Protection Projects and was closely involved in reviewing geotechnical aspects of the work conducted by IPET. The first Author (YY) has been partially supported by the National Research Foundation of Singapore and the Singapore-MIT Alliance for Research and Technology (SMART) through the Center for Environmental Modeling and Sensing (CENSAM).
References
Bolton, M. D., and Powrie, W. (1987). “The collapse of diaphragm walls retaining clay.” Geotechnique, 37(3), 335–353.
Brinkgreve, R., ed. (2007). PLAXIS 2D. Version 8.5 finite-element code for soil and rock analyses: Complete set of manuals, Balkema, Rotterdam, Netherlands.
Brinkgreve, R. B. J., and Bakker, H. L. (1991). “Non-linear finite element analysis of safety factors.” Proc., 7th Int. Conf. on Computational Methods and Advances in Geomechanics, Balkema, Rotterdam, Netherlands, 1117–1122.
Duncan, J. M., Brandon, T. L., Wright, S. G., and Vroman, N. (2008). “Stability of I-walls in New Orleans during Hurricane Katrina.” J. Geotech. Geoenviron. Eng., 134(5), 681–691.
Independent Levee Investigation Team (ILIT) (2006). “Investigation of the performance of the New Orleans regional flood protection systems during Hurricane Katrina.” Final Rep. 〈http://www.ce.berkeley.edu/projects/neworleans/〉 (July 31, 2006).
Interagency Performance Evaluation Task Force (IPET) (2007). “Performance evaluation of the New Orleans and southeast Louisiana hurricane protection system.” Final Rep. of the Interagency Performance Evaluation Task Force, U.S. Army Corps of Engineers 〈https://ipet.wes.army.mil〉.
Krahn, J. (2004). Stability modeling with SLOPE/W, an engineering methodology, SLOPE/W 2004 software manual, GEO-SLOPE/W Int., Ltd., Calgary, AB, Canada.
Ladd, C. C. (2009). “Discussion of ‘Stability of I-walls in New Orleans during Hurricane Katrina’ by Duncan et al.” J. Geotech. Geoenviron. Eng., 135(12), 1999–2002.
Lambe, T. W., and Whitman, R. V. (1969). Soil mechanics, Wiley, New York.
Sasanakul, I., et al. (2008). “New Orleans levee system performance during Hurricane Katrina: 17th Street Canal and Orleans Canal North.” J. Geotech. Geoenviron. Eng., 134(5), 657–667.
Seed, R. B., et al. (2008c). “New Orleans and Hurricane Katrina. III: The 17th Street drainage canal.” J. Geotech. Geoenviron. Eng., 134(5), 740–761.
Sloan, S. W. (1988a). “Lower bound limit analysis using finite elements and linear programming.” Int. J. Numer. Anal. Methods Geomech., 12(1), 61–77.
Sloan, S. W. (1988b). “A steepest edge active set algorithm for solving sparse linear programming problems.” Int. J. Numer. Anal. Methods Geomech., 26(12), 2671–2685.
Sloan, S. W., and Kleeman, P. W. (1995). “Upper bound limit analysis using discontinuous velocity fields.” Comput. Methods Appl. Mech. Eng., 127(1–4), 293–314.
Spencer, E. (1967). “A method of analysis of the stability of embankments assuming parallel interslice forces.” Geotechnique, 17(1), 11–26.
Ukritchon, B., Whittle, A. J., and Sloan, S. W. (1998). “Undrained limit analyses for combined loading of strip footing on clay.” J. Geotech. Geoenviron. Eng., 124(3), 265–276.
Ukritchon, B., Whittle, A. J., and Sloan, S. W. (2003). “Undrained stability of braced excavations in clay.” J. Geotech. Geoenviron. Eng., 129(8), 738–754.
Wright, S. G. (1999). UTEXAS4—A computer program for slope stability calculations, UTEXAS 4 software manual, Shinoak Software, Austin, TX.
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© 2013 American Society of Civil Engineers.
History
Received: Mar 7, 2010
Accepted: Aug 3, 2012
Published online: Aug 15, 2012
Published in print: Jun 1, 2013
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