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dc.contributor.authorVanden Berge, Danielen_US
dc.date.accessioned2015-10-17T06:00:33Z
dc.date.available2015-10-17T06:00:33Z
dc.date.issued2014-04-24en_US
dc.identifier.othervt_gsexam:2468en_US
dc.identifier.urihttp://hdl.handle.net/10919/56955
dc.description.abstractRapid drawdown (RDD) occurs when the water level adjacent to a slope or embankment is lowered quickly after a long period of being elevated either at the normal operating level for a dam or in the case of levees, during a prolonged flood. The current state of practice for RDD analysis is a multi-stage undrained strength method based on limit equilibrium. The primary objective of this research was to develop a new method for rapid drawdown based on the finite element method. The new method estimates undrained strengths based on effective consolidation stresses from finite element analysis and the results of isotropically consolidated undrained triaxial compression (ICU-TC) tests. The field strengths appropriate for use with this rapid drawdown method were found to be on average 70% of the strength measured in ICU-TC tests based on back analysis of rapid drawdown failures. For rapid drawdown, anisotropic consolidation, plane strain deformation, and principal stress rotation were shown to produce field undrained strengths in the range of 60 to 80% of the strengths measured in isotropically consolidated undrained (ICU) triaxial compression. The current limit equilibrium method for rapid drawdown was shown to produce a similar reduction in ICU-TC strength. This study also investigated other issues related to RDD. Effective stress analysis of RDD, especially using uncoupled transient seepage analysis, was shown to be inappropriate because important aspects of soil behavior are ignored. Consolidated-undrained strength tests on compacted clay specimens highlighted the importance of relative compaction on undrained strength. Anisotropic consolidation was shown to produce lower undrained strengths in triaxial compression than isotropic consolidation, especially at higher consolidation stresses. The behavior of compacted specimens under principal stress rotation was investigated using triaxial and direct simple shear tests. Finally probabilistic methods were applied to RDD to assess the probability that the factor of safety is less than one, assuming RDD occurs.en_US
dc.format.mediumETDen_US
dc.publisherVirginia Techen_US
dc.rightsThis Item is protected by copyright and/or related rights. Some uses of this Item may be deemed fair and permitted by law even without permission from the rights holder(s), or the rights holder(s) may have licensed the work for use under certain conditions. For other uses you need to obtain permission from the rights holder(s).en_US
dc.subjectrapid drawdownen_US
dc.subjectfinite element analysisen_US
dc.subjectundrained strengthen_US
dc.subjectcompacted clayen_US
dc.subjectreliability analysisen_US
dc.titleRapid Drawdown Analysis using the Finite Element Methoden_US
dc.typeDissertationen_US
dc.contributor.departmentCivil and Environmental Engineeringen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineCivil Engineeringen_US
dc.contributor.committeechairDuncan, James Michaelen_US
dc.contributor.committeechairBrandon, Thomas L.en_US
dc.contributor.committeememberDove, Joseph E.en_US
dc.contributor.committeememberFilz, George M.en_US


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