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Ajouter le résultat dans votre panierAnalyzing liquefaction-induced lateral spreads using strength ratios / Scott M. Olson in Journal of geotechnical and geoenvironmental engineering, Vol. 134 n°8 (Août 2008)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1035–1049
Titre : Analyzing liquefaction-induced lateral spreads using strength ratios Type de document : texte imprimé Auteurs : Scott M. Olson, Auteur ; Cora I. Johnson, Auteur Année de publication : 2008 Article en page(s) : pp. 1035–1049 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Liquefaction Shear strength Penetration resistance In situ tests Earthquakes Lateral displacement Résumé : The writers backanalyzed 39 well-documented liquefaction-induced lateral spreads in terms of a mobilized strength ratio, su(mob)∕σ′vo using the Newmark sliding block method. Based on the inverse analyses results, we found that the backcalculated strength ratios mobilized during lateral spreads can be directly correlated to normalized cone penetration test tip resistance and standard penetration test blow count. Remarkably, Newmark analysis-based strength ratios mobilized during these lateral spreads essentially coincide with liquefied strength ratios backcalculated from liquefaction flow failures. The mobilized strength ratios appear to be independent of the magnitude of lateral displacement (at least for displacements greater than 15cm ) and the strength of shaking (in terms of peak ground acceleration). Furthermore, the mobilized strength ratios backcalculated from these cases appear to be consistent for a given depositional environment and do not appear to be severely impacted by potential water layer formation. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2810 [...] [article] Analyzing liquefaction-induced lateral spreads using strength ratios [texte imprimé] / Scott M. Olson, Auteur ; Cora I. Johnson, Auteur . - 2008 . - pp. 1035–1049.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1035–1049
Mots-clés : Liquefaction Shear strength Penetration resistance In situ tests Earthquakes Lateral displacement Résumé : The writers backanalyzed 39 well-documented liquefaction-induced lateral spreads in terms of a mobilized strength ratio, su(mob)∕σ′vo using the Newmark sliding block method. Based on the inverse analyses results, we found that the backcalculated strength ratios mobilized during lateral spreads can be directly correlated to normalized cone penetration test tip resistance and standard penetration test blow count. Remarkably, Newmark analysis-based strength ratios mobilized during these lateral spreads essentially coincide with liquefied strength ratios backcalculated from liquefaction flow failures. The mobilized strength ratios appear to be independent of the magnitude of lateral displacement (at least for displacements greater than 15cm ) and the strength of shaking (in terms of peak ground acceleration). Furthermore, the mobilized strength ratios backcalculated from these cases appear to be consistent for a given depositional environment and do not appear to be severely impacted by potential water layer formation. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2810 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1050–1058
Titre : Simplified procedure for developing joint distribution of amax and Mw for probabilistic liquefaction hazard analysis Type de document : texte imprimé Auteurs : C. Hsein Juang, Auteur ; David Kun Li, Auteur ; Sunny Ye Fang, Auteur Année de publication : 2008 Article en page(s) : pp. 1050–1058 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Ground motion Liquefaction Hazards Probability Résumé : This paper presents an innovative approach for a probabilistic analysis of liquefaction hazard at a given site in a specified exposure time based on the U.S. Geological Survey (USGS) National Seismic Hazard Maps data. The foundation of this new approach is a simplified procedure for obtaining a joint distribution of peak ground surface acceleration (amax) and moment magnitude of earthquake (Mw) at any given locality in the United States based on the USGS website data. The developed joint probability distribution of amax and Mw can be readily combined with the conditional probability of liquefaction (given a pair of amax and Mw ) to obtain the total probability of liquefaction at a given site in a specified exposure time. Detailed formulation of the new approach is presented and demonstrated with examples. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2810 [...] [article] Simplified procedure for developing joint distribution of amax and Mw for probabilistic liquefaction hazard analysis [texte imprimé] / C. Hsein Juang, Auteur ; David Kun Li, Auteur ; Sunny Ye Fang, Auteur . - 2008 . - pp. 1050–1058.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1050–1058
Mots-clés : Ground motion Liquefaction Hazards Probability Résumé : This paper presents an innovative approach for a probabilistic analysis of liquefaction hazard at a given site in a specified exposure time based on the U.S. Geological Survey (USGS) National Seismic Hazard Maps data. The foundation of this new approach is a simplified procedure for obtaining a joint distribution of peak ground surface acceleration (amax) and moment magnitude of earthquake (Mw) at any given locality in the United States based on the USGS website data. The developed joint probability distribution of amax and Mw can be readily combined with the conditional probability of liquefaction (given a pair of amax and Mw ) to obtain the total probability of liquefaction at a given site in a specified exposure time. Detailed formulation of the new approach is presented and demonstrated with examples. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2810 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1059–1072
Titre : Liquefaction and deformation analyses using a total stress approach Type de document : texte imprimé Auteurs : Michael H. Beaty, Auteur ; Peter M. Byrne, Auteur Année de publication : 2008 Article en page(s) : pp. 1059–1072 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Liquefaction Deformation Stress Seismic effects Dams Embankment Finite difference method Hydraulic fill Residual strength Résumé : Estimating deformations due to seismically induced liquefaction is often accomplished with a series of simplified uncoupled analyses. An alternative approach is presented in this paper that builds upon this common practice while making significant improvements to the modeling quality. A two-dimensional finite-difference analysis is performed in the time domain using a simple plasticity-based constitutive model. The triggering of liquefaction is assessed in each element by continuously weighting the cyclic shear stress history. Liquefaction is initially predicted in the most susceptible elements and then progressively spreads as the earthquake continues. The properties of liquefied elements are adjusted at the instant of liquefaction to reflect the anticipated loss of strength and stiffness. Dynamic equilibrium is always maintained so that computed deformations are rationally affected by the structural response, progressing liquefaction, and gravity forces. The method is demonstrated through application to the Upper San Fernando Dam and its response to the San Fernando earthquake of 1971. The objective of this approach is to achieve a practical balance between a rigorous numerical and theoretical analysis and currently accepted practice. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2810 [...] [article] Liquefaction and deformation analyses using a total stress approach [texte imprimé] / Michael H. Beaty, Auteur ; Peter M. Byrne, Auteur . - 2008 . - pp. 1059–1072.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1059–1072
Mots-clés : Liquefaction Deformation Stress Seismic effects Dams Embankment Finite difference method Hydraulic fill Residual strength Résumé : Estimating deformations due to seismically induced liquefaction is often accomplished with a series of simplified uncoupled analyses. An alternative approach is presented in this paper that builds upon this common practice while making significant improvements to the modeling quality. A two-dimensional finite-difference analysis is performed in the time domain using a simple plasticity-based constitutive model. The triggering of liquefaction is assessed in each element by continuously weighting the cyclic shear stress history. Liquefaction is initially predicted in the most susceptible elements and then progressively spreads as the earthquake continues. The properties of liquefied elements are adjusted at the instant of liquefaction to reflect the anticipated loss of strength and stiffness. Dynamic equilibrium is always maintained so that computed deformations are rationally affected by the structural response, progressing liquefaction, and gravity forces. The method is demonstrated through application to the Upper San Fernando Dam and its response to the San Fernando earthquake of 1971. The objective of this approach is to achieve a practical balance between a rigorous numerical and theoretical analysis and currently accepted practice. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2810 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1073–1085
Titre : Volumetric strains of clean sands subject to cyclic loads Type de document : texte imprimé Auteurs : Pendo M. Duku, Auteur ; Stewart, Jonathan P., Auteur ; Daniel H. Whang, Auteur Année de publication : 2008 Article en page(s) : pp. 1073–1085 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Seismic effects Compression Volume change Sand Résumé : We utilize simple shear testing to investigate the volume change of clean sands subject to cyclic loads. We examine the effects of a number of compositional and environmental factors on the vertical strain at 15 uniform shear strain cycles and on the cycle-to-cycle variation of vertical strain. The compositional factor found to principally affect seismic compression susceptibility is relative density. Compositional factors found to not significantly affect cyclic volume change include gradation parameters (mean grain size and uniformity coefficient), particle angularity, soil fabric, mineralogy, and void ratio “breadth” e-emin . An environmental factor found to affect seismic compression susceptibility is confining stress, with volumetric strains decreasing with increasing stress. Environmental factors that do not significantly affect seismic compression susceptibility for clean sands are saturation and age. Stress history can decrease vertical strains from seismic compression for certain conditions, but we find such effects to be insignificant for the levels of overburden stress where compacted fills are typically overconsolidated from compaction-induced stresses. An empirical model is developed to represent the major trends of the data for application in engineering practice, which improves upon an earlier model that is based on a much smaller database and does not account for the aforementioned environmental factors. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2810 [...] [article] Volumetric strains of clean sands subject to cyclic loads [texte imprimé] / Pendo M. Duku, Auteur ; Stewart, Jonathan P., Auteur ; Daniel H. Whang, Auteur . - 2008 . - pp. 1073–1085.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1073–1085
Mots-clés : Seismic effects Compression Volume change Sand Résumé : We utilize simple shear testing to investigate the volume change of clean sands subject to cyclic loads. We examine the effects of a number of compositional and environmental factors on the vertical strain at 15 uniform shear strain cycles and on the cycle-to-cycle variation of vertical strain. The compositional factor found to principally affect seismic compression susceptibility is relative density. Compositional factors found to not significantly affect cyclic volume change include gradation parameters (mean grain size and uniformity coefficient), particle angularity, soil fabric, mineralogy, and void ratio “breadth” e-emin . An environmental factor found to affect seismic compression susceptibility is confining stress, with volumetric strains decreasing with increasing stress. Environmental factors that do not significantly affect seismic compression susceptibility for clean sands are saturation and age. Stress history can decrease vertical strains from seismic compression for certain conditions, but we find such effects to be insignificant for the levels of overburden stress where compacted fills are typically overconsolidated from compaction-induced stresses. An empirical model is developed to represent the major trends of the data for application in engineering practice, which improves upon an earlier model that is based on a much smaller database and does not account for the aforementioned environmental factors. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2810 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1086–1096
Titre : Dynamic centrifuge testing of slickensided shear surfaces Type de document : texte imprimé Auteurs : Christopher L. Meehan, Auteur ; Ross W. Boulanger, Auteur ; J. Michael Duncan, Auteur Année de publication : 2008 Article en page(s) : pp. 1086–1096 Note générale : Geotechnical and geotechnical engineering Langues : Anglais (eng) Mots-clés : Dynamic stability Clays Residual strength Slope stability Earthquakes Soil deformation Shear strength Overconsolidated soils Centrifuge Résumé : Movement along preexisting slickensided rupture surfaces in overconsolidated clay and clay shale slopes can represent a critical sliding mechanism during earthquakes. The seismic behavior of preexisting slickensided surfaces in overconsolidated clay was examined by performing dynamic centrifuge model tests of two slickensided sliding block models constructed using Rancho Solano lean clay. Dynamic shear displacements were concentrated along the preformed slickensided surfaces. The peak shear resistances mobilized along the slickensided surfaces during dynamic loading were 90–120% higher than the drained residual strength measured prior to shaking. To accurately predict the displacements of the sliding blocks using Newmark’s method, it was necessary to use dynamic strengths that were 37–64% larger than the drained residual strength of the soil. Dynamic loading caused a positive pore pressure response in the soil surrounding the slickensided planes. The postshaking shear strengths were 17–31% higher than those measured prior to shaking. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2810 [...] [article] Dynamic centrifuge testing of slickensided shear surfaces [texte imprimé] / Christopher L. Meehan, Auteur ; Ross W. Boulanger, Auteur ; J. Michael Duncan, Auteur . - 2008 . - pp. 1086–1096.
Geotechnical and geotechnical engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1086–1096
Mots-clés : Dynamic stability Clays Residual strength Slope stability Earthquakes Soil deformation Shear strength Overconsolidated soils Centrifuge Résumé : Movement along preexisting slickensided rupture surfaces in overconsolidated clay and clay shale slopes can represent a critical sliding mechanism during earthquakes. The seismic behavior of preexisting slickensided surfaces in overconsolidated clay was examined by performing dynamic centrifuge model tests of two slickensided sliding block models constructed using Rancho Solano lean clay. Dynamic shear displacements were concentrated along the preformed slickensided surfaces. The peak shear resistances mobilized along the slickensided surfaces during dynamic loading were 90–120% higher than the drained residual strength measured prior to shaking. To accurately predict the displacements of the sliding blocks using Newmark’s method, it was necessary to use dynamic strengths that were 37–64% larger than the drained residual strength of the soil. Dynamic loading caused a positive pore pressure response in the soil surrounding the slickensided planes. The postshaking shear strengths were 17–31% higher than those measured prior to shaking. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2810 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1097–1105
Titre : Economic design optimization of foundations Type de document : texte imprimé Auteurs : Yu Wang, Auteur ; Fred H. Kulhawy, Auteur Année de publication : 2008 Article en page(s) : pp. 1097–1105 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Economic factors Cost estimates Optimization Spread foundations Limit states Serviceability Résumé : A geotechnical foundation design should address at least three basic requirements: ultimate limit state (ULS), serviceability limit state (SLS), and economics. Most conventional design approaches focus on ULS and/or SLS optimization, with economics being evaluated afterwards. As an alternative, this paper develops a design approach that explicitly considers the construction economics and results in a foundation that has the minimum construction cost. This design approach is expressed as an optimization process, in which the objective is to minimize construction cost, with the design parameters and design requirements as the optimization variables and constraints, respectively. This design approach is illustrated using a spread footing example. Because construction costs vary by locale, the economically optimized designs differ regionally. Sensitivity studies on soil properties and design requirements show that, for typical spread footing designs in cohesionless soils, Young’s modulus (E) and the effective friction angle (ϕ′) are the key parameters. A quantitative assessment illustrates the importance of soil property variability on cost. It is also found that, for typical spread footing designs, a relatively stringent ULS requirement generally ensures fulfillment of the SLS requirement. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2810 [...] [article] Economic design optimization of foundations [texte imprimé] / Yu Wang, Auteur ; Fred H. Kulhawy, Auteur . - 2008 . - pp. 1097–1105.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1097–1105
Mots-clés : Economic factors Cost estimates Optimization Spread foundations Limit states Serviceability Résumé : A geotechnical foundation design should address at least three basic requirements: ultimate limit state (ULS), serviceability limit state (SLS), and economics. Most conventional design approaches focus on ULS and/or SLS optimization, with economics being evaluated afterwards. As an alternative, this paper develops a design approach that explicitly considers the construction economics and results in a foundation that has the minimum construction cost. This design approach is expressed as an optimization process, in which the objective is to minimize construction cost, with the design parameters and design requirements as the optimization variables and constraints, respectively. This design approach is illustrated using a spread footing example. Because construction costs vary by locale, the economically optimized designs differ regionally. Sensitivity studies on soil properties and design requirements show that, for typical spread footing designs in cohesionless soils, Young’s modulus (E) and the effective friction angle (ϕ′) are the key parameters. A quantitative assessment illustrates the importance of soil property variability on cost. It is also found that, for typical spread footing designs, a relatively stringent ULS requirement generally ensures fulfillment of the SLS requirement. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2810 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1106–1117
Titre : Load resistance factor design of axially loaded pile based on load test results Type de document : texte imprimé Auteurs : Sumanta Haldar, Auteur ; G. L. Sivakumar Babu, Auteur Année de publication : 2008 Article en page(s) : pp. 1106–1117 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Load and resistance factor design Monte Carlo method Pile load tests Reliability Ultimate loads Piles Axial loads Load tests Résumé : The present study proposes a procedure to determine partial factors in reliability based design format for pile foundations, considering bias as well as uncertainty in the parameters that represent soil-pile interaction. These issues are addressed using pile load-settlement test data from case studies obtained from the literature. The pile ultimate capacities are evaluated considering three different failure criteria. The uncertainties in the pile-soil interface parameters as well as pile ultimate capacity are quantified in Monte Carlo framework from the measured data by utilizing the closed form “ t-z ” method. Considering dead load to live load ratios as calibration points, the target reliability index is calculated based on existing code safety-checking format. The optimal partial factors are determined such that the difference between reliability index based on limit state equations expressed in terms of partial factors and target reliability index is minimum. Finally, it is observed that optimal partial factors enable rational choice of allowable load on pile foundation. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2811 [...] [article] Load resistance factor design of axially loaded pile based on load test results [texte imprimé] / Sumanta Haldar, Auteur ; G. L. Sivakumar Babu, Auteur . - 2008 . - pp. 1106–1117.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1106–1117
Mots-clés : Load and resistance factor design Monte Carlo method Pile load tests Reliability Ultimate loads Piles Axial loads Load tests Résumé : The present study proposes a procedure to determine partial factors in reliability based design format for pile foundations, considering bias as well as uncertainty in the parameters that represent soil-pile interaction. These issues are addressed using pile load-settlement test data from case studies obtained from the literature. The pile ultimate capacities are evaluated considering three different failure criteria. The uncertainties in the pile-soil interface parameters as well as pile ultimate capacity are quantified in Monte Carlo framework from the measured data by utilizing the closed form “ t-z ” method. Considering dead load to live load ratios as calibration points, the target reliability index is calculated based on existing code safety-checking format. The optimal partial factors are determined such that the difference between reliability index based on limit state equations expressed in terms of partial factors and target reliability index is minimum. Finally, it is observed that optimal partial factors enable rational choice of allowable load on pile foundation. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2811 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1118–1128
Titre : Analysis and performance of piled rafts designed using innovative criteria Type de document : texte imprimé Auteurs : Luca de Sanctis, Auteur ; Gianpiero Russo, Auteur Année de publication : 2008 Article en page(s) : pp. 1118–1128 Note générale : Geotecnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Raft foundations Pile foundations Foundation design Foundation settlement Résumé : In this paper the main criteria adopted for the design and some aspects of the observed behavior of the piled foundations of a cluster of circular steel tanks are reported. They were designed to store sodium hydroxide, a toxic liquid with a unit weight of 15.1kN/m3 . Shallow foundations would have been safe against a bearing capacity failure, while the predicted settlement was beyond the allowed limit. Accordingly piles were designed to reduce the settlement and improve the overall performance of the foundations. While conventional capacity based design approach led to a total of 160 piles to support the five tanks the settlement based design approach led to a total of 65 piles achieving significant savings on the cost of the project. The settlements of four out of the five tanks were measured and for two out of the five tanks the load sharing among the raft and the piles was also observed. Both the analyses carried out at the design stage and the back-analyses of the observed behavior were based on the interaction factors method as implemented in the computer code NAPRA [Russo (1998), Int. J. Numer. Anal. Methods Geomech., 22(6), 477–493]. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2811 [...] [article] Analysis and performance of piled rafts designed using innovative criteria [texte imprimé] / Luca de Sanctis, Auteur ; Gianpiero Russo, Auteur . - 2008 . - pp. 1118–1128.
Geotecnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1118–1128
Mots-clés : Raft foundations Pile foundations Foundation design Foundation settlement Résumé : In this paper the main criteria adopted for the design and some aspects of the observed behavior of the piled foundations of a cluster of circular steel tanks are reported. They were designed to store sodium hydroxide, a toxic liquid with a unit weight of 15.1kN/m3 . Shallow foundations would have been safe against a bearing capacity failure, while the predicted settlement was beyond the allowed limit. Accordingly piles were designed to reduce the settlement and improve the overall performance of the foundations. While conventional capacity based design approach led to a total of 160 piles to support the five tanks the settlement based design approach led to a total of 65 piles achieving significant savings on the cost of the project. The settlements of four out of the five tanks were measured and for two out of the five tanks the load sharing among the raft and the piles was also observed. Both the analyses carried out at the design stage and the back-analyses of the observed behavior were based on the interaction factors method as implemented in the computer code NAPRA [Russo (1998), Int. J. Numer. Anal. Methods Geomech., 22(6), 477–493]. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2811 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1129–1141
Titre : Capacity, settlement, and energy dissipation of shallow footings subjected to rocking Type de document : texte imprimé Auteurs : Sivapalan Gajan, Auteur ; Kutter, Bruce L., Auteur Année de publication : 2008 Article en page(s) : pp. 1129–1141 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Settlement Energy Dissipation Footings Shallow foundations Seismic loads Résumé : The effectiveness of structural fuse mechanisms used to improve the performance of buildings during seismic loading depends on their capacity, ductility, energy dissipation, isolation, and self-centering characteristics. Although rocking shallow footings could also be designed to possess many of these desirable characteristics, current civil engineering practice often avoids nonlinear behavior of soil in design, due to the lack of confidence and knowledge about cyclic rocking. Several centrifuge experiments were conducted to study the rocking behavior of shallow footings, supported by sand and clay soil stratums, during slow lateral cyclic loading and dynamic shaking. The ratio of the footing area to the footing contact area required to support the applied vertical loads (A∕Ac) , related to the factor of safety with respect to vertical loading, is correlated with moment capacity, energy dissipation, and permanent settlement measured in centrifuge and 1 g model tests. Results show that a footing with large A∕Ac ratio (about 10) possesses a moment capacity that is insensitive to soil properties, does not suffer large permanent settlements, has a self-centering characteristic associated with uplift and gap closure, and dissipates seismic energy that corresponds to about 20% damping ratio. Thus, there is promise to use rocking footings in place of, or in combination with, structural base isolation and energy dissipation devices to improve the performance of the structure during seismic loading. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2811 [...] [article] Capacity, settlement, and energy dissipation of shallow footings subjected to rocking [texte imprimé] / Sivapalan Gajan, Auteur ; Kutter, Bruce L., Auteur . - 2008 . - pp. 1129–1141.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1129–1141
Mots-clés : Settlement Energy Dissipation Footings Shallow foundations Seismic loads Résumé : The effectiveness of structural fuse mechanisms used to improve the performance of buildings during seismic loading depends on their capacity, ductility, energy dissipation, isolation, and self-centering characteristics. Although rocking shallow footings could also be designed to possess many of these desirable characteristics, current civil engineering practice often avoids nonlinear behavior of soil in design, due to the lack of confidence and knowledge about cyclic rocking. Several centrifuge experiments were conducted to study the rocking behavior of shallow footings, supported by sand and clay soil stratums, during slow lateral cyclic loading and dynamic shaking. The ratio of the footing area to the footing contact area required to support the applied vertical loads (A∕Ac) , related to the factor of safety with respect to vertical loading, is correlated with moment capacity, energy dissipation, and permanent settlement measured in centrifuge and 1 g model tests. Results show that a footing with large A∕Ac ratio (about 10) possesses a moment capacity that is insensitive to soil properties, does not suffer large permanent settlements, has a self-centering characteristic associated with uplift and gap closure, and dissipates seismic energy that corresponds to about 20% damping ratio. Thus, there is promise to use rocking footings in place of, or in combination with, structural base isolation and energy dissipation devices to improve the performance of the structure during seismic loading. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2811 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1142–1153
Titre : Effect of penetration rate on cone penetration resistance in saturated clayey soils Type de document : texte imprimé Auteurs : Kwangkyun Kim, Auteur ; Monica Prezzi, Auteur ; Rodrigo Salgado, Auteur Année de publication : 2008 Article en page(s) : pp. 1142–1153 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Cone penetration tests Penetration resistance Clays Sand Résumé : In this paper, the effects of penetration rate on cone resistance in saturated clayey soils are investigated. Shear strength rate effects in clayey soils are related to two physical processes: the increase of shear strength with increasing rate of loading and the increase of shear strength as the process transitions from undrained to drained. Special focus is placed on this second effect. Cone penetration tests were performed at various penetration rates both in the field and in a calibration chamber, and the resulting data were analyzed. The field cone penetration tests were performed at two test sites with fairly homogeneous clayey silt and silty clay layers located below the groundwater table. Additionally, tests with both cone and flat-tip penetrometers in sand-clay mixtures were performed in a calibration chamber to investigate the change in drainage conditions from undrained to partially drained and from partially drained to fully drained. A series of flexible-wall permeameter tests were conducted in the laboratory for various clayey sand mixtures prepared at various mixing ratios in order to obtain values of the coefficient of consolidation, which is required to estimate the penetration rates below which penetration is drained and above which penetration is undrained. A correlation between cone resistance and drainage conditions was established based on the results of the calibration chamber and field penetration tests. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2811 [...] [article] Effect of penetration rate on cone penetration resistance in saturated clayey soils [texte imprimé] / Kwangkyun Kim, Auteur ; Monica Prezzi, Auteur ; Rodrigo Salgado, Auteur . - 2008 . - pp. 1142–1153.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1142–1153
Mots-clés : Cone penetration tests Penetration resistance Clays Sand Résumé : In this paper, the effects of penetration rate on cone resistance in saturated clayey soils are investigated. Shear strength rate effects in clayey soils are related to two physical processes: the increase of shear strength with increasing rate of loading and the increase of shear strength as the process transitions from undrained to drained. Special focus is placed on this second effect. Cone penetration tests were performed at various penetration rates both in the field and in a calibration chamber, and the resulting data were analyzed. The field cone penetration tests were performed at two test sites with fairly homogeneous clayey silt and silty clay layers located below the groundwater table. Additionally, tests with both cone and flat-tip penetrometers in sand-clay mixtures were performed in a calibration chamber to investigate the change in drainage conditions from undrained to partially drained and from partially drained to fully drained. A series of flexible-wall permeameter tests were conducted in the laboratory for various clayey sand mixtures prepared at various mixing ratios in order to obtain values of the coefficient of consolidation, which is required to estimate the penetration rates below which penetration is drained and above which penetration is undrained. A correlation between cone resistance and drainage conditions was established based on the results of the calibration chamber and field penetration tests. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2811 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1154–1165
Titre : Fast stacking and phase corrections of shear wave signals in a noisy environment Type de document : texte imprimé Auteurs : Scott J. Brandenberg, Auteur ; Kutter, Bruce L., Auteur ; Daniel W. Wilson, Auteur Année de publication : 2008 Article en page(s) : pp. 1154–1165 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Wave velocity Shear waves Soil modulus Soil-structure interaction Centrifuge Piezoelectricity Résumé : Hardware, software, and analysis of transient response of sources and receivers are presented for a piezoelectric bender element system designed to measure shear wave velocities in noisy environments. Signal-to-noise ratio is improved by signal stacking, wherein data vectors from many pulses are summed. A new fast-stacking algorithm enables signal quality to be improved much more rapidly than conventional stacking. Conventional stacking is accomplished by repeatedly sending an excitation pulse to a source, waiting for the signal and secondary reflections to pass the receiver and then introducing a subsequent excitation pulse. Using conventional stacking, it is important to wait for the signal and secondary reflections to die out before exciting subsequent pulses. In the new fast-stacking algorithm, a varied interval between consecutive pulses is used so that high quality signals can be obtained even if consecutive pulses are excited in rapid succession. Transient behavior of soil–bender interaction was characterized using closed-form analytical solutions of single-degree-of-freedom oscillators, numerical solutions using a beam-on-springs method, and measurements from an array of bender elements in a sand model. The time delay caused by soil–bender interaction was calculated to be half of the natural period of the bender element, and this theoretical time delay was supported by experimental data. This system makes it feasible to rapidly collect accurate shear wave velocity information so that transient changes in shear wave velocity can be monitored even if background noise is large. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2811 [...] [article] Fast stacking and phase corrections of shear wave signals in a noisy environment [texte imprimé] / Scott J. Brandenberg, Auteur ; Kutter, Bruce L., Auteur ; Daniel W. Wilson, Auteur . - 2008 . - pp. 1154–1165.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1154–1165
Mots-clés : Wave velocity Shear waves Soil modulus Soil-structure interaction Centrifuge Piezoelectricity Résumé : Hardware, software, and analysis of transient response of sources and receivers are presented for a piezoelectric bender element system designed to measure shear wave velocities in noisy environments. Signal-to-noise ratio is improved by signal stacking, wherein data vectors from many pulses are summed. A new fast-stacking algorithm enables signal quality to be improved much more rapidly than conventional stacking. Conventional stacking is accomplished by repeatedly sending an excitation pulse to a source, waiting for the signal and secondary reflections to pass the receiver and then introducing a subsequent excitation pulse. Using conventional stacking, it is important to wait for the signal and secondary reflections to die out before exciting subsequent pulses. In the new fast-stacking algorithm, a varied interval between consecutive pulses is used so that high quality signals can be obtained even if consecutive pulses are excited in rapid succession. Transient behavior of soil–bender interaction was characterized using closed-form analytical solutions of single-degree-of-freedom oscillators, numerical solutions using a beam-on-springs method, and measurements from an array of bender elements in a sand model. The time delay caused by soil–bender interaction was calculated to be half of the natural period of the bender element, and this theoretical time delay was supported by experimental data. This system makes it feasible to rapidly collect accurate shear wave velocity information so that transient changes in shear wave velocity can be monitored even if background noise is large. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2811 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1166–1180
Titre : Sepiolite as an alternative liner material in municipal solid waste landfills Type de document : texte imprimé Auteurs : Yucel Guney, Auteur ; Savas Koparal, Auteur ; Ahmet H. Aydilek, Auteur Année de publication : 2008 Article en page(s) : pp. 1166–1180 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Municipal wastes Solid wastes Landfills Adsorption Inorganic chemicals Waste management Résumé : Compacted clay has traditionally been used as a lining material in municipal solid waste landfills. However, natural clays may not always provide good contaminant sorption properties. One alternative material that is abundant in some parts of Europe and Turkey as well as Western United States is sepiolite. A laboratory study was undertaken to investigate the feasibility of sepiolite as a liner material. Two clays, one rich in sepiolite and the other one rich in kaolinite mineral, as well as their mixtures were subjected to geomechanical, hydraulic, and environmental tests. The same soils were also subjected to strength and hydraulic conductivity tests after a series of freeze and thaw cycles. The results of the study indicated that relatively high hydraulic conductivity and shrinkage capacity of sepiolite necessitates addition of kaolinite before being used as a landfill material. The valence of the salt solutions affected the swell and hydraulic conductivity characteristics of the clays tested. Retardation factors for sepiolite for metal solutions are 1.2–2.2 times higher than those calculated for the clay that is rich in kaolinite, and the inorganic contaminant adsorption capacity of the clay can be improved by addition of sepiolite. The results indicated that the clay mixtures utilized in this study provide good geomechanical, hydraulic, and metal adsorption properties which may justify their potential use as a liner material in solid waste landfills. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2811 [...] [article] Sepiolite as an alternative liner material in municipal solid waste landfills [texte imprimé] / Yucel Guney, Auteur ; Savas Koparal, Auteur ; Ahmet H. Aydilek, Auteur . - 2008 . - pp. 1166–1180.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1166–1180
Mots-clés : Municipal wastes Solid wastes Landfills Adsorption Inorganic chemicals Waste management Résumé : Compacted clay has traditionally been used as a lining material in municipal solid waste landfills. However, natural clays may not always provide good contaminant sorption properties. One alternative material that is abundant in some parts of Europe and Turkey as well as Western United States is sepiolite. A laboratory study was undertaken to investigate the feasibility of sepiolite as a liner material. Two clays, one rich in sepiolite and the other one rich in kaolinite mineral, as well as their mixtures were subjected to geomechanical, hydraulic, and environmental tests. The same soils were also subjected to strength and hydraulic conductivity tests after a series of freeze and thaw cycles. The results of the study indicated that relatively high hydraulic conductivity and shrinkage capacity of sepiolite necessitates addition of kaolinite before being used as a landfill material. The valence of the salt solutions affected the swell and hydraulic conductivity characteristics of the clays tested. Retardation factors for sepiolite for metal solutions are 1.2–2.2 times higher than those calculated for the clay that is rich in kaolinite, and the inorganic contaminant adsorption capacity of the clay can be improved by addition of sepiolite. The results indicated that the clay mixtures utilized in this study provide good geomechanical, hydraulic, and metal adsorption properties which may justify their potential use as a liner material in solid waste landfills. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2811 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1181–1191
Titre : Deeply buried thermoplastic pipe field performance over five years Type de document : texte imprimé Auteurs : Shad Sargand, Auteur ; Teruhisa Masada, Auteur ; Bashar Tarawneh, Auteur Année de publication : 2008 Article en page(s) : pp. 1181–1191 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Buried pipes Deflection Soil pressure Temperature Soil water Résumé : This paper presents the updated long-term field performance data from the thermoplastic pipe deep burial study that the writers first initiated in the summer of 1999. The data from the past four to five years are presented in terms of pipe deflections and soil pressure measured at the pipe crown. Examinations of the historic field performance data revealed pipe-soil interaction behavior that had not been reported previously. The long-term pipe performance of both polyvinyl chloride and high density polyethylene pipes installed under at least 6.1m (20ft) of soil fill was characterized with nearly constant deflections/circumferential shortening and fluctuating soil pressures. Review of the long-term soil pressure data revealed some interesting trends regarding the relationships among pipe material type, pipe wall design, and fill height. Detailed review of the soil pressure data also led to a reasonable speculation that the seasonal fluctuations of environmental (air temperature, soil moisture) conditions caused the fluctuations in the peripheral soil pressure. Theoretical analysis based on the full-field elastic solutions showed that the temperature most likely had a much larger influence on the soil pressure fluctuations than the changes in the soil moisture conditions. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2811 [...] [article] Deeply buried thermoplastic pipe field performance over five years [texte imprimé] / Shad Sargand, Auteur ; Teruhisa Masada, Auteur ; Bashar Tarawneh, Auteur . - 2008 . - pp. 1181–1191.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1181–1191
Mots-clés : Buried pipes Deflection Soil pressure Temperature Soil water Résumé : This paper presents the updated long-term field performance data from the thermoplastic pipe deep burial study that the writers first initiated in the summer of 1999. The data from the past four to five years are presented in terms of pipe deflections and soil pressure measured at the pipe crown. Examinations of the historic field performance data revealed pipe-soil interaction behavior that had not been reported previously. The long-term pipe performance of both polyvinyl chloride and high density polyethylene pipes installed under at least 6.1m (20ft) of soil fill was characterized with nearly constant deflections/circumferential shortening and fluctuating soil pressures. Review of the long-term soil pressure data revealed some interesting trends regarding the relationships among pipe material type, pipe wall design, and fill height. Detailed review of the soil pressure data also led to a reasonable speculation that the seasonal fluctuations of environmental (air temperature, soil moisture) conditions caused the fluctuations in the peripheral soil pressure. Theoretical analysis based on the full-field elastic solutions showed that the temperature most likely had a much larger influence on the soil pressure fluctuations than the changes in the soil moisture conditions. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2811 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1192–1200
Titre : Three-dimensional stability analysis of convex slopes in plan view Type de document : texte imprimé Auteurs : Farzaneh, Orang, Auteur ; Faradjollah Askari, Auteur ; Navid Ganjian, Auteur Année de publication : 2008 Article en page(s) : pp. 1192–1200 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Slope stability Limit analysis Algorithms Résumé : A method of three-dimensional slope stability analysis for convex slopes in plan view is presented here based on the upper-bound theorem of the limit analysis approach. The method can also be used to determine the bearing capacity of foundations adjacent to such slopes. A rigid-block translational collapse mechanism is considered in which energy dissipation takes place along planar velocity discontinuities. Comparing the bearing capacity of foundations, numerical results indicate that the one located near convex slopes has less capacity than the one located near straight slopes. Inversely, slopes not subjected to surcharge loads are more stable when they are convex. Concerning the bearing capacity analyses, consideration of the curvature effect of convex slopes is more significant in frictional soils whereas for slope stability analyses, mentioned effect is of prime importance in cohesive soils. Numerical results of proposed algorithm are presented in the form of nondimensional graphs. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2811 [...] [article] Three-dimensional stability analysis of convex slopes in plan view [texte imprimé] / Farzaneh, Orang, Auteur ; Faradjollah Askari, Auteur ; Navid Ganjian, Auteur . - 2008 . - pp. 1192–1200.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1192–1200
Mots-clés : Slope stability Limit analysis Algorithms Résumé : A method of three-dimensional slope stability analysis for convex slopes in plan view is presented here based on the upper-bound theorem of the limit analysis approach. The method can also be used to determine the bearing capacity of foundations adjacent to such slopes. A rigid-block translational collapse mechanism is considered in which energy dissipation takes place along planar velocity discontinuities. Comparing the bearing capacity of foundations, numerical results indicate that the one located near convex slopes has less capacity than the one located near straight slopes. Inversely, slopes not subjected to surcharge loads are more stable when they are convex. Concerning the bearing capacity analyses, consideration of the curvature effect of convex slopes is more significant in frictional soils whereas for slope stability analyses, mentioned effect is of prime importance in cohesive soils. Numerical results of proposed algorithm are presented in the form of nondimensional graphs. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2811 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1201–1204
Titre : Forensic investigation of pavement premature failure due to soil sulfate-induced heave Type de document : texte imprimé Auteurs : Zhiming Si, Auteur Année de publication : 2008 Article en page(s) : pp. 1201–1204 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Heaving Moisture Compressive strength Soil stabilization Forensic engineering Failures Résumé : Current practice does not recommend stabilizing high sulfate-bearing soils using calcium-based stabilizers due to high potential swell and low retained unconfined compressive strength. In this technical note, a series of tests has demonstrated that a combination of lime and fly ash (Class F) proved to be the most suitable stabilizer for a high sulfate-bearing soil, and a combination of lime and slag seemed to be the most effective stabilizer for a moderate sulfate-bearing soil in terms of retained unconfined compressive strength and three-dimensional free swell potential. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2812 [...] [article] Forensic investigation of pavement premature failure due to soil sulfate-induced heave [texte imprimé] / Zhiming Si, Auteur . - 2008 . - pp. 1201–1204.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1201–1204
Mots-clés : Heaving Moisture Compressive strength Soil stabilization Forensic engineering Failures Résumé : Current practice does not recommend stabilizing high sulfate-bearing soils using calcium-based stabilizers due to high potential swell and low retained unconfined compressive strength. In this technical note, a series of tests has demonstrated that a combination of lime and fly ash (Class F) proved to be the most suitable stabilizer for a high sulfate-bearing soil, and a combination of lime and slag seemed to be the most effective stabilizer for a moderate sulfate-bearing soil in terms of retained unconfined compressive strength and three-dimensional free swell potential. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2812 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1205–1209
Titre : Identifying consolidation coefficient : linear excess pore-water pressure Type de document : texte imprimé Auteurs : Singh, Sushil K., Auteur Année de publication : 2008 Article en page(s) : pp. 1205–1209 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Soil consolidation Pore water pressure Settlement Parameters Coefficients Résumé : Diagnostic curve methods are developed for simultaneously identifying consolidation coefficient, final settlement, and ratio of top and bottom excess pore-water pressures from observed settlements, in the case of linear excess pore-water pressure. Simple equations are also proposed for estimating consolidation coefficient and final settlement. The proposed methods and equations are applicable for any type of linear loading or drainage condition (one-way or two-way drainage). Solutions for pore-water pressure distribution and transient settlement of clay layers under linear loading of pore-water pressure with one-way drainage are also developed, which are used in the development of the methods. The proposed methods do not require full settlement data for the identification of parameters and the parameters can be identified from only initial but adequate settlement data. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2812 [...] [article] Identifying consolidation coefficient : linear excess pore-water pressure [texte imprimé] / Singh, Sushil K., Auteur . - 2008 . - pp. 1205–1209.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1205–1209
Mots-clés : Soil consolidation Pore water pressure Settlement Parameters Coefficients Résumé : Diagnostic curve methods are developed for simultaneously identifying consolidation coefficient, final settlement, and ratio of top and bottom excess pore-water pressures from observed settlements, in the case of linear excess pore-water pressure. Simple equations are also proposed for estimating consolidation coefficient and final settlement. The proposed methods and equations are applicable for any type of linear loading or drainage condition (one-way or two-way drainage). Solutions for pore-water pressure distribution and transient settlement of clay layers under linear loading of pore-water pressure with one-way drainage are also developed, which are used in the development of the methods. The proposed methods do not require full settlement data for the identification of parameters and the parameters can be identified from only initial but adequate settlement data. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2812 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1210–1214
Titre : Consolidation of a double-layered compressible foundation partially penetrated by deep mixed columns Type de document : texte imprimé Auteurs : Linchang Miao, Auteur ; Xinhui Wang, Auteur ; Edward Jr Kavazanjian, Auteur Année de publication : 2008 Article en page(s) : pp. 1210–1214 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Consolidation Foundations Clays Columns Soft soils Résumé : Deep mixed columns often penetrate partially into the soft soil as floating columns due to the depth of the end-bearing layer. Partially penetrated soft soil by columns and the underlying compressible soft soil create a double-layered compressible foundation. So far, no reasonable solution is available to estimate the consolidation of such a double-layered foundation. This paper proposes an analytical solution for consolidation of a double-layered compressible foundation partially penetrated by deep mixed columns considering one-side or two-side vertical drainage The Laplace transform method was used to solve the consolidation equation for the double-layered system while Stehfest’s algorithm was used to solve the inverse Laplace transform for time-dependent loading. A consolidation algorithm was used to calculate the time-settlement relationship of an embankment constructed upon the double-layered foundation partially penetrated by deep mixed columns. The calculated settlements were compared well with field measurements. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2812 [...] [article] Consolidation of a double-layered compressible foundation partially penetrated by deep mixed columns [texte imprimé] / Linchang Miao, Auteur ; Xinhui Wang, Auteur ; Edward Jr Kavazanjian, Auteur . - 2008 . - pp. 1210–1214.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1210–1214
Mots-clés : Consolidation Foundations Clays Columns Soft soils Résumé : Deep mixed columns often penetrate partially into the soft soil as floating columns due to the depth of the end-bearing layer. Partially penetrated soft soil by columns and the underlying compressible soft soil create a double-layered compressible foundation. So far, no reasonable solution is available to estimate the consolidation of such a double-layered foundation. This paper proposes an analytical solution for consolidation of a double-layered compressible foundation partially penetrated by deep mixed columns considering one-side or two-side vertical drainage The Laplace transform method was used to solve the consolidation equation for the double-layered system while Stehfest’s algorithm was used to solve the inverse Laplace transform for time-dependent loading. A consolidation algorithm was used to calculate the time-settlement relationship of an embankment constructed upon the double-layered foundation partially penetrated by deep mixed columns. The calculated settlements were compared well with field measurements. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2812 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1215–1218
Titre : Strength properties of hexametaphosphate treated soils Type de document : texte imprimé Auteurs : Amin Falamaki, Auteur ; Nader Shariatmadari, Auteur ; Ali Noorzad, Auteur Année de publication : 2008 Article en page(s) : pp. 1215–1218 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Soil strength Stabilization Phosphate Dispersion Chemical treatment Grouting Résumé : The present technical note focuses on the potential application of sodium hexametaphosphate (HMP) in geo-environmental engineering. HMP may have many applications in geotechnical and geo-environmental engineering such as: improvement and stabilization of tailing dams, rehabilitation of old landfills, construction of new clay liners, containment and permeable barriers, etc. In this technical note, it is observed that the strength of silty-clayey sand containing a high concentration of metals (like tailings) is increased by mixing of HMP. On the other hand the strength of the kaolinite clay that may be used during the construction of a liner has been reduced by mixing with HMP. In order to study the influence of HMP, soil mixtures with various amount of HMP are prepared to conduct unconfined compression tests. The strength of the HMP-treated kaolinite specimens is always less than the kaolinite specimens for four weeks. HMP has decreased the strength of silty sand during the first days. However, the cations in the soil (specially Ca and Fe) may lead to precipitation and sorption mechanism to govern and, therefore, the strength increases noticeably up to 740%. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2812 [...] [article] Strength properties of hexametaphosphate treated soils [texte imprimé] / Amin Falamaki, Auteur ; Nader Shariatmadari, Auteur ; Ali Noorzad, Auteur . - 2008 . - pp. 1215–1218.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1215–1218
Mots-clés : Soil strength Stabilization Phosphate Dispersion Chemical treatment Grouting Résumé : The present technical note focuses on the potential application of sodium hexametaphosphate (HMP) in geo-environmental engineering. HMP may have many applications in geotechnical and geo-environmental engineering such as: improvement and stabilization of tailing dams, rehabilitation of old landfills, construction of new clay liners, containment and permeable barriers, etc. In this technical note, it is observed that the strength of silty-clayey sand containing a high concentration of metals (like tailings) is increased by mixing of HMP. On the other hand the strength of the kaolinite clay that may be used during the construction of a liner has been reduced by mixing with HMP. In order to study the influence of HMP, soil mixtures with various amount of HMP are prepared to conduct unconfined compression tests. The strength of the HMP-treated kaolinite specimens is always less than the kaolinite specimens for four weeks. HMP has decreased the strength of silty sand during the first days. However, the cations in the soil (specially Ca and Fe) may lead to precipitation and sorption mechanism to govern and, therefore, the strength increases noticeably up to 740%. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2812 [...]
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