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To facilitate the design of seismic remediation for Tuttle Creek Dam in east central Kansas, a seismic finite difference analysis of the dam was performed using the software FLAC and the UBCSAND and UBCTOT soil constitutive models. The FLAC software has a key advantage because it can use calibrated site-specific constitutive models. Earlier deformation analyses using a hyperbolic constitutive model for the foundation fine-grained materials did not properly represent the modulus and strength reduction and predicted extremely large permanent deformations. Cyclic triaxial laboratory tests using high-quality samples and in situ vane shear tests were used to calibrate the FLAC constitutive model herein. The resulting FLAC analysis of the unremediated dam predicted an upstream slope toe deformation of about 0.6 m, a crest settlement of about 0.6 m, and a downstream slope toe deformation of about 1.5 m using the design ground motion. Based on the estimated permanent deformations and other factors, it was decided that the anticipated upstream slope and crest deformations were tolerable and only the downstream slope had to be remediated to protect the downstream seepage control system. Key words: earthquakes, liquefaction, numerical analysis, shear strength, post-liquefaction, slope stability. Resume : Dans le but d'assister la conception de la rehabilitation sismique du barrage de Tuttle Creek dans le centre est du Kansas, une analyse sismique du barrage par difference finie a ete realisee a l'aide du logiciel FLAC et des modeles constitutifs de sols UBCSAND et UBCTOT. Le logiciel FLAC est avantageux puisqu'il peut utiliser des modeles constitutifs calibres pour un site specifique. Des analyses anterieures faites avec un modele constitutif hyperbolique pour des materiaux fins de fondation n' a pas pu representer adequatement la reduction du module et de la resistance et a predit des deformations permanentes extremement grandes. Pour la presente etude, des essais triaxiaux cycliques en laboratoire avec des echantillons de qualite elevee et des essais scissometriques in situ ont ete utilises pour calibrer le modele constitutif de FLAC. L'analyse par FLAC du barrage non rehabilite a predit une deformation du pied de la pente en amont d' environ 0,6 m, un tassement de la crete d'environ 0,6 m, et une deformation du pied de la pente en aval d'environ 1,5 m, et ce, en utilisant les mouvements du sol de conception. Base sur les deformations permanentes estimees et d'autres facteurs, il a ete decide que les deformations anticipees sur la pente en amont et sur la crete sont tolerables et que seulement la pente en aval doit etre rehabilitee afin de proteger le systeme de controle des exfiltrations en aval. Mots-cles : seismes, liquefaction, analyse numerique, resistance au cisaillement, post-liquefaction, stabilite de pente. [Traduit par la Redaction], Introduction Tuttle Creek Dam, located on the Big Blue River in the Kansas River Basin, is part of a system that provides a comprehensive plan for flood control and other [...]

The US Army Corps of Engineers (USACE) completed a liquefaction potential analysis as part of the seismic evaluation of Milford Dam in 1986. This paper uses data from the 1986 study to compare fines content data from in situ frozen and standard penetration test (SPT) samples that suggest fines content can be overestimated by 1-10% by SPT samples in stratified sand deposits. This result may have implications for liquefaction assessments because split-spoon samples may overestimate the actual fines content, resulting in a liquefiable deposit being classified as nonliquefiable. In addition, the paper evaluates the effectiveness of ground freezing on maintaining in situ soil structure and aging of the foundation sands at Milford Dam. Key words: soil mechanics, liquefaction, shear strength, cone penetration test, standard penetration test, seismic stability., Introduction Milford Dam is a US Army Corps of Engineers (USACE), Kansas City District (KCD) project, located on the Republican River in east central Kansas. The site is 6.5 km [...]