Documents disponibles écrits par cet auteur

Effect of spatial correlation of cone tip resistance on the bearing capacity of piles / Jin-Jian Chen in Journal of geotechnical and geoenvironmental engineering, Vol. 139 N° 3 (Mars 2013) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 139 N° 3 (Mars 2013) . - pp. 494-500 Titre : Effect of spatial correlation of cone tip resistance on the bearing capacity of piles Type de document : texte imprimé Auteurs : Jin-Jian Chen, Auteur ; Lianyang Zhang, Auteur Année de publication : 2013 Article en page(s) : pp. 494-500 Note générale : geotechnique Langues : Anglais (eng) Mots-clés : piles;  load  bearing  capacity;  safety;  risk  management;  spatial  analysis Résumé : The cone tip resistance (qc) from cone penetration tests (CPTs) is widely used to determine the bearing capacity of piles. Although it is widely known that soil properties are spatially correlated, the spatial correlation of qc is not considered in the current methods for predicting the bearing capacity of piles. In this paper, a probabilistic approach is presented for predicting the bearing capacity of driven piles in clay by considering the spatial correlation between qcsVn (the spatial average of qc of the bottom soil layer within the pile length) and qcbV (the spatial average of qc over an interval near the pile base). Parametric studies are conducted to evaluate the effect of the spatial correlation between qcsVn and qcbV on the bearing capacity of piles. The results indicate that it is important to consider the spatial correlation between qcsVn and qcbV in the probabilistic prediction of the bearing capacities of piles. Ignoring the spatial correlation between qcsVn and qcbV will underestimate the probability of failure and lead to unsafe design. Finally, 14 field test piles are analyzed with the presented approach to demonstrate the probabilistic prediction of the bearing capacity of piles by considering the spatial correlation of the CPT data. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000775 [article] Effect of spatial correlation of cone tip resistance on the bearing capacity of piles [texte imprimé] / Jin-Jian Chen, Auteur ; Lianyang Zhang, Auteur . - 2013 . - pp. 494-500. geotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 139 N° 3 (Mars 2013) . - pp. 494-500 Mots-clés : piles;  load  bearing  capacity;  safety;  risk  management;  spatial  analysis Résumé : The cone tip resistance (qc) from cone penetration tests (CPTs) is widely used to determine the bearing capacity of piles. Although it is widely known that soil properties are spatially correlated, the spatial correlation of qc is not considered in the current methods for predicting the bearing capacity of piles. In this paper, a probabilistic approach is presented for predicting the bearing capacity of driven piles in clay by considering the spatial correlation between qcsVn (the spatial average of qc of the bottom soil layer within the pile length) and qcbV (the spatial average of qc over an interval near the pile base). Parametric studies are conducted to evaluate the effect of the spatial correlation between qcsVn and qcbV on the bearing capacity of piles. The results indicate that it is important to consider the spatial correlation between qcsVn and qcbV in the probabilistic prediction of the bearing capacities of piles. Ignoring the spatial correlation between qcsVn and qcbV will underestimate the probability of failure and lead to unsafe design. Finally, 14 field test piles are analyzed with the presented approach to demonstrate the probabilistic prediction of the bearing capacity of piles by considering the spatial correlation of the CPT data. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000775

Field tests, modification, and application of deep soil mixing method in soft clay / Jin-Jian Chen in Journal of geotechnical and geoenvironmental engineering, Vol. 139 N° 1 (Janvier 2013) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 139 N° 1 (Janvier 2013) . - pp. 24–34 Titre : Field tests, modification, and application of deep soil mixing method in soft clay Type de document : texte imprimé Auteurs : Jin-Jian Chen, Auteur ; Lianyang Zhang, Auteur ; Jun-Feng Zhang, Auteur Année de publication : 2013 Article en page(s) : pp. 24–34 Note générale : geotechnique Langues : Anglais (eng) Mots-clés : soil  stabilization;  field  tests;  soil  mixing;  clays;  pore  water;  water  pressure Résumé : The installation of soil-cement columns causes excess pore-water pressures and movements of surrounding ground, which affect adjacent underground structures. In Shanghai, a triple-shaft deep soil mixing (DSM) method has been proposed and is widely used to minimize the installation effects. However, when this DSM method was used to install soil-cement columns close to a Metro tunnel, unacceptable soil displacement was caused, even at the very beginning. Therefore, it was decided to conduct field tests to investigate the effect of major factors affecting DSM installations and then modify the construction parameters so that the soil displacement caused by DSM construction would not exceed the allowable limit. The field tests consisted of two phases: Phase I tests of single DSM column installations close to the Metro tunnel to modify the construction parameters, and Phase II tests of continuous multiple DSM column installations far from the Metro tunnel to validate the modified construction parameters. Detailed pore-water pressure and soil displacement measurements were conducted during the field tests. Based on the field tests, the traditional DSM method was modified by using a higher water/cement ratio, lower mixing speed, and no injection during withdrawal, and adopting a new installation sequence for continuous construction that started from the farthest row and moved closer to the tunnel. Using the modified construction parameters, the triple-shaft DSM method was successfully applied to the large-scale soil improvement of an underground highway excavation project close to the Metro tunnels. This paper describes the background, the field tests, the modified DSM method, and its successful application. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000746 [article] Field tests, modification, and application of deep soil mixing method in soft clay [texte imprimé] / Jin-Jian Chen, Auteur ; Lianyang Zhang, Auteur ; Jun-Feng Zhang, Auteur . - 2013 . - pp. 24–34. geotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 139 N° 1 (Janvier 2013) . - pp. 24–34 Mots-clés : soil  stabilization;  field  tests;  soil  mixing;  clays;  pore  water;  water  pressure Résumé : The installation of soil-cement columns causes excess pore-water pressures and movements of surrounding ground, which affect adjacent underground structures. In Shanghai, a triple-shaft deep soil mixing (DSM) method has been proposed and is widely used to minimize the installation effects. However, when this DSM method was used to install soil-cement columns close to a Metro tunnel, unacceptable soil displacement was caused, even at the very beginning. Therefore, it was decided to conduct field tests to investigate the effect of major factors affecting DSM installations and then modify the construction parameters so that the soil displacement caused by DSM construction would not exceed the allowable limit. The field tests consisted of two phases: Phase I tests of single DSM column installations close to the Metro tunnel to modify the construction parameters, and Phase II tests of continuous multiple DSM column installations far from the Metro tunnel to validate the modified construction parameters. Detailed pore-water pressure and soil displacement measurements were conducted during the field tests. Based on the field tests, the traditional DSM method was modified by using a higher water/cement ratio, lower mixing speed, and no injection during withdrawal, and adopting a new installation sequence for continuous construction that started from the farthest row and moved closer to the tunnel. Using the modified construction parameters, the triple-shaft DSM method was successfully applied to the large-scale soil improvement of an underground highway excavation project close to the Metro tunnels. This paper describes the background, the field tests, the modified DSM method, and its successful application. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000746

Method for estimating the deformability of heavily jointed rock masses / Lianyang Zhang in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1242-1250 Titre : Method for estimating the deformability of heavily jointed rock masses Type de document : texte imprimé Auteurs : Lianyang Zhang, Auteur Année de publication : 2010 Article en page(s) : pp. 1242-1250 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Jointed  rock  mass  Deformability  Equivalent  continuum  Analytical  expression Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Determination of the deformability of jointed rock masses is an important and challenging task in rock mechanics and rock engineering. In this paper, simple expressions are derived for estimating the equivalent isotropic deformation properties of heavily jointed rock masses using the methodology of equivalent continuum approach. The derived expressions are compared with two analytical relations in the literature and the field test data relating rock quality designation (RQD) and deformation modulus ratio Em/Er, where Em and Er are the deformation modulus of the rock mass and the intact rock, respectively. The derived expressions are in reasonable agreement with the existing analytical relations in the literature and satisfactorily predict the range of the field RQD versus modulus ratio Em/Er data. Finally two examples are presented to demonstrate the application of the derived expressions by applying them to estimate the deformation modulus of jointed rock mass at two sites. The results of the paper can be of help in predicting the deformation behavior of jointed rock masses when the properties of the intact rock and discontinuities are available. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1242_s1?isAuthorized=no [article] Method for estimating the deformability of heavily jointed rock masses [texte imprimé] / Lianyang Zhang, Auteur . - 2010 . - pp. 1242-1250. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 9 (Septembre 2010) . - pp. 1242-1250 Mots-clés : Jointed  rock  mass  Deformability  Equivalent  continuum  Analytical  expression Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Determination of the deformability of jointed rock masses is an important and challenging task in rock mechanics and rock engineering. In this paper, simple expressions are derived for estimating the equivalent isotropic deformation properties of heavily jointed rock masses using the methodology of equivalent continuum approach. The derived expressions are compared with two analytical relations in the literature and the field test data relating rock quality designation (RQD) and deformation modulus ratio Em/Er, where Em and Er are the deformation modulus of the rock mass and the intact rock, respectively. The derived expressions are in reasonable agreement with the existing analytical relations in the literature and satisfactorily predict the range of the field RQD versus modulus ratio Em/Er data. Finally two examples are presented to demonstrate the application of the derived expressions by applying them to estimate the deformation modulus of jointed rock mass at two sites. The results of the paper can be of help in predicting the deformation behavior of jointed rock masses when the properties of the intact rock and discontinuities are available. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i9/p1242_s1?isAuthorized=no