Reevaluation of the Gap Formation in the New Orleans Levee System
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 140, Issue 3
Abstract
In the aftermath of Hurricane Katrina, studies pointed out that gap formation was related to breaches of many floodwalls in New Orleans. However, it is still necessary to discern whether those gaps were the cause or the result of the failure to justify the application of retrofitting techniques designed to correct gap formation problems. For that purpose, this study conducted numerical and analytical evaluations to investigate the in-depth mechanism of gap formation using an effective stress approach. To this end, it was found that gap was the cause of failure for the London Ave. canal because of the seepage effect; however, it could be the result of failure for the 17th St. canal because of the subsidence of the soft soil layer underneath the levee. When the stiffness and strength of the soft layer were increased considering the geotechnical variability in the numerical analysis for the 17th St. canal, however, it showed that the failure mode changed and gap became the cause of failure, meaning that the question of whether gap is the cause or the result of failure depends on the subtle difference in geotechnical conditions. This result also implied that the gap formation as a possible cause of failure must be considered in planning the retrofitting techniques even for the area where gap was not the immediate cause of the failure.
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Acknowledgments
The authors appreciate the funding received under a subcontract from the Department of Homeland Security–sponsored Southeast Region Research Initiative at the DOE’s Oak Ridge National Laboratory.
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Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 140 • Issue 3 • March 2014
Copyright
© 2013 American Society of Civil Engineers.
History
Received: Dec 21, 2011
Accepted: Aug 7, 2013
Published online: Aug 10, 2013
Published in print: Mar 1, 2014
Discussion open until: Apr 29, 2014
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