Les Inscriptions à la Bibliothèque sont ouvertes en
ligne via le site: https://biblio.enp.edu.dz
Les Réinscriptions se font à :
• La Bibliothèque Annexe pour les étudiants en
2ème Année CPST
• La Bibliothèque Centrale pour les étudiants en Spécialités
A partir de cette page vous pouvez :
| Retourner au premier écran avec les recherches... |
Journal of geotechnical and geoenvironmental engineering (ASCE) |
Dépouillements
Ajouter le résultat dans votre panierBearing capacity of spatially random cohesive soil using numerical limit analyses / Kiyonobu Kasama in Journal of geotechnical and geoenvironmental engineering, Vol. 137 N° 11 (Novembre 2011)
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 989-996
Titre : Bearing capacity of spatially random cohesive soil using numerical limit analyses Type de document : texte imprimé Auteurs : Kiyonobu Kasama, Auteur ; Andrew J. Whittle, Auteur Année de publication : 2012 Article en page(s) : pp. 989-996 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Bearing capacity Cohesive soil Limit analysis Monte Carlo method Random field Probabilistic analysis Résumé : This paper describes a probabilistic study of the two-dimensional bearing capacity of a vertically loaded strip footing on spatially random, cohesive soil using numerical limit analyses (NLA-CD). The analyses use a Cholesky decomposition (CD) technique with midpoint discretization to represent the spatial variation in undrained shear strength within finite-element meshes for both upper- and lower-bound analyses and assumes an isotropic correlation length. Monte Carlo simulations are then used to interpret the bearing capacity for selected ranges of the coefficient of variation in undrained shear strength and the ratio of correlation length to footing width. The results are compared directly with data from a very similar study in which bearing capacity realizations were computed using a method of local average subdivision (LAS) in a conventional displacement-based finite-element method (FEM-LAS). These comparisons show the same qualitative features but suggest that the published FEM calculations tend to overestimate the probability of failure at large correlation lengths. The NLA method offers a more convenient and computationally efficient approach for evaluating effects of variability in soil strength properties in geotechnical stability calculations. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p989_s1?isAuthorized=no [article] Bearing capacity of spatially random cohesive soil using numerical limit analyses [texte imprimé] / Kiyonobu Kasama, Auteur ; Andrew J. Whittle, Auteur . - 2012 . - pp. 989-996.
Géotechnique
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 989-996
Mots-clés : Bearing capacity Cohesive soil Limit analysis Monte Carlo method Random field Probabilistic analysis Résumé : This paper describes a probabilistic study of the two-dimensional bearing capacity of a vertically loaded strip footing on spatially random, cohesive soil using numerical limit analyses (NLA-CD). The analyses use a Cholesky decomposition (CD) technique with midpoint discretization to represent the spatial variation in undrained shear strength within finite-element meshes for both upper- and lower-bound analyses and assumes an isotropic correlation length. Monte Carlo simulations are then used to interpret the bearing capacity for selected ranges of the coefficient of variation in undrained shear strength and the ratio of correlation length to footing width. The results are compared directly with data from a very similar study in which bearing capacity realizations were computed using a method of local average subdivision (LAS) in a conventional displacement-based finite-element method (FEM-LAS). These comparisons show the same qualitative features but suggest that the published FEM calculations tend to overestimate the probability of failure at large correlation lengths. The NLA method offers a more convenient and computationally efficient approach for evaluating effects of variability in soil strength properties in geotechnical stability calculations. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p989_s1?isAuthorized=no
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 997-1008
Titre : Quantitative estimation of clay mineralogy in fine-grained soils Type de document : texte imprimé Auteurs : Bhaskar Chittoori, Auteur ; Anand J. Puppala, Auteur Année de publication : 2012 Article en page(s) : pp. 997-1008 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Clay mineralogy Montmorillonite Kaolinite Expansive soil Mineral quantification Artificial neural networks Résumé : Stabilization design guidelines based on soil plasticity properties have certain limitations. Soils of similar plasticity properties can contain different dominant clay minerals, and hence, their engineering behavior can be different when stabilized with the same chemical additive and dosage. It is essential to modify stabilizer design guidelines by including clay mineralogy of the soil and its interactions with chemical additives used. Chemical properties of a soil including cation exchange capacity (CEC), specific surface area (SSA) and total potassium (TP) are dependent on clay mineral constituents, and an attempt is made in this study to develop a rational and practical methodology to determine both clay mineralogy distribution and dominant clay mineral in a soil by using three measured chemical soil properties and their analyses. This approach has been evaluated by determining and evaluating clay minerals present in artificial and natural clayey soils of known and unknown clay mineralogy. A total of twenty natural and six artificial soils were considered and used in the chemical analyses. Test results and subsequent analyses including the development of artificial neural network (ANN) based models are evaluated and described in this paper. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p997_s1?isAuthorized=no [article] Quantitative estimation of clay mineralogy in fine-grained soils [texte imprimé] / Bhaskar Chittoori, Auteur ; Anand J. Puppala, Auteur . - 2012 . - pp. 997-1008.
Géotechnique
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 997-1008
Mots-clés : Clay mineralogy Montmorillonite Kaolinite Expansive soil Mineral quantification Artificial neural networks Résumé : Stabilization design guidelines based on soil plasticity properties have certain limitations. Soils of similar plasticity properties can contain different dominant clay minerals, and hence, their engineering behavior can be different when stabilized with the same chemical additive and dosage. It is essential to modify stabilizer design guidelines by including clay mineralogy of the soil and its interactions with chemical additives used. Chemical properties of a soil including cation exchange capacity (CEC), specific surface area (SSA) and total potassium (TP) are dependent on clay mineral constituents, and an attempt is made in this study to develop a rational and practical methodology to determine both clay mineralogy distribution and dominant clay mineral in a soil by using three measured chemical soil properties and their analyses. This approach has been evaluated by determining and evaluating clay minerals present in artificial and natural clayey soils of known and unknown clay mineralogy. A total of twenty natural and six artificial soils were considered and used in the chemical analyses. Test results and subsequent analyses including the development of artificial neural network (ANN) based models are evaluated and described in this paper. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p997_s1?isAuthorized=no
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1009-1018
Titre : Performance and prediction of vacuum combined surcharge consolidation at port of brisbane Type de document : texte imprimé Auteurs : Buddhima Indraratna, Auteur ; Cholachat Rujikiatkamjorn, Auteur ; Jay Ameratunga, Auteur Année de publication : 2012 Article en page(s) : pp. 1009-1018 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Consolidation Soil improvement Vertical drains Vacuum Résumé : During the past decade, the application of vacuum preloading for stabilizing soft coastal clay and other low-lying estuarine soils has become popular in Australia. The cost-effectiveness is a major factor in most projects in view of the significantly reduced time for achieving a relatively high degree of consolidation. Resulting from an increase in trade activities at the Port of Brisbane, new facilities on Fisherman Islands at the mouth of the Brisbane River will be constructed on the new outer area (235 ha) adjacent to the existing port facilities through land reclamation. A vacuum-assisted surcharge load and conventional surcharge scheme in conjunction with prefabricated vertical drains was selected to reduce the required consolidation time through the deeper subsoil layers. The design of the combined vacuum and surcharge fill system and the construction of the embankment are described in this paper. A comparison of the performance of the vacuum combined surcharge loading system with a standard surcharge fill highlights the clear benefits of vacuum consolidation. Field monitoring data are presented to demonstrate how the embankment performed during construction. An analytical solution for radial consolidation considering both time-dependent surcharge loading and vacuum pressure is proposed to predict the settlements and associated excess pore pressures of the soft Holocene clay deposits. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1009_s1?isAuthorized=no [article] Performance and prediction of vacuum combined surcharge consolidation at port of brisbane [texte imprimé] / Buddhima Indraratna, Auteur ; Cholachat Rujikiatkamjorn, Auteur ; Jay Ameratunga, Auteur . - 2012 . - pp. 1009-1018.
Géotechnique
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1009-1018
Mots-clés : Consolidation Soil improvement Vertical drains Vacuum Résumé : During the past decade, the application of vacuum preloading for stabilizing soft coastal clay and other low-lying estuarine soils has become popular in Australia. The cost-effectiveness is a major factor in most projects in view of the significantly reduced time for achieving a relatively high degree of consolidation. Resulting from an increase in trade activities at the Port of Brisbane, new facilities on Fisherman Islands at the mouth of the Brisbane River will be constructed on the new outer area (235 ha) adjacent to the existing port facilities through land reclamation. A vacuum-assisted surcharge load and conventional surcharge scheme in conjunction with prefabricated vertical drains was selected to reduce the required consolidation time through the deeper subsoil layers. The design of the combined vacuum and surcharge fill system and the construction of the embankment are described in this paper. A comparison of the performance of the vacuum combined surcharge loading system with a standard surcharge fill highlights the clear benefits of vacuum consolidation. Field monitoring data are presented to demonstrate how the embankment performed during construction. An analytical solution for radial consolidation considering both time-dependent surcharge loading and vacuum pressure is proposed to predict the settlements and associated excess pore pressures of the soft Holocene clay deposits. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1009_s1?isAuthorized=no
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1019-1027
Titre : Effect of GCL properties on shrinkage when subjected to wet-dry cycles Type de document : texte imprimé Auteurs : R. Kerry Rowe, Auteur ; L. E. Bostwick, Auteur ; W. A. Take, Auteur Année de publication : 2012 Article en page(s) : pp. 1019-1027 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : GCL Shrinkage Bentonite Résumé : The potential shrinkage of eight different geosynthetic clay liners (GCLs) subjected to wetting and drying cycles is examined. It is shown that the initial (e.g, off-the-roll) moisture content may affect the initial shrinkage but did not notably affect the final equilibrium shrinkage. For GCLs with granular bentonite and wetted to a moisture content of about 60% (or greater) in the hydration phase, the actual moisture content did not appear to affect the magnitude of the final equilibrium shrinkage. However, it did affect the rate of shrinkage. Specimens brought to about 100% moisture content in each cycle reached a constant shrinkage value much faster than those brought to about 60% in each wetting cycle. GCLs containing powdered bentonite generally shrank more than those containing granular bentonite. All of the powdered bentonite specimens continued a slow accumulation of strain with increasing cycles, even up to 75 cycles. The shrinkage of a needle-punched GCL with a thermally treated scrim-reinforced nonwoven carrier geotextile and granular bentonite was less than that for a needle-punched GCL with a simple nonwoven carrier and granular bentonite. For some products, there was considerable variability in GCL shrinkage for specimens from the same roll and tested under nominally identical conditions, whereas for other products, the variability was relatively small. The shrinkage strain required to cause the loss of a 150–300 mm panel overlap is shown to be able to be mobilized in about five wet-dry cycles in the experiments reported. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1019_s1?isAuthorized=no [article] Effect of GCL properties on shrinkage when subjected to wet-dry cycles [texte imprimé] / R. Kerry Rowe, Auteur ; L. E. Bostwick, Auteur ; W. A. Take, Auteur . - 2012 . - pp. 1019-1027.
Géotechnique
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1019-1027
Mots-clés : GCL Shrinkage Bentonite Résumé : The potential shrinkage of eight different geosynthetic clay liners (GCLs) subjected to wetting and drying cycles is examined. It is shown that the initial (e.g, off-the-roll) moisture content may affect the initial shrinkage but did not notably affect the final equilibrium shrinkage. For GCLs with granular bentonite and wetted to a moisture content of about 60% (or greater) in the hydration phase, the actual moisture content did not appear to affect the magnitude of the final equilibrium shrinkage. However, it did affect the rate of shrinkage. Specimens brought to about 100% moisture content in each cycle reached a constant shrinkage value much faster than those brought to about 60% in each wetting cycle. GCLs containing powdered bentonite generally shrank more than those containing granular bentonite. All of the powdered bentonite specimens continued a slow accumulation of strain with increasing cycles, even up to 75 cycles. The shrinkage of a needle-punched GCL with a thermally treated scrim-reinforced nonwoven carrier geotextile and granular bentonite was less than that for a needle-punched GCL with a simple nonwoven carrier and granular bentonite. For some products, there was considerable variability in GCL shrinkage for specimens from the same roll and tested under nominally identical conditions, whereas for other products, the variability was relatively small. The shrinkage strain required to cause the loss of a 150–300 mm panel overlap is shown to be able to be mobilized in about five wet-dry cycles in the experiments reported. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1019_s1?isAuthorized=no
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1028-1038
Titre : Water-retention behavior of geosynthetic clay liners Type de document : texte imprimé Auteurs : Ryley A. Beddoe, Auteur ; W. Andy Take, Auteur ; R. Kerry Rowe, Auteur Année de publication : 2012 Article en page(s) : pp. 1028-1038 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Clay liners Landfill Geosynthetics Unsaturated soils Résumé : The hydration and subsequent hydraulic performance of geosynthetic clay liners (GCLs) depend on the water-retention curve (WRC) of the GCL. Because of the inherent difficulty in obtaining the WRC for these materials, limited data exists regarding the WRCs of GCLs in the literature. In this study, high-capacity tensiometers and capacitance relative humidity sensors were used to quantify the water-retention behavior of GCLs for four different GCL products that vary both in materials (woven and nonwoven geotextiles) and in fabrication detail (thermal treatment and needle-punching). The water-retention behavior was investigated under wetting and drying paths; we present results in terms of gravimetric and volumetric moisture content and bulk GCL void ratio. The WRCs of the different GCL products showed significant variation among wetting and drying curves, indicating that both needle-punching and thermal treatment have a significant effect on the swelling behavior of the GCL and its WRC. Theoretical equations were fit to the experimental data, establishing the parameters that can be used for numerical modeling of these four GCL products. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1028_s1?isAuthorized=no [article] Water-retention behavior of geosynthetic clay liners [texte imprimé] / Ryley A. Beddoe, Auteur ; W. Andy Take, Auteur ; R. Kerry Rowe, Auteur . - 2012 . - pp. 1028-1038.
Géotechnique
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1028-1038
Mots-clés : Clay liners Landfill Geosynthetics Unsaturated soils Résumé : The hydration and subsequent hydraulic performance of geosynthetic clay liners (GCLs) depend on the water-retention curve (WRC) of the GCL. Because of the inherent difficulty in obtaining the WRC for these materials, limited data exists regarding the WRCs of GCLs in the literature. In this study, high-capacity tensiometers and capacitance relative humidity sensors were used to quantify the water-retention behavior of GCLs for four different GCL products that vary both in materials (woven and nonwoven geotextiles) and in fabrication detail (thermal treatment and needle-punching). The water-retention behavior was investigated under wetting and drying paths; we present results in terms of gravimetric and volumetric moisture content and bulk GCL void ratio. The WRCs of the different GCL products showed significant variation among wetting and drying curves, indicating that both needle-punching and thermal treatment have a significant effect on the swelling behavior of the GCL and its WRC. Theoretical equations were fit to the experimental data, establishing the parameters that can be used for numerical modeling of these four GCL products. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1028_s1?isAuthorized=no
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1039-1046
Titre : Quantification of volatile organic compounds diffusion for virgin geosynthetic clay liners and for a GCL after contact with a synthetic leachate Type de document : texte imprimé Auteurs : S. Paumier, Auteur ; N. Touze-Foltz, Auteur ; L. Mazeas, Auteur Année de publication : 2012 Article en page(s) : pp. 1039-1046 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Geosynthetic clay liners Volatile organic compounds Diffusion Cation exchange Laboratory Modelling Résumé : The effects on the nature of bentonite, natural sodium, and calcium activated, and of the cation exchange on the diffusive properties of two geosynthetic clay liners (GCLs) were examined. Diffusion laboratory tests were conducted to estimate the diffusion coefficients of 1, 2-dichloroethane (DCA), dichloromethane (DCM), thrichloroethylene (TCE), toluene, and benzene. Both GCLs were needle-punched and came from the same manufacturer. The nature of the bentonite contained in both GCLs was different because a natural sodium bentonite and a calcium activated sodium bentonite were tested. Furthermore, one of the GCLs experienced cation exchange from contact with a synthetic leachate used to generate an increase in its hydraulic conductivity by a factor of 8.5. The objective of this process was to evaluate if an increase in the hydraulic conductivity by cation exchange in a GCL would result in a significant increase in the diffusion coefficients of volatile organic compounds (VOCs). The results obtained for both virgin GCLs were very close to one another. No effect on the nature of the bentonite was observed. An increase in the diffusion coefficient was noticed for the case in which the GCL experienced cation exchange while in contact with a synthetic leachate for DCM, DCA, and TCE at a given bulk GCL void ratio. The largest increase, a factor of 2.6, was observed for TCE. However, this increase in the diffusion coefficient could have been balanced by the decrease in the bulk GCL void ratio from 3.9 to 3. The increase in the diffusion coefficient of VOCs, thus, does not seem to be of concern for the range of GCL hydraulic conductivities generated by cation exchange in this study. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1039_s1?isAuthorized=no [article] Quantification of volatile organic compounds diffusion for virgin geosynthetic clay liners and for a GCL after contact with a synthetic leachate [texte imprimé] / S. Paumier, Auteur ; N. Touze-Foltz, Auteur ; L. Mazeas, Auteur . - 2012 . - pp. 1039-1046.
Géotechnique
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1039-1046
Mots-clés : Geosynthetic clay liners Volatile organic compounds Diffusion Cation exchange Laboratory Modelling Résumé : The effects on the nature of bentonite, natural sodium, and calcium activated, and of the cation exchange on the diffusive properties of two geosynthetic clay liners (GCLs) were examined. Diffusion laboratory tests were conducted to estimate the diffusion coefficients of 1, 2-dichloroethane (DCA), dichloromethane (DCM), thrichloroethylene (TCE), toluene, and benzene. Both GCLs were needle-punched and came from the same manufacturer. The nature of the bentonite contained in both GCLs was different because a natural sodium bentonite and a calcium activated sodium bentonite were tested. Furthermore, one of the GCLs experienced cation exchange from contact with a synthetic leachate used to generate an increase in its hydraulic conductivity by a factor of 8.5. The objective of this process was to evaluate if an increase in the hydraulic conductivity by cation exchange in a GCL would result in a significant increase in the diffusion coefficients of volatile organic compounds (VOCs). The results obtained for both virgin GCLs were very close to one another. No effect on the nature of the bentonite was observed. An increase in the diffusion coefficient was noticed for the case in which the GCL experienced cation exchange while in contact with a synthetic leachate for DCM, DCA, and TCE at a given bulk GCL void ratio. The largest increase, a factor of 2.6, was observed for TCE. However, this increase in the diffusion coefficient could have been balanced by the decrease in the bulk GCL void ratio from 3.9 to 3. The increase in the diffusion coefficient of VOCs, thus, does not seem to be of concern for the range of GCL hydraulic conductivities generated by cation exchange in this study. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1039_s1?isAuthorized=no
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1047-1061
Titre : Prediction and interpretation of the performance of a deep excavation in Berlin sand Type de document : texte imprimé Auteurs : Maria A. Nikolinakou, Auteur ; Andrew J. Whittle, Auteur ; Stavros Savidis, Auteur Année de publication : 2012 Article en page(s) : pp. 1047-1061 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Constitutive model Deformation properties Finite element analysis Diaphragm wall Field instrumentation Résumé : This paper describes the application of a generalized effective stress soil model, MIT-S1, within a commercial finite-element program, for simulating the performance of the support system for the 20-m-deep excavation of the M1 pit adjacent to the primary station “Hauptbahnhof” in Berlin. The M1 pit was excavated underwater and supported by a perimeter diaphragm wall with a single row of prestressed anchors. Parameters for the soil model were derived from an extensive program of laboratory tests on the local Berlin sands. This calibration process highlights the practical difficulties both in the measurements of critical state soil properties and in the selection of model parameters. The predictions for excavation performance are strongly affected by the vertical profiles of two key state parameters: the initial earth pressure ratio, K0; and the in situ void ratio, e0. These parameters were estimated from field dynamic penetration test data and geological history. The results showed good agreement between computed and measured wall deflections and tieback forces for three instrumented sections. Much larger wall deflections were measured at a fourth section and may be attributable to the spatial variability in sand properties that was not considered in the current analyses. The results of this study highlight the importance of basic state parameter information for the successful application of advanced soil models. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1047_s1?isAuthorized=no [article] Prediction and interpretation of the performance of a deep excavation in Berlin sand [texte imprimé] / Maria A. Nikolinakou, Auteur ; Andrew J. Whittle, Auteur ; Stavros Savidis, Auteur . - 2012 . - pp. 1047-1061.
Géotechnique
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1047-1061
Mots-clés : Constitutive model Deformation properties Finite element analysis Diaphragm wall Field instrumentation Résumé : This paper describes the application of a generalized effective stress soil model, MIT-S1, within a commercial finite-element program, for simulating the performance of the support system for the 20-m-deep excavation of the M1 pit adjacent to the primary station “Hauptbahnhof” in Berlin. The M1 pit was excavated underwater and supported by a perimeter diaphragm wall with a single row of prestressed anchors. Parameters for the soil model were derived from an extensive program of laboratory tests on the local Berlin sands. This calibration process highlights the practical difficulties both in the measurements of critical state soil properties and in the selection of model parameters. The predictions for excavation performance are strongly affected by the vertical profiles of two key state parameters: the initial earth pressure ratio, K0; and the in situ void ratio, e0. These parameters were estimated from field dynamic penetration test data and geological history. The results showed good agreement between computed and measured wall deflections and tieback forces for three instrumented sections. Much larger wall deflections were measured at a fourth section and may be attributable to the spatial variability in sand properties that was not considered in the current analyses. The results of this study highlight the importance of basic state parameter information for the successful application of advanced soil models. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1047_s1?isAuthorized=no
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1062-1074
Titre : Energy conservation as a principle underlying mobilizable strength design for deep excavations Type de document : texte imprimé Auteurs : S. Y. Lam, Auteur ; M. D. Bolton, Auteur Année de publication : 2012 Article en page(s) : pp. 1062-1074 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Mobilizable strength design Case histories Deep excavation Soil stiffness Résumé : Finite-element analyses (FEA) and case histories of deep excavations in soft clay are used to validate a decision-making tool based on an extended mobilizable strength design (MSD) method that permits the designer an extremely simple method of predicting ground displacements during an undrained excavation. This newly extended MSD approach accommodates a number of issues that are important in underground construction between in situ walls, including alternative base heave mechanisms suitable either for wide excavations in relatively shallow soft clay strata or narrow excavations in relatively deep soft strata, the influence of support system stiffness in relation to the sequence of propping of the wall, and the capability of dealing with stratified ground. In addition, a simplified MSD framework is proposed for analyzing a database of 110 deep excavation case histories worldwide. The approach examines the governing factors controlling deformation in deep excavations and offers simple guidelines for designing support structures for deep excavations. These developments should make it possible for a design engineer to make informed decisions on the relationship between prop spacing and ground movements or the influence of wall stiffness and on the need for and influence of a jet-grouted base slab, for example, prior to conducting project-specific FEA. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1062_s1?isAuthorized=no [article] Energy conservation as a principle underlying mobilizable strength design for deep excavations [texte imprimé] / S. Y. Lam, Auteur ; M. D. Bolton, Auteur . - 2012 . - pp. 1062-1074.
Géotechnique
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1062-1074
Mots-clés : Mobilizable strength design Case histories Deep excavation Soil stiffness Résumé : Finite-element analyses (FEA) and case histories of deep excavations in soft clay are used to validate a decision-making tool based on an extended mobilizable strength design (MSD) method that permits the designer an extremely simple method of predicting ground displacements during an undrained excavation. This newly extended MSD approach accommodates a number of issues that are important in underground construction between in situ walls, including alternative base heave mechanisms suitable either for wide excavations in relatively shallow soft clay strata or narrow excavations in relatively deep soft strata, the influence of support system stiffness in relation to the sequence of propping of the wall, and the capability of dealing with stratified ground. In addition, a simplified MSD framework is proposed for analyzing a database of 110 deep excavation case histories worldwide. The approach examines the governing factors controlling deformation in deep excavations and offers simple guidelines for designing support structures for deep excavations. These developments should make it possible for a design engineer to make informed decisions on the relationship between prop spacing and ground movements or the influence of wall stiffness and on the need for and influence of a jet-grouted base slab, for example, prior to conducting project-specific FEA. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1062_s1?isAuthorized=no
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1075-1089
Titre : Validation of centrifuge model scaling for soil systems via trapdoor tests Type de document : texte imprimé Auteurs : Geraldo R. Iglesia, Auteur ; Herbert H. Einstein, Auteur ; Robert V. Whitman, Auteur Année de publication : 2012 Article en page(s) : pp. 1075-1089 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Centrifuge modeling Trapdoor tests Physical modeling Scaling laws Granular media Résumé : The validity of centrifuge modeling of soil systems is investigated by means of a “yielding trapdoor” setup similar to the one used by previous researchers for examining soil arching. A modeling-of-models exercise is thus carried out in accordance with centrifuge scaling requirements. This parametric study also includes the effects of g-level, grain-size, trapdoor width, and overburden depth. Particle-size scaling may be necessary to achieve full model-prototype similitude, depending on the structure-to-grain-size ratio. However, it appears that reasonable results can be achieved with centrifuge models, using the same soil as the prototype, where the structural dimensions are at least 20 times the grain size. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1075_s1?isAuthorized=no [article] Validation of centrifuge model scaling for soil systems via trapdoor tests [texte imprimé] / Geraldo R. Iglesia, Auteur ; Herbert H. Einstein, Auteur ; Robert V. Whitman, Auteur . - 2012 . - pp. 1075-1089.
Géotechnique
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1075-1089
Mots-clés : Centrifuge modeling Trapdoor tests Physical modeling Scaling laws Granular media Résumé : The validity of centrifuge modeling of soil systems is investigated by means of a “yielding trapdoor” setup similar to the one used by previous researchers for examining soil arching. A modeling-of-models exercise is thus carried out in accordance with centrifuge scaling requirements. This parametric study also includes the effects of g-level, grain-size, trapdoor width, and overburden depth. Particle-size scaling may be necessary to achieve full model-prototype similitude, depending on the structure-to-grain-size ratio. However, it appears that reasonable results can be achieved with centrifuge models, using the same soil as the prototype, where the structural dimensions are at least 20 times the grain size. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1075_s1?isAuthorized=no
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1090-1102
Titre : Shaft capacity of open-ended piles in clay Type de document : texte imprimé Auteurs : Paul Doherty, Auteur ; Kenneth Gavin, Auteur Année de publication : 2012 Article en page(s) : pp. 1090-1102 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Foundations Piles Open-ended penetration Radial stresses Instrumentation Résumé : This paper describes an experimental investigation designed to assess the impact of pile end condition on the capacity of piles installed in soft clay. A series of field tests are described in which instrumented open-ended and closed-ended model piles were jacked into soft clay. The radial stresses, pore pressures, and load distribution were recorded throughout installation, equalization, and load-testing. Although the total stress and pore pressure developed during installation were related to the degree of soil plugging, the radial effective stress that controls the shaft resistance was shown to be independent of the mode of penetration. The long-term shaft capacity of the open-ended pile was closely comparable to that developed by closed-ended piles, suggesting a limited influence of end condition on the fully equalized shaft resistance. In contrast to the shaft resistance, the base capacity was highly dependent on the degree of plugging. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1090_s1?isAuthorized=no [article] Shaft capacity of open-ended piles in clay [texte imprimé] / Paul Doherty, Auteur ; Kenneth Gavin, Auteur . - 2012 . - pp. 1090-1102.
Géotechnique
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1090-1102
Mots-clés : Foundations Piles Open-ended penetration Radial stresses Instrumentation Résumé : This paper describes an experimental investigation designed to assess the impact of pile end condition on the capacity of piles installed in soft clay. A series of field tests are described in which instrumented open-ended and closed-ended model piles were jacked into soft clay. The radial stresses, pore pressures, and load distribution were recorded throughout installation, equalization, and load-testing. Although the total stress and pore pressure developed during installation were related to the degree of soil plugging, the radial effective stress that controls the shaft resistance was shown to be independent of the mode of penetration. The long-term shaft capacity of the open-ended pile was closely comparable to that developed by closed-ended piles, suggesting a limited influence of end condition on the fully equalized shaft resistance. In contrast to the shaft resistance, the base capacity was highly dependent on the degree of plugging. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1090_s1?isAuthorized=no
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1103-1113
Titre : Modeling time-dependent behavior of soft sensitive clay Type de document : texte imprimé Auteurs : Minna Karstunen, Auteur ; Chang, Ching S., Auteur Année de publication : 2012 Article en page(s) : pp. 1103-1113 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Anisotropy Creep Destructuration Clay Time dependence Viscoplasticity Résumé : The paper focuses on investigating the destructuration process during time-dependent stress-strain evolution. For this purpose, various oedometer tests and triaxial tests on intact and reconstituted samples of soft sensitive Vanttila clay were carried out. Based on experimental observations, a new elastic viscoplastic model, extended from the overstress theory of Perzyna, is developed. The proposed model accounts for inherent and induced anisotropy, interparticle bonds and bond degradation, and viscosity. The determination of model parameters is discussed, demonstrating how all model parameters can be determined in a straightforward way and no additional test is needed for the proposed model compared to the modified Cam clay model. The model is implemented into a finite-element code, which enables coupled consolidation analyses. The model is used to simulate various strain-rate and creep tests under one-dimensional and triaxial conditions on the intact samples of Vanttila clay. The comparisons between experimental results and simulations show that the model has good predictive ability on the time-dependent behavior of a soft sensitive clay. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1103_s1?isAuthorized=no [article] Modeling time-dependent behavior of soft sensitive clay [texte imprimé] / Minna Karstunen, Auteur ; Chang, Ching S., Auteur . - 2012 . - pp. 1103-1113.
Géotechnique
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1103-1113
Mots-clés : Anisotropy Creep Destructuration Clay Time dependence Viscoplasticity Résumé : The paper focuses on investigating the destructuration process during time-dependent stress-strain evolution. For this purpose, various oedometer tests and triaxial tests on intact and reconstituted samples of soft sensitive Vanttila clay were carried out. Based on experimental observations, a new elastic viscoplastic model, extended from the overstress theory of Perzyna, is developed. The proposed model accounts for inherent and induced anisotropy, interparticle bonds and bond degradation, and viscosity. The determination of model parameters is discussed, demonstrating how all model parameters can be determined in a straightforward way and no additional test is needed for the proposed model compared to the modified Cam clay model. The model is implemented into a finite-element code, which enables coupled consolidation analyses. The model is used to simulate various strain-rate and creep tests under one-dimensional and triaxial conditions on the intact samples of Vanttila clay. The comparisons between experimental results and simulations show that the model has good predictive ability on the time-dependent behavior of a soft sensitive clay. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1103_s1?isAuthorized=no
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1114-1120
Titre : 3D analyses of open trench barriers filled with water Type de document : texte imprimé Auteurs : S. H. Ju, Auteur ; H. C. Li, Auteur Année de publication : 2012 Article en page(s) : pp. 1114-1120 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Experiment Finite-element analysis Open trench Soil Three-dimensional Water trench Wave Résumé : This study uses three-dimensional time-domain finite-element analyses to study the isolation efficiency of open trenches filled with various levels of water. The trench is generated along the X direction, the trench thickness is in the Y direction, and negative gravity is in the Z direction. First, the finite-element model is validated by using field experiments for a full water trench with results in good agreement. A parametric study from finite-element analyses indicates that the efficiency of the water trench is similar to or sometimes better than that of the open trench for X- and Z-direction waves. However, the water trench is not efficient for isolating the Y-direction wave, because the Y-direction wave passing through the water trench is similar to a compressive wave that is difficult to reduce in water. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1114_s1?isAuthorized=no [article] 3D analyses of open trench barriers filled with water [texte imprimé] / S. H. Ju, Auteur ; H. C. Li, Auteur . - 2012 . - pp. 1114-1120.
Géotechnique
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1114-1120
Mots-clés : Experiment Finite-element analysis Open trench Soil Three-dimensional Water trench Wave Résumé : This study uses three-dimensional time-domain finite-element analyses to study the isolation efficiency of open trenches filled with various levels of water. The trench is generated along the X direction, the trench thickness is in the Y direction, and negative gravity is in the Z direction. First, the finite-element model is validated by using field experiments for a full water trench with results in good agreement. A parametric study from finite-element analyses indicates that the efficiency of the water trench is similar to or sometimes better than that of the open trench for X- and Z-direction waves. However, the water trench is not efficient for isolating the Y-direction wave, because the Y-direction wave passing through the water trench is similar to a compressive wave that is difficult to reduce in water. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1114_s1?isAuthorized=no
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1121-1125
Titre : Experimental study of the earth pressure distribution on cylindrical shafts Type de document : texte imprimé Auteurs : Tatiana Tobar, Auteur ; Mohamed A. Meguid, Auteur Année de publication : 2012 Article en page(s) : pp. 1121-1125 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Vertical shafts Soft ground Axisymmetric earth pressure Physical models Cylindrical retaining walls Résumé : This paper describes the results from an experimental program that has been conducted to investigate the distribution of earth pressure on a cylindrical wall embedded in granular material and subjected to radial displacement. The model shaft has been designed and built using mechanically adjustable segments to control the magnitude and uniformity of the wall movement during the tests. A series of experiments have been performed, and the progressive changes in earth pressure along the shaft have been continuously measured for different wall displacements. Results indicated a rapid decrease in lateral earth pressure when a small wall movement was introduced. When the wall movement reached about 2.5% of the shaft radius, the earth pressure distribution along the shaft became uniform and independent of any additional wall displacement. The experimental results are also compared with some of the available theoretical solutions, and the applicability of these solutions is then examined. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1121_s1?isAuthorized=no [article] Experimental study of the earth pressure distribution on cylindrical shafts [texte imprimé] / Tatiana Tobar, Auteur ; Mohamed A. Meguid, Auteur . - 2012 . - pp. 1121-1125.
Géotechnique
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1121-1125
Mots-clés : Vertical shafts Soft ground Axisymmetric earth pressure Physical models Cylindrical retaining walls Résumé : This paper describes the results from an experimental program that has been conducted to investigate the distribution of earth pressure on a cylindrical wall embedded in granular material and subjected to radial displacement. The model shaft has been designed and built using mechanically adjustable segments to control the magnitude and uniformity of the wall movement during the tests. A series of experiments have been performed, and the progressive changes in earth pressure along the shaft have been continuously measured for different wall displacements. Results indicated a rapid decrease in lateral earth pressure when a small wall movement was introduced. When the wall movement reached about 2.5% of the shaft radius, the earth pressure distribution along the shaft became uniform and independent of any additional wall displacement. The experimental results are also compared with some of the available theoretical solutions, and the applicability of these solutions is then examined. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1121_s1?isAuthorized=no
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1126-1131
Titre : Voids/cement ratio controlling tensile strength of cement-treated soils Type de document : texte imprimé Auteurs : Nilo Cesar Consoli, Auteur ; António Viana Da Fonseca, Auteur Année de publication : 2012 Article en page(s) : pp. 1126-1131 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Cemented soil Porosity Tensile strength Compacted soils Voids/cement ratio Résumé : The improvement of locally available soils with cement can provide great advantages, including avoiding the need to borrow volumes of appropriate material and disposing of the local soil in deposits. This research aims to quantify the influence of the amount of cement, the porosity, and the voids/cement ratio in the assessment of splitting tensile strength (qt), also known as indirect diametrical tensile (IDT) strength, of three distinct soils from Brazil and Portugal. From Brazil, clayey sand derived from Botucatu sandstone and uniform Osorio sand were considered; from Portugal, silty sand derived from weathered Porto granite was studied. A number of splitting tensile strength tests were carried out. The results show that qt increased with the amount of cement (C) and decreases in porosity (η) for the three soil-cement mixtures. A power function was well-adapted to fit both qt-C and qt-η. Finally, the tensile strength was plotted against the porosity/volumetric cement content relationship (η/Civ), in which volumetric cement content is adjusted by a different exponent depending on the soil (0.21 for Porto silty sand-cement mixtures, 0.28 for Botucatu clayey sand-cement mixtures, and 1.0 for Osorio sand-cement mixtures). These plots show unique correlations for each soil-cement mixture, indicating that the index property is a good parameter in the evaluation of the splitting tensile strength of the soils studied. As a consequence, for each of the three soil-cement mixtures studied, a target qt value could be obtained by both porosity reduction and cement increase. This experimental framework will enable a good definition of the mechanical parameters used in the design of foundations and subgrades of railways platforms, whose system failure mechanisms usually start under tensile stresses at the base of the improved layer, and in the execution quality control of such earthworks. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1126_s1?isAuthorized=no [article] Voids/cement ratio controlling tensile strength of cement-treated soils [texte imprimé] / Nilo Cesar Consoli, Auteur ; António Viana Da Fonseca, Auteur . - 2012 . - pp. 1126-1131.
Géotechnique
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 11 (Novembre 2011) . - pp. 1126-1131
Mots-clés : Cemented soil Porosity Tensile strength Compacted soils Voids/cement ratio Résumé : The improvement of locally available soils with cement can provide great advantages, including avoiding the need to borrow volumes of appropriate material and disposing of the local soil in deposits. This research aims to quantify the influence of the amount of cement, the porosity, and the voids/cement ratio in the assessment of splitting tensile strength (qt), also known as indirect diametrical tensile (IDT) strength, of three distinct soils from Brazil and Portugal. From Brazil, clayey sand derived from Botucatu sandstone and uniform Osorio sand were considered; from Portugal, silty sand derived from weathered Porto granite was studied. A number of splitting tensile strength tests were carried out. The results show that qt increased with the amount of cement (C) and decreases in porosity (η) for the three soil-cement mixtures. A power function was well-adapted to fit both qt-C and qt-η. Finally, the tensile strength was plotted against the porosity/volumetric cement content relationship (η/Civ), in which volumetric cement content is adjusted by a different exponent depending on the soil (0.21 for Porto silty sand-cement mixtures, 0.28 for Botucatu clayey sand-cement mixtures, and 1.0 for Osorio sand-cement mixtures). These plots show unique correlations for each soil-cement mixture, indicating that the index property is a good parameter in the evaluation of the splitting tensile strength of the soils studied. As a consequence, for each of the three soil-cement mixtures studied, a target qt value could be obtained by both porosity reduction and cement increase. This experimental framework will enable a good definition of the mechanical parameters used in the design of foundations and subgrades of railways platforms, whose system failure mechanisms usually start under tensile stresses at the base of the improved layer, and in the execution quality control of such earthworks. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i11/p1126_s1?isAuthorized=no
Exemplaires
| Code-barres | Cote | Support | Localisation | Section | Disponibilité |
|---|---|---|---|---|---|
| aucun exemplaire | |||||
