Documents disponibles écrits par cet auteur

Influence of spatial variability on slope reliability using 2-D random fields / D. V. Griffiths in Journal of geotechnical and geoenvironmental engineering, Vol. 135 N° 10 (Octobre 2009) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 10 (Octobre 2009) . - pp. 1367–1378 Titre : Influence of spatial variability on slope reliability using 2-D random fields Type de document : texte imprimé Auteurs : D. V. Griffiths, Auteur ; Jinsong Huang, Auteur ; Gordon A. Fenton, Auteur Année de publication : 2009 Article en page(s) : pp. 1367–1378 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Slope  stabilityFinite  element  methodProbabilityFailures Résumé : The paper investigates the probability of failure of slopes using both traditional and more advanced probabilistic analysis tools. The advanced method, called the random finite-element method, uses elastoplasticity in a finite-element model combined with random field theory in a Monte-Carlo framework. The traditional method, called the first-order reliability method, computes a reliability index which is the shortest distance (in units of directional equivalent standard deviations) from the equivalent mean-value point to the limit state surface and estimates the probability of failure from the reliability index. Numerical results show that simplified probabilistic analyses in which spatial variability of soil properties is not properly accounted for, can lead to unconservative estimates of the probability of failure if the coefficient of variation of the shear strength parameters exceeds a critical value. The influences of slope inclination, factor of safety (based on mean strength values), and cross correlation between strength parameters on this critical value have been investigated by parametric studies in this paper. The results indicate when probabilistic approaches, which do not model spatial variation, may lead to unconservative estimates of slope failure probability and when more advanced probabilistic methods are warranted. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000099 [article] Influence of spatial variability on slope reliability using 2-D random fields [texte imprimé] / D. V. Griffiths, Auteur ; Jinsong Huang, Auteur ; Gordon A. Fenton, Auteur . - 2009 . - pp. 1367–1378. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 10 (Octobre 2009) . - pp. 1367–1378 Mots-clés : Slope  stabilityFinite  element  methodProbabilityFailures Résumé : The paper investigates the probability of failure of slopes using both traditional and more advanced probabilistic analysis tools. The advanced method, called the random finite-element method, uses elastoplasticity in a finite-element model combined with random field theory in a Monte-Carlo framework. The traditional method, called the first-order reliability method, computes a reliability index which is the shortest distance (in units of directional equivalent standard deviations) from the equivalent mean-value point to the limit state surface and estimates the probability of failure from the reliability index. Numerical results show that simplified probabilistic analyses in which spatial variability of soil properties is not properly accounted for, can lead to unconservative estimates of the probability of failure if the coefficient of variation of the shear strength parameters exceeds a critical value. The influences of slope inclination, factor of safety (based on mean strength values), and cross correlation between strength parameters on this critical value have been investigated by parametric studies in this paper. The results indicate when probabilistic approaches, which do not model spatial variation, may lead to unconservative estimates of slope failure probability and when more advanced probabilistic methods are warranted. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000099

Probabilistic analysis of coupled soil consolidation / Jinsong Huang in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 3 (Mars 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 3 (Mars 2010) . - pp. 417-430 Titre : Probabilistic analysis of coupled soil consolidation Type de document : texte imprimé Auteurs : Jinsong Huang, Auteur ; D. V. Griffiths, Auteur ; Gordon A. Fenton, Auteur Article en page(s) : pp. 417-430 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Finite-element  method  Soil  consolidation  Probabilistic  methods  Coupling Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Coupled Biot consolidation theory was combined with the random finite-element method to investigate the consolidation behavior of soil deposits with spatially variable properties in one-dimensional (1D) and two-dimensional (2D) spaces. The coefficient of volume compressibility (mv) and the soil permeability (k) are assumed to be lognormally distributed random variables. The random fields of mv and k are generated by the local average subdivision method which fully takes account of spatial correlation, local averaging, and cross correlations. The generated random variables are mapped onto a finite-element mesh and Monte Carlo finite-element simulations follow. The results of parametric studies are presented, which describe the effect of the standard deviation, spatial correlation length, and cross correlation coefficient on output statistics relating to the overall “equivalent” coefficient of consolidation. It is shown that the average degree of consolidation defined by excess pore pressure and settlement are different in heterogeneous soils. The dimensional effect on the soil consolidation behaviors is also investigated by comparing the 1D and 2D results. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JGGEFK&smode=strres [...] [article] Probabilistic analysis of coupled soil consolidation [texte imprimé] / Jinsong Huang, Auteur ; D. V. Griffiths, Auteur ; Gordon A. Fenton, Auteur . - pp. 417-430. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 3 (Mars 2010) . - pp. 417-430 Mots-clés : Finite-element  method  Soil  consolidation  Probabilistic  methods  Coupling Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Coupled Biot consolidation theory was combined with the random finite-element method to investigate the consolidation behavior of soil deposits with spatially variable properties in one-dimensional (1D) and two-dimensional (2D) spaces. The coefficient of volume compressibility (mv) and the soil permeability (k) are assumed to be lognormally distributed random variables. The random fields of mv and k are generated by the local average subdivision method which fully takes account of spatial correlation, local averaging, and cross correlations. The generated random variables are mapped onto a finite-element mesh and Monte Carlo finite-element simulations follow. The results of parametric studies are presented, which describe the effect of the standard deviation, spatial correlation length, and cross correlation coefficient on output statistics relating to the overall “equivalent” coefficient of consolidation. It is shown that the average degree of consolidation defined by excess pore pressure and settlement are different in heterogeneous soils. The dimensional effect on the soil consolidation behaviors is also investigated by comparing the 1D and 2D results. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JGGEFK&smode=strres [...]

Return mapping algorithms and stress predictors for failure analysis in geomechanics / Jinsong Huang in Journal of engineering mechanics, Vol. 135 N° 4 (Avril 2009) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 135 N° 4 (Avril 2009) . - pp. 276-284 Titre : Return mapping algorithms and stress predictors for failure analysis in geomechanics Type de document : texte imprimé Auteurs : Jinsong Huang, Auteur ; D. V. Griffiths, Auteur Article en page(s) : pp. 276-284 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Finite  element  method  Geotechnical  engineering  Failures  Constitutive  models  Elastoplasticity. Résumé : Two well-known return mapping algorithms, the closest point projection method (CPPM) and the cutting plane algorithm (CPA), have been analyzed in detail in relation to two classical failure problems in geomechanics, namely, bearing capacity and slope stability. The stability and efficiency of the algorithms have been investigated in relation to two types of stiffness operators, namely, the consistent elastoplastic modulus and the continuum elastoplastic modulus, and two types of stresses prediction strategies, namely, path independent (based on stresses at previous step) and path dependent (based on stresses at the previous iteration). The numerical experiments show that CPPM working with a consistent elastoplastic modulus and a path independent strategy gives the best performance. It was also observed, however, that the CPA with a continuum elastoplastic modulus and path dependent strategy was quite stable and efficient. This latter observation has implications for advanced constitutive modeling since CPA with a continuum elastoplastic modulus avoids the need for evaluation of the second derivatives of the plastic potential function, making it easier to deal with complicated yield surfaces. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...] [article] Return mapping algorithms and stress predictors for failure analysis in geomechanics [texte imprimé] / Jinsong Huang, Auteur ; D. V. Griffiths, Auteur . - pp. 276-284. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 135 N° 4 (Avril 2009) . - pp. 276-284 Mots-clés : Finite  element  method  Geotechnical  engineering  Failures  Constitutive  models  Elastoplasticity. Résumé : Two well-known return mapping algorithms, the closest point projection method (CPPM) and the cutting plane algorithm (CPA), have been analyzed in detail in relation to two classical failure problems in geomechanics, namely, bearing capacity and slope stability. The stability and efficiency of the algorithms have been investigated in relation to two types of stiffness operators, namely, the consistent elastoplastic modulus and the continuum elastoplastic modulus, and two types of stresses prediction strategies, namely, path independent (based on stresses at previous step) and path dependent (based on stresses at the previous iteration). The numerical experiments show that CPPM working with a consistent elastoplastic modulus and a path independent strategy gives the best performance. It was also observed, however, that the CPA with a continuum elastoplastic modulus and path dependent strategy was quite stable and efficient. This latter observation has implications for advanced constitutive modeling since CPA with a continuum elastoplastic modulus avoids the need for evaluation of the second derivatives of the plastic potential function, making it easier to deal with complicated yield surfaces. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...]