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Ajouter le résultat dans votre panierTransient head development due to flood induced seepage under levees / Senda Ozkan in Journal of geotechnical and geoenvironmental engineering, Vol. 134 N° 6 (Juin 2008)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 781–789
Titre : Transient head development due to flood induced seepage under levees Type de document : texte imprimé Auteurs : Senda Ozkan, Auteur ; Donald D. Adrian, Auteur ; George L. Sills, Auteur Année de publication : 2010 Article en page(s) : pp. 781–789 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Floods Seepage Levees Sand Transient flow Water levels Résumé : The purpose of this study was to predict the uplift force during floods on confining layers that overlay extensive horizontal confined aquifers that intersect a large river in response to the water level changes that occur with time in a flooding river. Transient flow of water through the confined aquifer was described by a diffusion type of equation with a boundary condition at the river in which the river head varied with time. The transient head distribution developed from the unsteady flow model applied to the aquifer was compared with the hydraulic head distributions obtained from U.S. Army Corps of Engineers steady-state flow model and a finite-element seepage model. This study concluded that the transient flow model has the potential to analyze time lag in head development, and to predict the seepage condition and heaving potential at various times and distances landside of a levee during a flood cycle, but additional case histories are needed to justify widespread use of the model. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2878 [...] [article] Transient head development due to flood induced seepage under levees [texte imprimé] / Senda Ozkan, Auteur ; Donald D. Adrian, Auteur ; George L. Sills, Auteur . - 2010 . - pp. 781–789.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 781–789
Mots-clés : Floods Seepage Levees Sand Transient flow Water levels Résumé : The purpose of this study was to predict the uplift force during floods on confining layers that overlay extensive horizontal confined aquifers that intersect a large river in response to the water level changes that occur with time in a flooding river. Transient flow of water through the confined aquifer was described by a diffusion type of equation with a boundary condition at the river in which the river head varied with time. The transient head distribution developed from the unsteady flow model applied to the aquifer was compared with the hydraulic head distributions obtained from U.S. Army Corps of Engineers steady-state flow model and a finite-element seepage model. This study concluded that the transient flow model has the potential to analyze time lag in head development, and to predict the seepage condition and heaving potential at various times and distances landside of a levee during a flood cycle, but additional case histories are needed to justify widespread use of the model. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2878 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 790–803
Titre : Empirical predictive models for earthquake-induced sliding displacements of slopes Type de document : texte imprimé Auteurs : Gokhan Saygili, Auteur ; Ellen M. Rathje, Auteur Année de publication : 2010 Article en page(s) : pp. 790–803 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Earthquakes Landslides Slope stability Probability Seismic effects Résumé : Earthquake-induced sliding displacement is the parameter most often used to assess the seismic stability of slopes. The expected displacement can be predicted as a function of the characteristics of the slope (yield acceleration) and the ground motion (e.g., peak ground acceleration), yet there is significant aleatory variability associated with the displacement prediction. Using multiple ground motion parameters to characterize the earthquake shaking can significantly reduce the variability in the prediction. Empirical predictive models for rigid block sliding displacements are developed using displacements calculated from over 2,000 acceleration–time histories and four values of yield acceleration. These empirical models consider various single ground motion parameters and vectors of ground motion parameters to predict the sliding displacement, with the goal of minimizing the standard deviation of the displacement prediction. The combination of peak ground acceleration and peak ground velocity is the two parameter vector that results in the smallest standard deviation in the displacement prediction, whereas the three parameter combination of peak ground acceleration, peak ground velocity, and Arias intensity further reduces the standard deviation. The developed displacement predictive models can be used in probabilistic seismic hazard analysis for sliding displacement or used as predictive tools for deterministic earthquake scenarios. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2879 [...] [article] Empirical predictive models for earthquake-induced sliding displacements of slopes [texte imprimé] / Gokhan Saygili, Auteur ; Ellen M. Rathje, Auteur . - 2010 . - pp. 790–803.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 790–803
Mots-clés : Earthquakes Landslides Slope stability Probability Seismic effects Résumé : Earthquake-induced sliding displacement is the parameter most often used to assess the seismic stability of slopes. The expected displacement can be predicted as a function of the characteristics of the slope (yield acceleration) and the ground motion (e.g., peak ground acceleration), yet there is significant aleatory variability associated with the displacement prediction. Using multiple ground motion parameters to characterize the earthquake shaking can significantly reduce the variability in the prediction. Empirical predictive models for rigid block sliding displacements are developed using displacements calculated from over 2,000 acceleration–time histories and four values of yield acceleration. These empirical models consider various single ground motion parameters and vectors of ground motion parameters to predict the sliding displacement, with the goal of minimizing the standard deviation of the displacement prediction. The combination of peak ground acceleration and peak ground velocity is the two parameter vector that results in the smallest standard deviation in the displacement prediction, whereas the three parameter combination of peak ground acceleration, peak ground velocity, and Arias intensity further reduces the standard deviation. The developed displacement predictive models can be used in probabilistic seismic hazard analysis for sliding displacement or used as predictive tools for deterministic earthquake scenarios. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2879 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 804–814
Titre : Probabilistic seismic hazard analysis for the sliding displacement of slopes : scalar and vector approaches Type de document : texte imprimé Auteurs : Ellen M. Rathje, Auteur ; Gokhan Saygili, Auteur Année de publication : 2010 Article en page(s) : pp. 804–814 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Earthquakes Landslides Slope stability Probability Seismic effects Displacement Résumé : Sliding block displacements often are used to evaluate the potential for ground failure due to slope instability. The procedures used to assess sliding block displacement typically use deterministic or pseudoprobabilistic approaches, in which the uncertainties in the expected ground motion and resulting displacement are either ignored or not treated in a rigorous manner. Thus, there is no concept of the actual hazard associated with the computed displacement. This paper presents a fully probabilistic framework for assessing sliding block displacements. The product of this analysis is a displacement hazard curve, which provides the annual rate of exceedance, λ , for a range of displacement levels. The framework considers two procedures that will yield a displacement hazard curve: (1) a scalar hazard approach that utilizes a single ground motion parameter and its associated hazard curve to compute permanent displacements; and (2) a vector hazard approach that predicts displacements based on two (or more) ground motion parameters and the correlation between these parameters. The vector approach reduces the displacement hazard significantly, as compared with the scalar approach, because of the reduction in the variability in the displacement prediction. Comparison of the fully probabilistic approach with an approach using probabilistically derived ground motions reveals that using a ground motion for a given hazard level does not produce a displacement level with the same hazard. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2880 [...] [article] Probabilistic seismic hazard analysis for the sliding displacement of slopes : scalar and vector approaches [texte imprimé] / Ellen M. Rathje, Auteur ; Gokhan Saygili, Auteur . - 2010 . - pp. 804–814.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 804–814
Mots-clés : Earthquakes Landslides Slope stability Probability Seismic effects Displacement Résumé : Sliding block displacements often are used to evaluate the potential for ground failure due to slope instability. The procedures used to assess sliding block displacement typically use deterministic or pseudoprobabilistic approaches, in which the uncertainties in the expected ground motion and resulting displacement are either ignored or not treated in a rigorous manner. Thus, there is no concept of the actual hazard associated with the computed displacement. This paper presents a fully probabilistic framework for assessing sliding block displacements. The product of this analysis is a displacement hazard curve, which provides the annual rate of exceedance, λ , for a range of displacement levels. The framework considers two procedures that will yield a displacement hazard curve: (1) a scalar hazard approach that utilizes a single ground motion parameter and its associated hazard curve to compute permanent displacements; and (2) a vector hazard approach that predicts displacements based on two (or more) ground motion parameters and the correlation between these parameters. The vector approach reduces the displacement hazard significantly, as compared with the scalar approach, because of the reduction in the variability in the displacement prediction. Comparison of the fully probabilistic approach with an approach using probabilistically derived ground motions reveals that using a ground motion for a given hazard level does not produce a displacement level with the same hazard. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2880 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 815–828
Titre : Liquefaction potential map of Charleston, South Carolina based on the 1886 earthquake Type de document : texte imprimé Auteurs : Hossein Hayati, Auteur ; Ronald D. Andrus, Auteur Année de publication : 2010 Article en page(s) : pp. 815–828 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Cone penetration tests Earthquakes Liquefaction Mapping Shear waves Velocity South Carolina Résumé : A liquefaction potential map of the peninsula of Charleston, S.C., is presented in this paper. Liquefaction potential is expressed in terms of the liquefaction potential index developed by Iwasaki et al. and calculated using 44 cone penetration test profiles. The cone profiles are supplemented with information from the 1:24,000 scale geologic map by Weems and Lemon, several first-hand accounts of liquefaction and ground deformation that occurred during the 1886 Charleston earthquake, and liquefaction probabilities determined by Elton and Hadj-Hamou based on standard penetration tests. Nearly all of the cases of liquefaction and ground deformation occurred in the Holocene to late Pleistocene beach deposits that flank the higher-ground sediments of the Wando Formation. To match the observed field behavior, a deposit resistance correction factor of 1.8 is applied to cyclic resistance ratios calculated for the 100,000-year -old Wando Formation. No corrections are needed for the younger deposits. In additional to 1886 field behavior, the deposit resistance corrections are supported by ratios of measured to predicted shear-wave velocity. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2881 [...] [article] Liquefaction potential map of Charleston, South Carolina based on the 1886 earthquake [texte imprimé] / Hossein Hayati, Auteur ; Ronald D. Andrus, Auteur . - 2010 . - pp. 815–828.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 815–828
Mots-clés : Cone penetration tests Earthquakes Liquefaction Mapping Shear waves Velocity South Carolina Résumé : A liquefaction potential map of the peninsula of Charleston, S.C., is presented in this paper. Liquefaction potential is expressed in terms of the liquefaction potential index developed by Iwasaki et al. and calculated using 44 cone penetration test profiles. The cone profiles are supplemented with information from the 1:24,000 scale geologic map by Weems and Lemon, several first-hand accounts of liquefaction and ground deformation that occurred during the 1886 Charleston earthquake, and liquefaction probabilities determined by Elton and Hadj-Hamou based on standard penetration tests. Nearly all of the cases of liquefaction and ground deformation occurred in the Holocene to late Pleistocene beach deposits that flank the higher-ground sediments of the Wando Formation. To match the observed field behavior, a deposit resistance correction factor of 1.8 is applied to cyclic resistance ratios calculated for the 100,000-year -old Wando Formation. No corrections are needed for the younger deposits. In additional to 1886 field behavior, the deposit resistance corrections are supported by ratios of measured to predicted shear-wave velocity. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2881 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 829–836
Titre : Effects of adsorbed water layer in predicting saturated hydraulic conductivity for clays with Kozeny–Carman equation Type de document : texte imprimé Auteurs : Purnendu N. Singh, Auteur ; Wesley W. Wallender, Auteur Année de publication : 2010 Article en page(s) : pp. 829–836 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Hydraulic conductivity Porous media Clays Predictions Résumé : Saturated hydraulic conductivity for clays predicted using the conventional Kozeny–Carman equation is scalar and found to diverge significantly from measured values. The divergence is consistent and systematic requiring a mathematical derivation of the formula using first principles. The incorporation of the physical characteristics of the adsorbed water layer surrounding a clay particle results in a generalized Kozeny–Carman equation with two new parameters. The porosity correction factor gives the effective porosity taking into account the thickness of the adsorbed water layer and the mass specific surface area of the clay. The second parameter is shown to depend on the interparticle contact area and the interparticle contact stress. The ability of the proposed physically based generalized Kozeny–Carman equation to explain the results from some of the published laboratory permeability tests is tested. The paper results in a new theoretical framework to model changes in saturated hydraulic conductivity in clays where the soil profile is compacting as a result of changes in pore-water pressure and or externally applied loads. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2882 [...] [article] Effects of adsorbed water layer in predicting saturated hydraulic conductivity for clays with Kozeny–Carman equation [texte imprimé] / Purnendu N. Singh, Auteur ; Wesley W. Wallender, Auteur . - 2010 . - pp. 829–836.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 829–836
Mots-clés : Hydraulic conductivity Porous media Clays Predictions Résumé : Saturated hydraulic conductivity for clays predicted using the conventional Kozeny–Carman equation is scalar and found to diverge significantly from measured values. The divergence is consistent and systematic requiring a mathematical derivation of the formula using first principles. The incorporation of the physical characteristics of the adsorbed water layer surrounding a clay particle results in a generalized Kozeny–Carman equation with two new parameters. The porosity correction factor gives the effective porosity taking into account the thickness of the adsorbed water layer and the mass specific surface area of the clay. The second parameter is shown to depend on the interparticle contact area and the interparticle contact stress. The ability of the proposed physically based generalized Kozeny–Carman equation to explain the results from some of the published laboratory permeability tests is tested. The paper results in a new theoretical framework to model changes in saturated hydraulic conductivity in clays where the soil profile is compacting as a result of changes in pore-water pressure and or externally applied loads. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2882 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 837–844
Titre : Predicting the erosion rate of chemically treated soil using a process simulation apparatus for internal crack erosion Type de document : texte imprimé Auteurs : Buddhima Indraratna, Auteur ; Thevaragavan Muttuvel, Auteur ; Hadi Khabbaz, Auteur Année de publication : 2010 Article en page(s) : pp. 837–844 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Soil stabilization Cements Shear stress Soil erosion Soil compaction Predictions Chemicals Cracking Résumé : Chemical stabilization is an effective ground improvement technique for controlling erosion. Two stabilizers, lignosulfonate and cement, were used to study how effectively they could stabilize erodible silty sand collected from Wombeyan Caves, NSW, Australia. To conduct this research, four dosages of cement (0.5, 1, 1.5, and 2%) and four dosages of lignosulfonate (0.1, 0.2, 0.4, and 0.6%) by dry weight of soil were selected. All treated and untreated soil specimens were compacted to 90 and 95% of their maximum dry density to study the effect of compaction level on erodibility. The erosion characteristics of treated and untreated soil samples were investigated using a process simulation apparatus for internal crack erosion designed and built at the University of Wollongong. The findings of this study indicated that both chemical stabilizers increased the resistance to erosion because of their cementing properties. It was also found that the critical shear stress increased linearly with the amount of stabilizer, and the coefficient of soil erosion decreased as a power function of the critical shear stress. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2883 [...] [article] Predicting the erosion rate of chemically treated soil using a process simulation apparatus for internal crack erosion [texte imprimé] / Buddhima Indraratna, Auteur ; Thevaragavan Muttuvel, Auteur ; Hadi Khabbaz, Auteur . - 2010 . - pp. 837–844.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 837–844
Mots-clés : Soil stabilization Cements Shear stress Soil erosion Soil compaction Predictions Chemicals Cracking Résumé : Chemical stabilization is an effective ground improvement technique for controlling erosion. Two stabilizers, lignosulfonate and cement, were used to study how effectively they could stabilize erodible silty sand collected from Wombeyan Caves, NSW, Australia. To conduct this research, four dosages of cement (0.5, 1, 1.5, and 2%) and four dosages of lignosulfonate (0.1, 0.2, 0.4, and 0.6%) by dry weight of soil were selected. All treated and untreated soil specimens were compacted to 90 and 95% of their maximum dry density to study the effect of compaction level on erodibility. The erosion characteristics of treated and untreated soil samples were investigated using a process simulation apparatus for internal crack erosion designed and built at the University of Wollongong. The findings of this study indicated that both chemical stabilizers increased the resistance to erosion because of their cementing properties. It was also found that the critical shear stress increased linearly with the amount of stabilizer, and the coefficient of soil erosion decreased as a power function of the critical shear stress. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2883 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 845–854
Titre : Deep mixing induced property changes in surrounding sensitive marine clays Type de document : texte imprimé Auteurs : Shui-Long Shen, Auteur ; Jie Han, Auteur ; Yan-Jun Du, Auteur Année de publication : 2010 Article en page(s) : pp. 845–854 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Soil mixing Clays Field tests Soil properties Cracking Shear strength Diffusion Résumé : This paper presents a field study of installation effects of deep mixed columns on properties of the sensitive Ariake marine clay. Cone penetration tests were performed in the field to evaluate the change in the strength of the surrounding clay with time. Soil samples were taken before and after column installation to evaluate variations of physical, mechanical, and chemical properties of the surrounding clay. Test results indicated that the water content of the surrounding clay decreased while the concentration of cations increased as sampling locations approached the columns. Shear strength of the surrounding clay decreased during the installation but recovered after a short period of curing. Shear strength continued to increase with time over a period of 70days . Based on the regression results, the surrounding soil after the installation of the columns took approximately 10days to recover to the strength value before installation. On average, the shear strength of the surrounding clay increased over the original strength by approximately 23% after 40days and 50% after 70days , respectively. Discussion is presented on strength changes and key influence factors including soil disturbance and fracturing, thixotropy, consolidation, and diffusion of cations from deep mixed columns to the surrounding clay. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2884 [...] [article] Deep mixing induced property changes in surrounding sensitive marine clays [texte imprimé] / Shui-Long Shen, Auteur ; Jie Han, Auteur ; Yan-Jun Du, Auteur . - 2010 . - pp. 845–854.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 845–854
Mots-clés : Soil mixing Clays Field tests Soil properties Cracking Shear strength Diffusion Résumé : This paper presents a field study of installation effects of deep mixed columns on properties of the sensitive Ariake marine clay. Cone penetration tests were performed in the field to evaluate the change in the strength of the surrounding clay with time. Soil samples were taken before and after column installation to evaluate variations of physical, mechanical, and chemical properties of the surrounding clay. Test results indicated that the water content of the surrounding clay decreased while the concentration of cations increased as sampling locations approached the columns. Shear strength of the surrounding clay decreased during the installation but recovered after a short period of curing. Shear strength continued to increase with time over a period of 70days . Based on the regression results, the surrounding soil after the installation of the columns took approximately 10days to recover to the strength value before installation. On average, the shear strength of the surrounding clay increased over the original strength by approximately 23% after 40days and 50% after 70days , respectively. Discussion is presented on strength changes and key influence factors including soil disturbance and fracturing, thixotropy, consolidation, and diffusion of cations from deep mixed columns to the surrounding clay. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2884 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 855–865
Titre : Measuring soil pressure on a buried model structure for the validation of quantitative frameworks Type de document : texte imprimé Auteurs : Mark Talesnick, Auteur ; Hanna Horany, Auteur ; Avraham N. Dancygier, Auteur Année de publication : 2010 Article en page(s) : pp. 855–865 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Soil pressure Measurement Underground structures Validation Résumé : The paper presents the methodologies and results of an experimental study aimed at measuring the soil contact pressures which develop on a buried structure as it interacts with the surrounding soil under load. The study has been based on measurements made on model structures tested in a pressure chamber filled with a fine uniform sand. The buried model structure was a very rigid right cylinder designed such that it could be fitted with roofs of different thicknesses. The structure bottom and roof were instrumented with newly designed and constructed soil pressure cells based on the null response concept. The device is unaffected by the issues that affect the use of traditional soil pressure cells. The development of pressure on the structure was measured as uniform pressure was applied to the soil surface. The results illustrate the effect of roof stiffness on the development of pressure at the roof center. The midroof pressure was seen to increase with roof stiffness, however the development of pressure was also seen to be dependent upon the actual deflection. In the case of a flexible roof it was seen that the development of contact pressure is a nonlinear function of the pressure applied at the soil surface and is highly dependent upon stress history. In contrast, it was seen that pressure on a stiff roof develops as a linear function of pressure applied at the soil surface and is less dependent of stress history. The results of the model tests together with soil stiffness data supplied in the paper will be useful in the calibration and validation of numerical and analytical frameworks. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2885 [...] [article] Measuring soil pressure on a buried model structure for the validation of quantitative frameworks [texte imprimé] / Mark Talesnick, Auteur ; Hanna Horany, Auteur ; Avraham N. Dancygier, Auteur . - 2010 . - pp. 855–865.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 855–865
Mots-clés : Soil pressure Measurement Underground structures Validation Résumé : The paper presents the methodologies and results of an experimental study aimed at measuring the soil contact pressures which develop on a buried structure as it interacts with the surrounding soil under load. The study has been based on measurements made on model structures tested in a pressure chamber filled with a fine uniform sand. The buried model structure was a very rigid right cylinder designed such that it could be fitted with roofs of different thicknesses. The structure bottom and roof were instrumented with newly designed and constructed soil pressure cells based on the null response concept. The device is unaffected by the issues that affect the use of traditional soil pressure cells. The development of pressure on the structure was measured as uniform pressure was applied to the soil surface. The results illustrate the effect of roof stiffness on the development of pressure at the roof center. The midroof pressure was seen to increase with roof stiffness, however the development of pressure was also seen to be dependent upon the actual deflection. In the case of a flexible roof it was seen that the development of contact pressure is a nonlinear function of the pressure applied at the soil surface and is highly dependent upon stress history. In contrast, it was seen that pressure on a stiff roof develops as a linear function of pressure applied at the soil surface and is less dependent of stress history. The results of the model tests together with soil stiffness data supplied in the paper will be useful in the calibration and validation of numerical and analytical frameworks. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2885 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 866-875
Titre : Numerical simulation of vertical pullout of plate anchors in clay Type de document : texte imprimé Auteurs : Zhenhe Song, Auteur ; Yuxia Hu, Auteur ; Mark F. Randolph, Auteur Année de publication : 2010 Article en page(s) : pp. 866-875 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Anchors Pull out resistance Soil strength Deep water Finite element method Deformation Résumé : The behavior of strip and circular plate anchors during vertical pullout in uniform and normally consolidated clays was studied in this paper by means of small strain and large deformation finite-element analyses. Both fully bonded (attached), and “vented” (no suction on rear face), anchors were considered. The current numerical results were compared with existing laboratory test data, finite-element results, and analytical solutions. This study showed that, in small strain analysis, the scatter of existing data was mainly due to the effect of soil stiffness. In large deformation analysis, when soil and anchor base were attached with suction, the pullout capacity factor formed a unique curve independent of the soil strength (su) , soil effective unit weight (γ′) and anchor size ( B =width of strip anchor and D =diameter of circular anchor). The transitional embedment depth ratio, HSD∕B or HSD∕D , (where HSD =transition depth between shallow and deep embedment) was 1.4 for a strip anchor and 0.75 for a circular anchor. The ultimate pullout capacity factors (Nc) for deep embedment were 11.6 and 11.7 for smooth and rough strip anchors and 13.1 and 13.7 for smooth and rough circular anchors, respectively. However, when the anchor base was vented, the soil stayed attached to the anchor base for deep embedment, and the pullout capacity was therefore the same as for the attached anchor. The separation depth ratio, Hs∕B or Hs∕D , (where Hs =embedment depth at which the soil and anchor base separated) was found to increase linearly with the normalized strength ratio, su/γ′B or su / γ′D . En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2886 [...] [article] Numerical simulation of vertical pullout of plate anchors in clay [texte imprimé] / Zhenhe Song, Auteur ; Yuxia Hu, Auteur ; Mark F. Randolph, Auteur . - 2010 . - pp. 866-875.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 866-875
Mots-clés : Anchors Pull out resistance Soil strength Deep water Finite element method Deformation Résumé : The behavior of strip and circular plate anchors during vertical pullout in uniform and normally consolidated clays was studied in this paper by means of small strain and large deformation finite-element analyses. Both fully bonded (attached), and “vented” (no suction on rear face), anchors were considered. The current numerical results were compared with existing laboratory test data, finite-element results, and analytical solutions. This study showed that, in small strain analysis, the scatter of existing data was mainly due to the effect of soil stiffness. In large deformation analysis, when soil and anchor base were attached with suction, the pullout capacity factor formed a unique curve independent of the soil strength (su) , soil effective unit weight (γ′) and anchor size ( B =width of strip anchor and D =diameter of circular anchor). The transitional embedment depth ratio, HSD∕B or HSD∕D , (where HSD =transition depth between shallow and deep embedment) was 1.4 for a strip anchor and 0.75 for a circular anchor. The ultimate pullout capacity factors (Nc) for deep embedment were 11.6 and 11.7 for smooth and rough strip anchors and 13.1 and 13.7 for smooth and rough circular anchors, respectively. However, when the anchor base was vented, the soil stayed attached to the anchor base for deep embedment, and the pullout capacity was therefore the same as for the attached anchor. The separation depth ratio, Hs∕B or Hs∕D , (where Hs =embedment depth at which the soil and anchor base separated) was found to increase linearly with the normalized strength ratio, su/γ′B or su / γ′D . En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2886 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 876–882
Titre : Improved approach to construct constitutive surfaces for stable-structured soils covering both saturated and unsaturated conditions Type de document : texte imprimé Auteurs : Xiong Zhang, Auteur ; Jean-Louis Briaud, Auteur Année de publication : 2010 Article en page(s) : pp. 876–882 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Void ratio Saturated soils Unsaturated soils Laboratory tests Surface properties Résumé : Constitutive surfaces are indispensable for investigation of the behavior of soils. Saturated and unsaturated soils coexist in most engineering problems and it is meaningful to develop constitutive surfaces covering both saturated and unsaturated conditions which help to investigate the behavior for both saturated and unsaturated soils in a unified way. At present, the methodologies used for saturated and unsaturated soils are different and few researchers consider the constitutive surfaces for saturated soils. For unsaturated soils, the suction-controlled triaxial tests are usually laborious, time consuming, costly, and may not justify routine engineering projects. This paper discusses the role of constitutive surfaces in soil mechanics and presents an improved approach over existing interpolation methods to construct the constitutive surfaces for saturated and unsaturated conditions for a stable-structured soil using simple laboratory tests. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2887 [...] [article] Improved approach to construct constitutive surfaces for stable-structured soils covering both saturated and unsaturated conditions [texte imprimé] / Xiong Zhang, Auteur ; Jean-Louis Briaud, Auteur . - 2010 . - pp. 876–882.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 876–882
Mots-clés : Void ratio Saturated soils Unsaturated soils Laboratory tests Surface properties Résumé : Constitutive surfaces are indispensable for investigation of the behavior of soils. Saturated and unsaturated soils coexist in most engineering problems and it is meaningful to develop constitutive surfaces covering both saturated and unsaturated conditions which help to investigate the behavior for both saturated and unsaturated soils in a unified way. At present, the methodologies used for saturated and unsaturated soils are different and few researchers consider the constitutive surfaces for saturated soils. For unsaturated soils, the suction-controlled triaxial tests are usually laborious, time consuming, costly, and may not justify routine engineering projects. This paper discusses the role of constitutive surfaces in soil mechanics and presents an improved approach over existing interpolation methods to construct the constitutive surfaces for saturated and unsaturated conditions for a stable-structured soil using simple laboratory tests. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2887 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 883–887
Titre : Further advancement in filtration criteria through constriction-based techniques Type de document : texte imprimé Auteurs : Ashok K. Raut, Auteur ; Buddhima Indraratna, Auteur Année de publication : 2010 Article en page(s) : pp. 883–887 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Filtration Particle size Dams Embankment Cohesionless soils Résumé : In this technical note, the concept of constriction size in design is highlighted while elucidating some of the limitations of current professional guidelines that are only based on particle size ratios. The implications of the controlling constriction size, Dc35 , and the self-filtering constriction size, Dc95 , are elaborated on; Dc35 =constriction size whereby 35% of the filter constrictions are finer than this, and Dc95 =constriction size whereby 95% of the filter constrictions are finer than this. Combining the salient findings of two recent papers by Indraratna et al. in 2007 and Indraratna and Raut in 2006, a further refinement for filter design, i.e., Dc35/d∗85⩽1 , is introduced here based on the self-filtering base fraction and controlling constriction size of the filter, where the specific parameter d∗85 =value of d85 of the base soil grading curve modified by the self-filtering constriction size, Dc95 . The proposed criterion is verified using several large-scale tests carried out at the University of Wollongong and numerous test data available in the literature. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2888 [...] [article] Further advancement in filtration criteria through constriction-based techniques [texte imprimé] / Ashok K. Raut, Auteur ; Buddhima Indraratna, Auteur . - 2010 . - pp. 883–887.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 883–887
Mots-clés : Filtration Particle size Dams Embankment Cohesionless soils Résumé : In this technical note, the concept of constriction size in design is highlighted while elucidating some of the limitations of current professional guidelines that are only based on particle size ratios. The implications of the controlling constriction size, Dc35 , and the self-filtering constriction size, Dc95 , are elaborated on; Dc35 =constriction size whereby 35% of the filter constrictions are finer than this, and Dc95 =constriction size whereby 95% of the filter constrictions are finer than this. Combining the salient findings of two recent papers by Indraratna et al. in 2007 and Indraratna and Raut in 2006, a further refinement for filter design, i.e., Dc35/d∗85⩽1 , is introduced here based on the self-filtering base fraction and controlling constriction size of the filter, where the specific parameter d∗85 =value of d85 of the base soil grading curve modified by the self-filtering constriction size, Dc95 . The proposed criterion is verified using several large-scale tests carried out at the University of Wollongong and numerous test data available in the literature. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2888 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 888–893
Titre : Analytical construction of transient flow nets in homogeneous and isotropic flow medium Type de document : texte imprimé Auteurs : Senda Ozkan, Auteur ; Donald D. Adrian, Auteur Année de publication : 2010 Article en page(s) : pp. 888–893 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Water flow Transient flow Seepage Time dependence Hydraulic structures Résumé : The purpose of this study is to construct time-dependent flow nets, also called transient flow nets in homogenous and isotropic flow medium. Transient flow nets under hydraulic structures are developed in response to reservoir head fluctuations. An analytical solution for a transient flow net has not been reported in the literature. Time-dependent flow net equations are limited in engineering applications to simple boundary conditions. The geometry of transient flow nets does not change with time, as only the numerical values assigned to equipotential lines and flow lines change with time. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2888 [...] [article] Analytical construction of transient flow nets in homogeneous and isotropic flow medium [texte imprimé] / Senda Ozkan, Auteur ; Donald D. Adrian, Auteur . - 2010 . - pp. 888–893.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 888–893
Mots-clés : Water flow Transient flow Seepage Time dependence Hydraulic structures Résumé : The purpose of this study is to construct time-dependent flow nets, also called transient flow nets in homogenous and isotropic flow medium. Transient flow nets under hydraulic structures are developed in response to reservoir head fluctuations. An analytical solution for a transient flow net has not been reported in the literature. Time-dependent flow net equations are limited in engineering applications to simple boundary conditions. The geometry of transient flow nets does not change with time, as only the numerical values assigned to equipotential lines and flow lines change with time. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2888 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 894–898
Titre : OCR prediction using support vector machine based on piezocone data Type de document : texte imprimé Auteurs : Pijush Samui, Auteur ; T. G. Sitharam, Auteur ; Pradeep U. Kurup, Auteur Année de publication : 2010 Article en page(s) : pp. 894–898 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Predictions Vector analysis Data analysis Résumé : The determination of the overconsolidation ratio (OCR) of clay deposits is an important task in geotechnical engineering practice. This paper examines the potential of a support vector machine (SVM) for predicting the OCR of clays from piezocone penetration test data. SVM is a statistical learning theory based on a structural risk minimization principle that minimizes both error and weight terms. The five input variables used for the SVM model for prediction of OCR are the corrected cone resistance (qt) , vertical total stress (σv) , hydrostatic pore pressure (u0) , pore pressure at the cone tip (u1) , and the pore pressure just above the cone base (u2) . Sensitivity analysis has been performed to investigate the relative importance of each of the input parameters. From the sensitivity analysis, it is clear that qt =primary in situ data influenced by OCR followed by σv , u0 , u2 , and u1 . Comparison between SVM and some of the traditional interpretation methods is also presented. The results of this study have shown that the SVM approach has the potential to be a practical tool for determination of OCR. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2889 [...] [article] OCR prediction using support vector machine based on piezocone data [texte imprimé] / Pijush Samui, Auteur ; T. G. Sitharam, Auteur ; Pradeep U. Kurup, Auteur . - 2010 . - pp. 894–898.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 894–898
Mots-clés : Predictions Vector analysis Data analysis Résumé : The determination of the overconsolidation ratio (OCR) of clay deposits is an important task in geotechnical engineering practice. This paper examines the potential of a support vector machine (SVM) for predicting the OCR of clays from piezocone penetration test data. SVM is a statistical learning theory based on a structural risk minimization principle that minimizes both error and weight terms. The five input variables used for the SVM model for prediction of OCR are the corrected cone resistance (qt) , vertical total stress (σv) , hydrostatic pore pressure (u0) , pore pressure at the cone tip (u1) , and the pore pressure just above the cone base (u2) . Sensitivity analysis has been performed to investigate the relative importance of each of the input parameters. From the sensitivity analysis, it is clear that qt =primary in situ data influenced by OCR followed by σv , u0 , u2 , and u1 . Comparison between SVM and some of the traditional interpretation methods is also presented. The results of this study have shown that the SVM approach has the potential to be a practical tool for determination of OCR. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2889 [...]
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 894–898
Titre : OCR prediction using support vector machine based on piezocone data Type de document : texte imprimé Auteurs : Pijush Samui, Auteur ; T. G. Sitharam, Auteur ; Pradeep U. Kurup, Auteur Année de publication : 2010 Article en page(s) : pp. 894–898 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Predictions Vector analysis Data analysis Résumé : The determination of the overconsolidation ratio (OCR) of clay deposits is an important task in geotechnical engineering practice. This paper examines the potential of a support vector machine (SVM) for predicting the OCR of clays from piezocone penetration test data. SVM is a statistical learning theory based on a structural risk minimization principle that minimizes both error and weight terms. The five input variables used for the SVM model for prediction of OCR are the corrected cone resistance (qt) , vertical total stress (σv) , hydrostatic pore pressure (u0) , pore pressure at the cone tip (u1) , and the pore pressure just above the cone base (u2) . Sensitivity analysis has been performed to investigate the relative importance of each of the input parameters. From the sensitivity analysis, it is clear that qt =primary in situ data influenced by OCR followed by σv , u0 , u2 , and u1 . Comparison between SVM and some of the traditional interpretation methods is also presented. The results of this study have shown that the SVM approach has the potential to be a practical tool for determination of OCR. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2889 [...] [article] OCR prediction using support vector machine based on piezocone data [texte imprimé] / Pijush Samui, Auteur ; T. G. Sitharam, Auteur ; Pradeep U. Kurup, Auteur . - 2010 . - pp. 894–898.
Geotechnical and geoenvironmental engineering
Langues : Anglais (eng)
in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 894–898
Mots-clés : Predictions Vector analysis Data analysis Résumé : The determination of the overconsolidation ratio (OCR) of clay deposits is an important task in geotechnical engineering practice. This paper examines the potential of a support vector machine (SVM) for predicting the OCR of clays from piezocone penetration test data. SVM is a statistical learning theory based on a structural risk minimization principle that minimizes both error and weight terms. The five input variables used for the SVM model for prediction of OCR are the corrected cone resistance (qt) , vertical total stress (σv) , hydrostatic pore pressure (u0) , pore pressure at the cone tip (u1) , and the pore pressure just above the cone base (u2) . Sensitivity analysis has been performed to investigate the relative importance of each of the input parameters. From the sensitivity analysis, it is clear that qt =primary in situ data influenced by OCR followed by σv , u0 , u2 , and u1 . Comparison between SVM and some of the traditional interpretation methods is also presented. The results of this study have shown that the SVM approach has the potential to be a practical tool for determination of OCR. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2889 [...]
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