Dépouillements

Study of scale effect in an internal erosion mechanism / Didier Marot in European journal of environmental and civil engineering, Vol. 16 N° 1 (Janvier 2012) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 16 N° 1 (Janvier 2012) . - pp. 1-19 Titre : Study of scale effect in an internal erosion mechanism : Centrifuge model and energy analysis Type de document : texte imprimé Auteurs : Didier Marot, Auteur ; Jacques Garnier, Auteur ; Luc Thorel, Auteur Année de publication : 2012 Article en page(s) : pp. 1-19 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Suffusion  Scale  effect  Centrifuge  bench  Erosion  model  Energy  analysis Résumé : Suffusion is an internal erosion mechanism, which means detachment and transport of fine particles within the soil skeleton due to hydraulic seepage flows. Different researchers have observed that the value of the critical hydraulic gradient required to initiate suffusion decreases with the length of the specimen tested. A specific centrifuge bench was designed to study the suffusion process and to study this scale effect under a controlled effective stress. Clayey sand specimens were subjected to centrifuge acceleration and to a downward flow under a constant hydraulic head. The study underlines the influence of specimen length on critical hydraulic gradient and also on the rate of erosion. A new energy analysis of tests is developed, linking the erosion rate to the power expended by fluid flow, and the eroded clay mass to the energy dissipation. This method permits the effect of specimen length to be avoided. DEWEY : 624 ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/abs/10.1080/19648189.2012.667203 [article] Study of scale effect in an internal erosion mechanism : Centrifuge model and energy analysis [texte imprimé] / Didier Marot, Auteur ; Jacques Garnier, Auteur ; Luc Thorel, Auteur . - 2012 . - pp. 1-19. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 16 N° 1 (Janvier 2012) . - pp. 1-19 Mots-clés : Suffusion  Scale  effect  Centrifuge  bench  Erosion  model  Energy  analysis Résumé : Suffusion is an internal erosion mechanism, which means detachment and transport of fine particles within the soil skeleton due to hydraulic seepage flows. Different researchers have observed that the value of the critical hydraulic gradient required to initiate suffusion decreases with the length of the specimen tested. A specific centrifuge bench was designed to study the suffusion process and to study this scale effect under a controlled effective stress. Clayey sand specimens were subjected to centrifuge acceleration and to a downward flow under a constant hydraulic head. The study underlines the influence of specimen length on critical hydraulic gradient and also on the rate of erosion. A new energy analysis of tests is developed, linking the erosion rate to the power expended by fluid flow, and the eroded clay mass to the energy dissipation. This method permits the effect of specimen length to be avoided. DEWEY : 624 ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/abs/10.1080/19648189.2012.667203

Structural monitoring / Z. Boukria in European journal of environmental and civil engineering, Vol. 16 N° 1 (Janvier 2012) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 16 N° 1 (Janvier 2012) . - pp. 20-42 Titre : Structural monitoring : Identification and location of an impact on a structurally dissipating rock-shed structure using the inverse method Type de document : texte imprimé Auteurs : Z. Boukria, Auteur ; P. Perrotin, Auteur ; A. Bennani, Auteur Année de publication : 2012 Article en page(s) : pp. 20-42 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Inverse  problem  Identification  Location  Transfer  function  Reinforced  concrete  slab  Tikhonov  regularisation  Numerical  model Résumé : In this study we developed an experimental method to identify the impact force on a reinforced concrete slab. A transfer function obtained experimentally between the acceleration response and the force history applied to a point of the structure was used. To regularise the solution obtained with this inverse problem, we used the Tikhonov method. To locate the impact force, we used an experimental method based on the minimisation of an objective function created from the transfer functions between several impact locations, forming a mesh structure, and several measuring points. Characterising the impact means locating the impactor and identifying the load. Meanwhile, a numerical model is developed using Abaqus to characterise impact force, and allow access to the state constraints and damage level. DEWEY : 624 ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/abs/10.1080/19648189.2012.667204 [article] Structural monitoring : Identification and location of an impact on a structurally dissipating rock-shed structure using the inverse method [texte imprimé] / Z. Boukria, Auteur ; P. Perrotin, Auteur ; A. Bennani, Auteur . - 2012 . - pp. 20-42. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 16 N° 1 (Janvier 2012) . - pp. 20-42 Mots-clés : Inverse  problem  Identification  Location  Transfer  function  Reinforced  concrete  slab  Tikhonov  regularisation  Numerical  model Résumé : In this study we developed an experimental method to identify the impact force on a reinforced concrete slab. A transfer function obtained experimentally between the acceleration response and the force history applied to a point of the structure was used. To regularise the solution obtained with this inverse problem, we used the Tikhonov method. To locate the impact force, we used an experimental method based on the minimisation of an objective function created from the transfer functions between several impact locations, forming a mesh structure, and several measuring points. Characterising the impact means locating the impactor and identifying the load. Meanwhile, a numerical model is developed using Abaqus to characterise impact force, and allow access to the state constraints and damage level. DEWEY : 624 ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/abs/10.1080/19648189.2012.667204

Investigating concentrated leak erosion behaviour of cohesive soils by performing hole erosion tests / Nadia Benahmed in European journal of environmental and civil engineering, Vol. 16 N° 1 (Janvier 2012) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 16 N° 1 (Janvier 2012) . - pp. 43-58 Titre : Investigating concentrated leak erosion behaviour of cohesive soils by performing hole erosion tests Type de document : texte imprimé Auteurs : Nadia Benahmed, Auteur ; Stéphane Bonelli, Auteur Année de publication : 2012 Article en page(s) : pp. 43-58 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Internal  erosion  Piping  Experimental  study  Cohesive  soils  Critical  shear  stress  Rate  of  erosion  Hydraulic  works Résumé : Internal erosion by piping is one of the common causes of failure of embankment dams and dykes. This phenomenon occurs when preferential flow paths develop in the earthfill or foundation; through these water flows, carrying away particles of soil and leading to the formation and the evolution of a continuous ‘pipe’ between the upstream and the downstream side. A series of hole erosion tests were conducted on cohesive soils in order to quantify critical shear stress and the coefficient of erosion: white kaolinite, proclay kaolinite and a hostun sand/proclay kaolinite mixture. The effects of compaction energy, moisture content, degree of saturation and the percentage of fines were investigated. The experimental results show that these parameters play a key role in the erosion characteristics. DEWEY : 624 ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/abs/10.1080/19648189.2012.667667 [article] Investigating concentrated leak erosion behaviour of cohesive soils by performing hole erosion tests [texte imprimé] / Nadia Benahmed, Auteur ; Stéphane Bonelli, Auteur . - 2012 . - pp. 43-58. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 16 N° 1 (Janvier 2012) . - pp. 43-58 Mots-clés : Internal  erosion  Piping  Experimental  study  Cohesive  soils  Critical  shear  stress  Rate  of  erosion  Hydraulic  works Résumé : Internal erosion by piping is one of the common causes of failure of embankment dams and dykes. This phenomenon occurs when preferential flow paths develop in the earthfill or foundation; through these water flows, carrying away particles of soil and leading to the formation and the evolution of a continuous ‘pipe’ between the upstream and the downstream side. A series of hole erosion tests were conducted on cohesive soils in order to quantify critical shear stress and the coefficient of erosion: white kaolinite, proclay kaolinite and a hostun sand/proclay kaolinite mixture. The effects of compaction energy, moisture content, degree of saturation and the percentage of fines were investigated. The experimental results show that these parameters play a key role in the erosion characteristics. DEWEY : 624 ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/abs/10.1080/19648189.2012.667667

An experimental study on the strengthening of non-ductile reinforced concrete frames via external shear wall / M. Yasar Kaltakci in European journal of environmental and civil engineering, Vol. 16 N° 1 (Janvier 2012) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 16 N° 1 (Janvier 2012) . - pp. 59-76 Titre : An experimental study on the strengthening of non-ductile reinforced concrete frames via external shear wall Type de document : texte imprimé Auteurs : M. Yasar Kaltakci, Auteur ; Murat Ozturk, Auteur Année de publication : 2012 Article en page(s) : pp. 59-76 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Seismic  behaviour  Cyclic  loading  Strengthening  External  shear  wall Résumé : The most common method for strengthening reinforced concrete frames that have insufficient earthquake resistance is the addition of reinforced concrete (RC) shear walls to the structural system. In recent years, the idea of constructing the shear walls not inside but outside the building was preferred and applied in order to decrease the cost of strengthening processes and without limiting the utilisation of the building. The most important problem of this application is that the architectural requirements of buildings can be hindered because of the shear walls constructed out of the axes; this can be solved by connecting the exterior shear walls to the existing frame using coupling beams and leaving a certain spacing between them. In this study, the contribution of the strengthening method called ‘external shear wall application via coupling beam’ on the behaviour of the existing frame under lateral loading conditions was investigated. For this purpose, one reference frame, one reference shear wall and two frames strengthened with external shear walls using coupling beams were produced and tested under reversed-cyclic lateral loading. The strengthened frames were constructed by connecting the external shear wall to the frame by making RC and steel coupling beam applications to determine the behaviour differences between them. In conclusion, the strengthening method made a considerable contribution to the frame that was insufficient against earthquake effects in terms of lateral load carrying capacity, rigidity and energy dissipation capacity. DEWEY : 624 ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/abs/10.1080/19648189.2012.667672 [article] An experimental study on the strengthening of non-ductile reinforced concrete frames via external shear wall [texte imprimé] / M. Yasar Kaltakci, Auteur ; Murat Ozturk, Auteur . - 2012 . - pp. 59-76. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 16 N° 1 (Janvier 2012) . - pp. 59-76 Mots-clés : Seismic  behaviour  Cyclic  loading  Strengthening  External  shear  wall Résumé : The most common method for strengthening reinforced concrete frames that have insufficient earthquake resistance is the addition of reinforced concrete (RC) shear walls to the structural system. In recent years, the idea of constructing the shear walls not inside but outside the building was preferred and applied in order to decrease the cost of strengthening processes and without limiting the utilisation of the building. The most important problem of this application is that the architectural requirements of buildings can be hindered because of the shear walls constructed out of the axes; this can be solved by connecting the exterior shear walls to the existing frame using coupling beams and leaving a certain spacing between them. In this study, the contribution of the strengthening method called ‘external shear wall application via coupling beam’ on the behaviour of the existing frame under lateral loading conditions was investigated. For this purpose, one reference frame, one reference shear wall and two frames strengthened with external shear walls using coupling beams were produced and tested under reversed-cyclic lateral loading. The strengthened frames were constructed by connecting the external shear wall to the frame by making RC and steel coupling beam applications to determine the behaviour differences between them. In conclusion, the strengthening method made a considerable contribution to the frame that was insufficient against earthquake effects in terms of lateral load carrying capacity, rigidity and energy dissipation capacity. DEWEY : 624 ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/abs/10.1080/19648189.2012.667672

Evaluation of natural pozzolan for use as supplementary cementitious material / Yassine Senhadji in European journal of environmental and civil engineering, Vol. 16 N° 1 (Janvier 2012) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 16 N° 1 (Janvier 2012) . - pp. 77-96 Titre : Evaluation of natural pozzolan for use as supplementary cementitious material Type de document : texte imprimé Auteurs : Yassine Senhadji, Auteur ; Gilles Escadeillas, Auteur ; Hamid Khelafi, Auteur Année de publication : 2012 Article en page(s) : pp. 77-96 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Pozzolans  Strength  activity  index  Setting  time  Heat  of  hydration  Chloride  ion  Durability Résumé : This paper presents preliminary study results on the use of local natural pozzolan (NP) as a mineral addition. The natural pozzolan was obtained from a source in north-western Algeria and was composed of zeolite and plagioclase, which are mineralogical materials containing large quantities of SiO2 and Al2O3. A number of cements were prepared in which portland cement (OPC) was replaced by NP in the range of 0–25%. The parameters investigated included pozzolanic activity, setting times, heat of hydration, compressive strength, and the crystalline hydration products (by XRD).The pozzolanic activity index was evaluated on the basis of physical and mechanical parameters (standards ASTM C618 and ASTM C311) and through a chemical analysis (European standard NF EN 196-5). The performance of natural pozzolan cement exposed to aggressive solutions (sulphuric and nitric acids) and their resistance to chloride permeability were also analysed. DEWEY : 624 ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/abs/10.1080/19648189.2012.667692 [article] Evaluation of natural pozzolan for use as supplementary cementitious material [texte imprimé] / Yassine Senhadji, Auteur ; Gilles Escadeillas, Auteur ; Hamid Khelafi, Auteur . - 2012 . - pp. 77-96. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 16 N° 1 (Janvier 2012) . - pp. 77-96 Mots-clés : Pozzolans  Strength  activity  index  Setting  time  Heat  of  hydration  Chloride  ion  Durability Résumé : This paper presents preliminary study results on the use of local natural pozzolan (NP) as a mineral addition. The natural pozzolan was obtained from a source in north-western Algeria and was composed of zeolite and plagioclase, which are mineralogical materials containing large quantities of SiO2 and Al2O3. A number of cements were prepared in which portland cement (OPC) was replaced by NP in the range of 0–25%. The parameters investigated included pozzolanic activity, setting times, heat of hydration, compressive strength, and the crystalline hydration products (by XRD).The pozzolanic activity index was evaluated on the basis of physical and mechanical parameters (standards ASTM C618 and ASTM C311) and through a chemical analysis (European standard NF EN 196-5). The performance of natural pozzolan cement exposed to aggressive solutions (sulphuric and nitric acids) and their resistance to chloride permeability were also analysed. DEWEY : 624 ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/abs/10.1080/19648189.2012.667692

Experimental geomechanics / Mohamed Aris in European journal of environmental and civil engineering, Vol. 16 N° 1 (Janvier 2012) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 16 N° 1 (Janvier 2012) . - pp. 97-110 Titre : Experimental geomechanics : A laboratory study on the behaviour of granular material using bender elements Type de document : texte imprimé Auteurs : Mohamed Aris, Auteur ; Nadia Benahmed, Auteur ; Stéphane Bonelli, Auteur Année de publication : 2012 Article en page(s) : pp. 97-110 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Granular  materials  Microstructure  Inherent  and  induced  anisotropy  Triaxial  test  Bender  elements Résumé : On the basis of three methods of preparing well-differentiated triaxial Hostun HN31 sand specimens, namely moist tamping, dry pluviation and water pluviation, we highlight the influence of the reconstitution mode on the mechanical behaviour of sand. Piezoelectric transducers (bender elements) were installed in a triaxial cell and at the lateral edges of the sample in different directions (HH and HV) to investigate the structural anisotropy caused by each deposition mode and its evolution during undrained shearing tests, by measuring shear wave velocities. The results confirm and enrich the observations made with the scanning electron microscope and triaxial apparatus used by Benahmed, 2001; Benahmed, Canou & Dupla, 2004 on loose sand prepared using two different reconstitution procedures. DEWEY : 624 ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/abs/10.1080/19648189.2012.668031 [article] Experimental geomechanics : A laboratory study on the behaviour of granular material using bender elements [texte imprimé] / Mohamed Aris, Auteur ; Nadia Benahmed, Auteur ; Stéphane Bonelli, Auteur . - 2012 . - pp. 97-110. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 16 N° 1 (Janvier 2012) . - pp. 97-110 Mots-clés : Granular  materials  Microstructure  Inherent  and  induced  anisotropy  Triaxial  test  Bender  elements Résumé : On the basis of three methods of preparing well-differentiated triaxial Hostun HN31 sand specimens, namely moist tamping, dry pluviation and water pluviation, we highlight the influence of the reconstitution mode on the mechanical behaviour of sand. Piezoelectric transducers (bender elements) were installed in a triaxial cell and at the lateral edges of the sample in different directions (HH and HV) to investigate the structural anisotropy caused by each deposition mode and its evolution during undrained shearing tests, by measuring shear wave velocities. The results confirm and enrich the observations made with the scanning electron microscope and triaxial apparatus used by Benahmed, 2001; Benahmed, Canou & Dupla, 2004 on loose sand prepared using two different reconstitution procedures. DEWEY : 624 ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/abs/10.1080/19648189.2012.668031

Experimental analyses of the behaviour of saturated granular materials during axisymmetric proportional strain paths / Mohamad Jrad in European journal of environmental and civil engineering, Vol. 16 N° 1 (Janvier 2012) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 16 N° 1 (Janvier 2012) . - pp. 111-120 Titre : Experimental analyses of the behaviour of saturated granular materials during axisymmetric proportional strain paths Type de document : texte imprimé Auteurs : Mohamad Jrad, Auteur ; Beena Sukumaran, Auteur ; Ali Daouadji, Auteur Année de publication : 2012 Article en page(s) : pp. 111-120 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Triaxial  test  Proportional  strain  test  Instability  Second  order  work  criterion  Static  liquefaction Résumé : Instability of granular materials is usually studied using undrained triaxial compression tests or constant shear drained tests. These tests are usually performed on fully undrained or fully drained samples respectively. In this paper, experimental investigations of the behaviour of loose saturated sand under proportional strain paths performed by imposing a partial drainage condition are presented. Partially drained conditions observed in situ are due to potential pore pressure variations. Different drainage condition changes can lead to different stress–strain responses, and it is shown that the strength mobilisation for expansive drainage conditions is lower than what is usually obtained for undrained conditions. The stability analyses based on experimental results have shown that the second order work criterion, rewritten using the relevant control parameters, is a good tool to investigate the onset of instability. DEWEY : 624 ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/abs/10.1080/19648189.2012.666900 [article] Experimental analyses of the behaviour of saturated granular materials during axisymmetric proportional strain paths [texte imprimé] / Mohamad Jrad, Auteur ; Beena Sukumaran, Auteur ; Ali Daouadji, Auteur . - 2012 . - pp. 111-120. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 16 N° 1 (Janvier 2012) . - pp. 111-120 Mots-clés : Triaxial  test  Proportional  strain  test  Instability  Second  order  work  criterion  Static  liquefaction Résumé : Instability of granular materials is usually studied using undrained triaxial compression tests or constant shear drained tests. These tests are usually performed on fully undrained or fully drained samples respectively. In this paper, experimental investigations of the behaviour of loose saturated sand under proportional strain paths performed by imposing a partial drainage condition are presented. Partially drained conditions observed in situ are due to potential pore pressure variations. Different drainage condition changes can lead to different stress–strain responses, and it is shown that the strength mobilisation for expansive drainage conditions is lower than what is usually obtained for undrained conditions. The stability analyses based on experimental results have shown that the second order work criterion, rewritten using the relevant control parameters, is a good tool to investigate the onset of instability. DEWEY : 624 ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/abs/10.1080/19648189.2012.666900

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