Ahmed Arab - Academia.edu (original) (raw)
Papers by Ahmed Arab
This paper reports the results of a series of drained triaxial tests on the Chlef soil reinforced... more This paper reports the results of a series of drained triaxial tests on the Chlef soil reinforced with geotextile. The tests were carried out on samples reconstituted with an initial density index ID =10% and subjected to initial confining pressure of 50, 100 and 200 kPa. The test results indicated that the presence of geotextile layers affects significantly the shear strength of the soil. Indeed, the shear strength of the soil increases with the increase of geotextile and confining pressure. The soil contractancy increases with the increase of geotextile and confinement. The mobilized internal friction angle increases significantly with the increase of geotextile and decreases with the increase of the confinement.
Liquefaction of sandy soil deposits during earthquakes has been one of the most important problem... more Liquefaction of sandy soil deposits during earthquakes has been one of the most important problems in the field of geotechnical earthquake engineering. A major challenge is the assessment of the appropriate undrained shear strength of liquefied soils to be used in the study of liquefaction stability of different types of earth structures (embankments, earthdams, etc.). The objective of this laboratory investigation is to study of soil reinforcements Chlef on the behavior of a silty sand with a relative density (Dr = 50%). The Note is composed of three parts. The first presents the soils studied, the second provides an analysis of test results monotonic drained and undrained made and discusses the influence of soil reinforcement by types of geotextiles on the mechanical properties of sand. The tests show that the increased use of geotextile sheets increased the diverter forced soil and reduces the volumetric strain ξv soil. The third part presents the influence of the secant modulus ...
Les resultats des essais ont montre que la presence de nappes de geotextiles influe d’une maniere... more Les resultats des essais ont montre que la presence de nappes de geotextiles influe d’une maniere considerable la resistance au cisaillement, la resistance du sol augmente avec l’augmentation du nombre de geotextiles et avec l’augmentation de la contrainte confinement. La contractance du sol augmente avec l’augmentation du nombre de geotextiles et a vec l’augmentation du confinement. L’angle de frottement interne mobilise augmente d’une maniere significative avec l’augmentation du nombre de geotextiles et diminue avec l’augmentation du confinement.
Resume : Une etude experimentale, realisee en laboratoire a l’appareil triaxial, se propose d’eva... more Resume : Une etude experimentale, realisee en laboratoire a l’appareil triaxial, se propose d’evaluer l'influence de la methode de preparation des echantillons sur le comportement non draine du sable de Chlef. Les essais ont ete effectues sur des echantillons de densite relative initiale de 29 et 50%, a des pressions de confinement initiales de 50, 100 et 200 kPa selon deux methodes de reconstitution : la pluviation a sec et le placement humide. Tous les echantillons ont ete soumis a un chargement monotone apres consolidation. Les resultats experimentaux montrent que la pression de confinement et la densite relative affectent d’une maniere tres significative la resistance a la liquefaction du sol. En effet cette derniere augmente avec la pression de confinement et la densite. Les resultats montrent aussi que les echantillons prepares avec la methode de pluviation a sec presentent une resistance a la liquefaction plus elevee que ceux prepares avec la methode du placement humide.
The effects of confining pressure, relative density and sample preparation methods on the shearin... more The effects of confining pressure, relative density and sample preparation methods on the shearing strength of Chlef sand were studied in this article. For this purpose, the results of drained and undrained monotonic triaxial compression tests performed on samples with initial density of 0.29 and 0.80 under initial confining pressures ranged from 50 to 200 kPa are presented. The specimens were prepared by two depositional methods namely dry funnel pluviation and wet deposition. It was found that there was a marked difference in the undrained behavior even though the density and stress conditions were identical. The conclusion was that the soil fabric was responsible for this result. The results indicated also that at low confining pressures, the specimens reconstituted by the wet deposition method exhibited complete static liquefaction (zero effective confining pressure and zero stress difference). As confining pressures and densities were increased, the effective stress paths indic...
International Journal of Geotechnical Engineering, 2016
RESUME : Cet article décrit le phénomène de liquéfaction, le processus et les méthodes d'éval... more RESUME : Cet article décrit le phénomène de liquéfaction, le processus et les méthodes d'évaluation de ce risque. Les techniques utilisés pour l'amélioration de la résistance à la liquéfaction sont comparés, notamment en agissant sur les paramètres indice des vides et drainage. En plus une étude en laboratoire de la micro-zonation de la ville de Chlef comportant des essais en laboratoire sur des chemins drainés et non drainés ont été réalisés à l'appareil triaxial sur le sol de Chlef. Les résultas montrent que la résistance à la liquéfaction est très influencée par la présence des fines, la résistance à la liquéfaction diminue avec l'augmentation de la fraction des fines. L'étude du renforcement du sol de Chlef par augmentation de la densité relative, inclusions de nappes de géotextiles, colonnes ballastés et micro-pieux de sable compacté montre une amélioration et stabilisation très significative de la résistance à la liquéfaction par rapport au sol vierge. MOTS...
This paper presents a laboratory study of the influence of low plastic fines and preloading on th... more This paper presents a laboratory study of the influence of low plastic fines and preloading on the cyclic behaviour of silty sand. The study is based on undrained triaxial cyclic tests which were carried out for fines content ranging from 0 to 40%. The paper is composed of three parts. The first one presents the characteristics of soils used in this study; the second provides an analysis of the effect of low plastic fines on the cyclic behaviour of the sand-silt mixtures. The third part presents the effect of the preloading on the soil liquefaction. The test results indicate that the liquefaction potential of the mixtures decreases with increasing the fines content until Fc=20%, after which the potential of liquefaction increases moderately with the fines content Fc=40%. The over-consolidation and the cyclic drained preloading of low stress amplitude improved the liquefaction resistance of the sand-silt mixtures.
Geotechnical Testing Journal, 2014
Arabian Journal for Science and Engineering, 2014
Special Topics & Reviews in Porous Media - An International Journal, 2012
Environmental Earth Sciences, 2013
Periodica Polytechnica Civil Engineering, 2010
Marine Georesources & Geotechnology, 2014
ABSTRACT The hydraulic conductivity plays a major role on the excess pore pressure generation dur... more ABSTRACT The hydraulic conductivity plays a major role on the excess pore pressure generation during monotonic and cyclic loading of granular soils with fines. This paper aims to determine how much the hydraulic conductivity and pore pressure response of the sand-silt mixtures are affected by the percentage of fines and void ratio of the soil. The results of flexible wall permeameter and undrained monotonic triaxial tests performed on samples reconstituted from Chlef River sand with 0, 10, 20, 30, 40, and 50% nonplastic silt at an effective confining stress of 100 kPa and two relative densities (Dr¼20, and 91%) are presented and discussed. It was found that the pore pressure increases linearly with the increase of the fines content and logarithmically with the increase of the intergranular void ratio. The results obtained from this study reveal that the saturated hydraulic conductivity (k) of the sand mixed with 50% low plastic fines can be, on average, four orders of magnitude smaller than that of the clean sand. The results show also that the hydraulic conductivity decreases hyperbolically with the increase of the fines content and the intergranular void ratio.
Journal of Iberian Geology, 2011
This paper reports the results of a series of drained triaxial tests on the Chlef soil reinforced... more This paper reports the results of a series of drained triaxial tests on the Chlef soil reinforced with geotextile. The tests were carried out on samples reconstituted with an initial density index ID =10% and subjected to initial confining pressure of 50, 100 and 200 kPa. The test results indicated that the presence of geotextile layers affects significantly the shear strength of the soil. Indeed, the shear strength of the soil increases with the increase of geotextile and confining pressure. The soil contractancy increases with the increase of geotextile and confinement. The mobilized internal friction angle increases significantly with the increase of geotextile and decreases with the increase of the confinement.
Liquefaction of sandy soil deposits during earthquakes has been one of the most important problem... more Liquefaction of sandy soil deposits during earthquakes has been one of the most important problems in the field of geotechnical earthquake engineering. A major challenge is the assessment of the appropriate undrained shear strength of liquefied soils to be used in the study of liquefaction stability of different types of earth structures (embankments, earthdams, etc.). The objective of this laboratory investigation is to study of soil reinforcements Chlef on the behavior of a silty sand with a relative density (Dr = 50%). The Note is composed of three parts. The first presents the soils studied, the second provides an analysis of test results monotonic drained and undrained made and discusses the influence of soil reinforcement by types of geotextiles on the mechanical properties of sand. The tests show that the increased use of geotextile sheets increased the diverter forced soil and reduces the volumetric strain ξv soil. The third part presents the influence of the secant modulus ...
Les resultats des essais ont montre que la presence de nappes de geotextiles influe d’une maniere... more Les resultats des essais ont montre que la presence de nappes de geotextiles influe d’une maniere considerable la resistance au cisaillement, la resistance du sol augmente avec l’augmentation du nombre de geotextiles et avec l’augmentation de la contrainte confinement. La contractance du sol augmente avec l’augmentation du nombre de geotextiles et a vec l’augmentation du confinement. L’angle de frottement interne mobilise augmente d’une maniere significative avec l’augmentation du nombre de geotextiles et diminue avec l’augmentation du confinement.
Resume : Une etude experimentale, realisee en laboratoire a l’appareil triaxial, se propose d’eva... more Resume : Une etude experimentale, realisee en laboratoire a l’appareil triaxial, se propose d’evaluer l'influence de la methode de preparation des echantillons sur le comportement non draine du sable de Chlef. Les essais ont ete effectues sur des echantillons de densite relative initiale de 29 et 50%, a des pressions de confinement initiales de 50, 100 et 200 kPa selon deux methodes de reconstitution : la pluviation a sec et le placement humide. Tous les echantillons ont ete soumis a un chargement monotone apres consolidation. Les resultats experimentaux montrent que la pression de confinement et la densite relative affectent d’une maniere tres significative la resistance a la liquefaction du sol. En effet cette derniere augmente avec la pression de confinement et la densite. Les resultats montrent aussi que les echantillons prepares avec la methode de pluviation a sec presentent une resistance a la liquefaction plus elevee que ceux prepares avec la methode du placement humide.
The effects of confining pressure, relative density and sample preparation methods on the shearin... more The effects of confining pressure, relative density and sample preparation methods on the shearing strength of Chlef sand were studied in this article. For this purpose, the results of drained and undrained monotonic triaxial compression tests performed on samples with initial density of 0.29 and 0.80 under initial confining pressures ranged from 50 to 200 kPa are presented. The specimens were prepared by two depositional methods namely dry funnel pluviation and wet deposition. It was found that there was a marked difference in the undrained behavior even though the density and stress conditions were identical. The conclusion was that the soil fabric was responsible for this result. The results indicated also that at low confining pressures, the specimens reconstituted by the wet deposition method exhibited complete static liquefaction (zero effective confining pressure and zero stress difference). As confining pressures and densities were increased, the effective stress paths indic...
International Journal of Geotechnical Engineering, 2016
RESUME : Cet article décrit le phénomène de liquéfaction, le processus et les méthodes d'éval... more RESUME : Cet article décrit le phénomène de liquéfaction, le processus et les méthodes d'évaluation de ce risque. Les techniques utilisés pour l'amélioration de la résistance à la liquéfaction sont comparés, notamment en agissant sur les paramètres indice des vides et drainage. En plus une étude en laboratoire de la micro-zonation de la ville de Chlef comportant des essais en laboratoire sur des chemins drainés et non drainés ont été réalisés à l'appareil triaxial sur le sol de Chlef. Les résultas montrent que la résistance à la liquéfaction est très influencée par la présence des fines, la résistance à la liquéfaction diminue avec l'augmentation de la fraction des fines. L'étude du renforcement du sol de Chlef par augmentation de la densité relative, inclusions de nappes de géotextiles, colonnes ballastés et micro-pieux de sable compacté montre une amélioration et stabilisation très significative de la résistance à la liquéfaction par rapport au sol vierge. MOTS...
This paper presents a laboratory study of the influence of low plastic fines and preloading on th... more This paper presents a laboratory study of the influence of low plastic fines and preloading on the cyclic behaviour of silty sand. The study is based on undrained triaxial cyclic tests which were carried out for fines content ranging from 0 to 40%. The paper is composed of three parts. The first one presents the characteristics of soils used in this study; the second provides an analysis of the effect of low plastic fines on the cyclic behaviour of the sand-silt mixtures. The third part presents the effect of the preloading on the soil liquefaction. The test results indicate that the liquefaction potential of the mixtures decreases with increasing the fines content until Fc=20%, after which the potential of liquefaction increases moderately with the fines content Fc=40%. The over-consolidation and the cyclic drained preloading of low stress amplitude improved the liquefaction resistance of the sand-silt mixtures.
Geotechnical Testing Journal, 2014
Arabian Journal for Science and Engineering, 2014
Special Topics & Reviews in Porous Media - An International Journal, 2012
Environmental Earth Sciences, 2013
Periodica Polytechnica Civil Engineering, 2010
Marine Georesources & Geotechnology, 2014
ABSTRACT The hydraulic conductivity plays a major role on the excess pore pressure generation dur... more ABSTRACT The hydraulic conductivity plays a major role on the excess pore pressure generation during monotonic and cyclic loading of granular soils with fines. This paper aims to determine how much the hydraulic conductivity and pore pressure response of the sand-silt mixtures are affected by the percentage of fines and void ratio of the soil. The results of flexible wall permeameter and undrained monotonic triaxial tests performed on samples reconstituted from Chlef River sand with 0, 10, 20, 30, 40, and 50% nonplastic silt at an effective confining stress of 100 kPa and two relative densities (Dr¼20, and 91%) are presented and discussed. It was found that the pore pressure increases linearly with the increase of the fines content and logarithmically with the increase of the intergranular void ratio. The results obtained from this study reveal that the saturated hydraulic conductivity (k) of the sand mixed with 50% low plastic fines can be, on average, four orders of magnitude smaller than that of the clean sand. The results show also that the hydraulic conductivity decreases hyperbolically with the increase of the fines content and the intergranular void ratio.
Journal of Iberian Geology, 2011