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Sand deformation around an uplift plate anchor / Jinyuan Liu in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 6 (Juin 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 6 (Juin 2012) . - pp. 728–737 Titre : Sand deformation around an uplift plate anchor Type de document : texte imprimé Auteurs : Jinyuan Liu, Auteur ; Mingliang Liu, Auteur ; Zhende Zhu, Auteur Année de publication : 2012 Article en page(s) : pp. 728–737 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Anchor  Pullout  capacity  Scaled  model  Digital  image  correlation  Particle  image  velocimetry  Failure  mode Résumé : This paper presents an experimental investigation on soil deformation around uplift plate anchors in sand by using digital image correlation (DIC). The experimental setup consists of a camera, loading frame, plexiglass mold, and computer, which is developed to capture soil deformation during anchor uplifting. A series of model tests are performed to investigate the influence of particle size, soil density, and anchor embedment depth on soil deformation. A set of images captured during anchor uplifting are used to calculate soil displacement fields by DIC. The failure surface is studied by tracking the points with maximum shear strain values. On the basis of this study, it is found that soil deformation and the pullout resistance of plate anchors are substantially influenced by soil density and anchor embedment depth, whereas particle size within the studied range has limited influence. In dense sand, the shape of the failure surface changes from a truncated cone above a shallow anchor to a combined shape of a curved cone and a truncated cone for a deep anchor. In contrast, in loose sand a cone-shaped failure surface is formed within the soil mass above a shallow anchor; however, no failure surface is observed for a deep anchor, where the compressibility of soil is the dominating factor that influences the behavior of deep plate anchors in loose sand. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000633 [article] Sand deformation around an uplift plate anchor [texte imprimé] / Jinyuan Liu, Auteur ; Mingliang Liu, Auteur ; Zhende Zhu, Auteur . - 2012 . - pp. 728–737. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 6 (Juin 2012) . - pp. 728–737 Mots-clés : Anchor  Pullout  capacity  Scaled  model  Digital  image  correlation  Particle  image  velocimetry  Failure  mode Résumé : This paper presents an experimental investigation on soil deformation around uplift plate anchors in sand by using digital image correlation (DIC). The experimental setup consists of a camera, loading frame, plexiglass mold, and computer, which is developed to capture soil deformation during anchor uplifting. A series of model tests are performed to investigate the influence of particle size, soil density, and anchor embedment depth on soil deformation. A set of images captured during anchor uplifting are used to calculate soil displacement fields by DIC. The failure surface is studied by tracking the points with maximum shear strain values. On the basis of this study, it is found that soil deformation and the pullout resistance of plate anchors are substantially influenced by soil density and anchor embedment depth, whereas particle size within the studied range has limited influence. In dense sand, the shape of the failure surface changes from a truncated cone above a shallow anchor to a combined shape of a curved cone and a truncated cone for a deep anchor. In contrast, in loose sand a cone-shaped failure surface is formed within the soil mass above a shallow anchor; however, no failure surface is observed for a deep anchor, where the compressibility of soil is the dominating factor that influences the behavior of deep plate anchors in loose sand. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000633

Wave propagation in a pipe pile for low - strain integrity testing / Xuanming Ding in Journal of engineering mechanics, Vol. 137 N° 9 (Septembre 2011) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 137 N° 9 (Septembre 2011) . - pp.598-609 Titre : Wave propagation in a pipe pile for low - strain integrity testing Type de document : texte imprimé Auteurs : Xuanming Ding, Auteur ; Hanlong Liu, Auteur ; Jinyuan Liu, Auteur Année de publication : 2011 Article en page(s) : pp.598-609 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Wave  propagation  Tubular  structure  Pipe  pile  Low-strain  integrity  testing  Analytical  solution  Stress  wave Résumé : This paper presents an analytical solution methodology for a tubular structure subjected to a transient point loading in low-strain integrity testing. The three-dimensional effects on the pile head and the applicability of plane-section assumption are the main problems in low-strain integrity testing on a large-diameter tubular structure, such as a pipe pile. The propagation of stress waves in a tubular structure cannot be expressed by one-dimensional wave theory on the basis of plane-section assumption. This paper establishes the computational model of a large-diameter tubular structure with a variable wave impedance section, where the soil resistance is simulated by the Winkler model, and the exciting force is simulated with semisinusoidal impulse. The defects are classified into the change in the wall thickness and Young’s modulus. Combining the boundary and initial conditions, a frequency-domain analytical solution of a three-dimensional wave equation is deduced from the Fourier transform method and the separation of variables methods. On the basis of the frequency-domain analytic solution, the time-domain response is obtained from the inverse Fourier transform method. The three-dimensional finite-element models are used to verify the validity of analytical solutions for both an intact and a defective pipe pile. The analytical solutions obtained from frequency domain are compared with the finite-element method (FEM) results on both pipe piles in this paper, including the velocity time history, peak value, incident time arrival, and reflected wave crests. A case study is shown and the characteristics of velocity response time history on the top of an intact and a defective pile are investigated. The comparisons show that the analytical solution derived in this paper is reliable for application in the integrity testing on a tubular structure. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.org/emo/resource/1/jenmdt/v137/i9/p598_s1?isAuthorized=no [article] Wave propagation in a pipe pile for low - strain integrity testing [texte imprimé] / Xuanming Ding, Auteur ; Hanlong Liu, Auteur ; Jinyuan Liu, Auteur . - 2011 . - pp.598-609. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 137 N° 9 (Septembre 2011) . - pp.598-609 Mots-clés : Wave  propagation  Tubular  structure  Pipe  pile  Low-strain  integrity  testing  Analytical  solution  Stress  wave Résumé : This paper presents an analytical solution methodology for a tubular structure subjected to a transient point loading in low-strain integrity testing. The three-dimensional effects on the pile head and the applicability of plane-section assumption are the main problems in low-strain integrity testing on a large-diameter tubular structure, such as a pipe pile. The propagation of stress waves in a tubular structure cannot be expressed by one-dimensional wave theory on the basis of plane-section assumption. This paper establishes the computational model of a large-diameter tubular structure with a variable wave impedance section, where the soil resistance is simulated by the Winkler model, and the exciting force is simulated with semisinusoidal impulse. The defects are classified into the change in the wall thickness and Young’s modulus. Combining the boundary and initial conditions, a frequency-domain analytical solution of a three-dimensional wave equation is deduced from the Fourier transform method and the separation of variables methods. On the basis of the frequency-domain analytic solution, the time-domain response is obtained from the inverse Fourier transform method. The three-dimensional finite-element models are used to verify the validity of analytical solutions for both an intact and a defective pipe pile. The analytical solutions obtained from frequency domain are compared with the finite-element method (FEM) results on both pipe piles in this paper, including the velocity time history, peak value, incident time arrival, and reflected wave crests. A case study is shown and the characteristics of velocity response time history on the top of an intact and a defective pile are investigated. The comparisons show that the analytical solution derived in this paper is reliable for application in the integrity testing on a tubular structure. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.org/emo/resource/1/jenmdt/v137/i9/p598_s1?isAuthorized=no