Bachir Melbouci - Academia.edu (original) (raw)

Papers by Bachir Melbouci

$Research paper thumbnail of Evolution of the fractal dimension of granular materials in fragmentation tests$

In granular media, breaks occur during compaction. Depending on the shape, strength and compactio... more In granular media, breaks occur during compaction. Depending on the shape, strength and compaction mode, soil grains can be degraded even during the first compaction. When the grains are solid, hard and fairly rounded, they can withstand high stresses that require the use of heavy equipment or compactors in the construction of high earth and rockfill dams to meet high density requirements. On the other hand, the angularly shaped grains of freshly extracted quarry materials endure a fragmentation due to the breaking of asperities under lesser stresses and reach higher densities [1]. A gradual crushing during compaction indicates a gradual change in the void index which subsequently influences the soil carrying capacity. The importance of grain fragmentation may not influence the design and stability of structures. Excessive crushing during compaction will improve the density which should be a consideration in evaluating the benefits of heavier compaction equipment. The advantage of c...

IOP Conference Series: Earth and Environmental Science, 2016

Landslides are a complex natural phenomenon that constitutes a worldwide serious natural hazard. ... more Landslides are a complex natural phenomenon that constitutes a worldwide serious natural hazard. Northern Algeria, as all the Mediterranean countries, suffers by this hazard in many towns (JIJEL, Bejaia, Algiers, Constantine, Mila, Media...). Landslides constitute a significant problem for development and urban planning particularly in the city of Tizi-Ouzou, where after each pluvial season; landslides cause many damages for constructions, soils and human lives. The region of Tizi-Ouzou is situated in an area with a variable geology characterised by the presence of different loose formations, where the landslides are widespread. The inventory map of landslides was constructed by field surveys and historical phenomenon, the number of major and significant landslides considered exceeds 25, scattered all about this region. Our paper aims to present the first inventory map of the major landslides induced by different parameters as lithology, geology, slopes, precipitations, urbanization and seismic activities in this region since 1950. Each landslide will be presented and characterized with different geotechnical and geophysical parameters. The results of this study show the importance of landslides inventory in the region of Tizi-Ouzou, to preserve and reduce the hazard to build in risked region, to save human lives and provide useful tools to take decisions.

$Research paper thumbnail of Study of crushing of grains of limestone under the effect of cyclic loading with the fractal dimension$

Journal of Building Materials and Structures, 2018

The grains can be of very diverse nature (size, shape, mineralogy, etc), indeed even if each grai... more The grains can be of very diverse nature (size, shape, mineralogy, etc), indeed even if each grain is a fairly simple object, the set of grains is a very complex system in which the geometrical and physical properties of the grains, their forces and their orientations play a crucial role in their mechanical behavior. The measurement of their shape in soil mechanics has historically required the use of standards and diagrams to which the different grains can be compared. However, these methods are approaches and remain insufficient and incomplete for the actual measurement of their form and the understanding of their behavior remains a task far from being completed. This work is in this context and proposes to analyze the shape and size of the grains with the fractal theory using the Box Counting method. It also makes it possible to study their influence on the crushing of the grains of the calcareous material under the effect of the cyclic loading-unloading during the oedometer test...

Bulletin of Engineering Geology and the Environment

The behavior of granular materials subjected to shear loading is often very complex to be correct... more The behavior of granular materials subjected to shear loading is often very complex to be correctly characterized. Loads on a discrete medium composed by several grains lead to a diffusion of stresses in the medium by contact and frictions between individual grains. This stress diffusion combined to inter-granular relative movements induces some cracking in the contact zones and even some complete grain crushing. This results in producing other grains of smaller size, changing thus the grain size distribution of the original material and its mechanical behavior law. Quantifying the rate of crushing is of significant importance for understanding the behavior of the granular medium. In the present work, a statistical study of crushing grains in a granular medium subjected to shear load is presented. A probabilistic model using the Weibull distribution is proposed to evaluate the rate of crushed grains as a function of the applied load. The material used in this study are limestone graine of diferent size, produced from crushing of healthy rock. The obtained results showed that the breakage of grains under shear load depends mainly on their dimensions and on the intensity of the applied load. Also, statistical modeling using the Weibull method produced satisfactory adjustment of the experimental data.

Geotechnical and Geological Engineering

International journal of pavement research and technology, Nov 7, 2022

Proceedings of the Third International Symposium on Materials and Sustainable Development, 2018

The experimental study carried out has a dual objective: valorize the clay material in the road a... more The experimental study carried out has a dual objective: valorize the clay material in the road area and improving the bearing capacity of the shaped layers by reinforcement with plastic waste (granules plastic). To do this, six mixtures of clay and sand of different percentages were studied: 100% Clay, 95% Clay + 5% Sand, 90% Clay + 10% Sand, 85% Clay + 15% Sand, 80% Clay + 20% Sand, 75% Clay + 25% Sand. Proctor compaction tests were conducted on mixtures (sand + clay + plastic waste). The results obtained show a clear evolution of the characteristics of the Proctor test according to the different types and percentages of the recycled plastic.

Journal of Building Materials and Structures, 2018

The soil structure can be described as an assembly of elements of various sizes separated by a co... more The soil structure can be described as an assembly of elements of various sizes separated by a complex system of cracks and fractures, since the grains of the soil are differentiated by their shape, size and orientation. They are thus differently associated and related, their masses can form complex and irregular configurations which are in general extremely difficult to characterize in exact geometric terms. To understand the mechanical behavior of granular materials, it is then necessary to characterize the grains using the fractal dimension which is a characteristic that indicates the degree of irregularity and fragmentation of the latter. This experimental work consists in studying the influence of the parameters variation: granular class, grain size and normal stress applied during Casagrande's direct shear tests on the roughness fractal dimension calculated with the method of Box counting. The analysis of the results obtained at the end of a granulometric variation which c...

Cette étude présente une application numérique sur la localisation des déformations qui est un ph... more Cette étude présente une application numérique sur la localisation des déformations qui est un phénomène qui se manifeste sous des sollicitations mécaniques avant la rupture surtout des géo matériaux sous forme de bandes appelées communément bande de cisaillement. Les différentes façons de détections des déformations localisées ainsi que les théories utilisées pour expliquer le passage des déformations homogènes aux déformations hétérogènes qui est parfaitement illustré dans la théorie de bifurcation et ainsi calculer les caractéristiques (orientations et épaisseurs) des bandes de cisaillement. Nous avons simulé numériquement l'essai de cisaillement direct à la boite sous le logiciel Plaxis 8.2 pour définir les paramètres de la bande de cisaillement à savoir sa largeur ainsi que l'angle de son orientation et étudier ces dernières en utilisant les couleurs des contraintes à la rupture qui décrivent le comportement du matériau vu le concept de rupture à une certaine contrainte...

XVIèmes Journées, Le Havre, 2020

Afin d'aborder l'emploi et la valorisation des sédiments de dragage et rentabiliser l'opération d... more Afin d'aborder l'emploi et la valorisation des sédiments de dragage et rentabiliser l'opération de dragage qui s'avère très onéreuse, nous avons étudié le cas des sédiments de l'Oued de la Soummam dans la région de Bejaia au nord d'Algérie. Une étude paramétrique approfondie qui a pour objectif d'utiliser les sédiments de dragage dans le domaine routier a été réalisée. Elle a comme double avantage, d'une part de rentabiliser l'opération de dragage et d'avoir à disposition une grande quantité de matériaux de construction. Comme première étape, nous avons étudié les caractéristiques minéralogiques et physiques des deux échantillons, discuté les performances mécaniques, pour ensuite aborder la possibilité d'amélioration des caractéristiques physico-mécaniques de ces sédiments, permettant ainsi leur utilisation. Cette pré-étude montre qu'il est nécessaire d'améliorer les caractéristiques physiques et le comportement mécanique des sédiments naturels pour répondre aux critères imposés par les réglementations en vigueur. L'effet d'un traitement au ciment seul ou associé à des fines de carrière sur les propriétés des sédiments a été étudié. Différentes formulations sont testées dans le but de répondre aux exigences réglementaires. Ainsi nous avons noté que la portance et la résistance à la compression des sédiments se sont nettement améliorées après traitement et évoluent avec le taux de ciment, comme nous avons noté un effet positif de l'association de fines de carrière sur les mêmes paramètres. Une synthèse des caractéristiques mécaniques obtenues est proposée. Le matériau traité est désormais conforme aux normes exigées en technique routière à partir de 2% de ciment.

European Journal of Environmental and Civil Engineering, 2018

The quantification of the grain's crushing has often been neglected in the past, today it is a ne... more The quantification of the grain's crushing has often been neglected in the past, today it is a necessary asset in the selection of use of granular materials. The Kick and Rittinger theories on energy reduction in the size of a grain combined with the model proposed by Fukumoto who represents mathematically the particle size distributions, allowed us to calculate the area between the grain size distributions curves before and after tests. The aim of this work is to identify the amount of crushed grains on local materials (pegmatite, clayey schist and sandstone) in order to quantify the breaking of their grains. The evolution of the particle size distribution, particle breakage, of these materials was investigated through performing a three series of tests (oedometer, shear and Proctor tests). This grain size spreading obtained after the test, called the crushing surface, shows that the crushing evolves with not only the increase of load, presence of water and grain size, but also with the material (mineralogy) and the stress path.

Geotechnics for Developing Africa, 2021

Les glissements de terrain sont des structures complexes et evolutives, difficiles a caracteriser... more Les glissements de terrain sont des structures complexes et evolutives, difficiles a caracteriser. La region de la Kabylie comme toutes les regions du nord de l'Algerie compte plusieurs sites affectes par ces mouvements. Cette communication a pour objectif l'etude de deux sites de glissements de terrain en grande Kabylie, le premier est le glissementde Tigzirt affectant une zone cotiere distante de 39 Km du chef lieu de la wilaya de Tizi-Ouzou, caracterisee par des flysch etmarnes avec une pente variant de 10 a 15° et le second est le glissement d'Ain El Hammam situe a 50 Km au Sud-Est de laville de Tizi-Ouzou se manifestant dans des terrains metamorphiques de pente raide superieur a 30°. La methoded'investigation geophysique par tomographie electrique a ete appliquee sur ces glissements de terrain afin de caracteriserleurs structures internes. Les profils de resistivites ont permis avec les essais geotechniques de differencier la masse enmouvement du substratum sous...

Geotechnical and Geological Engineering, 2021

The micro-texture of the aggregates of a pavement layer has a direct influence on their resistanc... more The micro-texture of the aggregates of a pavement layer has a direct influence on their resistance. Whatever the position of these aggregates in a pavement structure, they must withstand, during construction or during life, the stresses of attrition and impact. In this study, a series of mechanical tests (Proctor, Los-Angeles and Micro-Deval) are carried out on grains of local materials (limestone and shale), the degree of crushing of the grains has been quantified using the concept of fractal dimension. The fractal dimension was calculated for the different grains constituting the samples before and after each test, with the use of two two-dimensional 2D methods (Masses Method at the scale of a sample and the Box Counting Method at the scale of a grain) and a three-dimensional 3D method (Blanket on a grain scale) which is based on the use of the difference between erosion and dilation. We seek to determine from these methods the correlation between the two fractal dimensions, namely 2D and 3D and study the influence of different parameters on the mechanical characteristics of the materials chosen: the shape and size of the grains, the presence or absence of water, the stress intensity as well as the nature of the material. The results obtained show that the three-dimensional method has a positive effect on the description of the 3D microstructure of the surface of the grains subjected to the various mechanical tests.

Revue Française de Géotechnique, 2006

The im provem ent of m aterials by com paction is directly related not only to the grading of the... more The im provem ent of m aterials by com paction is directly related not only to the grading of the m aterials but also to their grain shape, their angularity and the water content. In this paper, w e present the results of an experim ental study of tw o com paction processes : the Proctor test and the C B R test w ith their influence on the crushing phenom enon of the grains of three schistous local m aterials (argillaceous schist, glossed schist and m ottled schist). This crushing is quantified by two parameters: the coefficient of uniform ity Cu and the rate of crushing B 1 0. These results show that the grains crushing is highlighted by the spreading out of the grading curves w hich evolve according to the energy of com paction. The uniform ity coefficient C u and the factor B 1 0 confirm that this evolution is a function of the size ranges, the water presence and the hardness of the grains.

Bulletin of Engineering Geology and the Environment, 2017

Located at the summits of the mountains of Djurdjura, the mudflow of Illilten has damaged the two... more Located at the summits of the mountains of Djurdjura, the mudflow of Illilten has damaged the two villages, Ait Aïssa Ouyahia and El-Had, located at 70 km to the South East of the chief place of the town of Tizi-Ouzou. This earthflow occurs on two slopes with an average slope of 15% to 45% in the highlands of the Djurdjura in the southeast of the summit of Azrou N'Tohor (1884 m), concerns about 57 ha and mobilises millions of cubic meters of scree and torrential alluvial deposits. It was triggered by the heavy rainfall recorded in 2012, from an altitude of about 1800 m to the foot of Oued Azrou N'Thour up to 900 m altitude. It has a scarp of 300 m in depth and 500 m in width with a thickness varying from 5 to 20 m. This work consists, on the one hand, in seeking the main triggering causes while characterising the materials constituting it through a series of laboratory tests, carried out on remoulded samples extracted upstream and downstream of the earthflow, On the other hand, to study the evolution of this earthflow with a temporal follow-up using satellite image analysis. Résumé Située aux sommets des montagnes du Djurdjura, la coulée boueuse d'Illilten a touché les villages, Ait Aïssa Ouyahia et El-Had, situés à 70 km au Sud Est du chef lieu de la wilaya de Tizi-Ouzou. Cette coulée se manifeste sur deux versants d'une pente moyenne de 15% à 45% dans les hauteurs des montagnes du Djurdjura au Sud Est du sommet d'Azrou N'Tohor (1884 m), elle concerne environ 57 ha et mobilise des millions de mètres cubes d'éboulis et d'alluvions torrentielles. Elle s'est. déclenchée suite à la forte pluviométrie enregistrée durant l'année 2012, depuis une altitude d'environ 1800 m jusqu'au pied de l'Oued Azrou N'Thour à 900 m d'altitude. Elle présente un arrachement sommital de 300 m de profondeur et de 500 m de largeur avec une épaisseur variant de 5 à 20 m. Ce travail consiste, d'une part, à chercher les principales causes de déclenchement tout en caractérisant les matériaux la constituant à travers une série d'essais de laboratoire, effectués sur des échantillons remaniés extraits en amont et en aval de la coulée et d'autre part, à étudier l'évolution de cette coulée avec un suivi temporel à l'aide d'analyse d'images satellitaires.

Bulletin of Engineering Geology and the Environment, 2016

Reuse of dredging sediments has already generated interest and been the subject of a few comprehe... more Reuse of dredging sediments has already generated interest and been the subject of a few comprehensive studies. The dredging of dams and rivers consists in very expensive operations that implement large volumes of materials. The valorization of sediments is an alternative for storage or sea disposal and offers a better environmental solution. Two specific cases of dredged sediment valorizations in the region of Bejaia in Algeria are studied: sediments of Kherrata dam and the Soummam River. Laboratory tests are performed to characterize the dredged sediment according to French standards of geotechnical classification. The characterization shows the need to improve their mechanical behavior, to allow use in the road field. The experimental work on solidification and stabilization sediments, in sublayers of roads is based on a treatment with hydraulic binders: cement or lime. Tests on binder-based sediment material are carried out for ratios of binders between 2 and 15 % of sediment dry weight. The addition of particle-size correctors, sand or quarry fines, is studied in order to reduce the use of lime. The results show the efficiency of treatment with hydraulic binders, in particular with cement. The quarry fines improve the mechanical behavior in the short term for sediment treated with lime.RésuméLe réemploi des sédiments de dragage a fait l’objet de très nombreuses études et travaux. Le dragage des fleuves et barrages représentent des opérations onéreuses qui mettent en œuvre des volumes importants de matériaux. La valorisation des sédiments issus de ces opérations de dragage est une alternative au stockage ou au rejet en mer et offre une solution plus respectueuse de l’environnement. Deux applications spécifiques dans la région de Bejaia en Algérie sont étudiées: cas du barrage de Kherrata et Oued Soummam. Une série d’essais en laboratoire permet de caractériser ces sédiments et de les classer, du point de vue géotechnique selon la norme française. Cette caractérisation montre la nécessité d’améliorer leur comportement mécanique pour permettre une utilisation dans le secteur routier. Un travail expérimental de solidification et stabilisation des sédiments en sous couches routières est mené à base d’un traitement aux liants hydrauliques (chaux ou ciment), les dosages en liant varient de 2 % à 15 % du poids sec des sédiments. L’incorporation de correcteurs granulométriques, sables ou fines de carrière, a été étudié afin de réduire les apports de liant. Les résultats montrent l’efficacité du traitement aux liants hydrauliques, notamment dans le cas du ciment et l’apport de fines de carrière améliore le comportement mécanique à court terme des sédiments traités à la chaux.

Natural Hazards, 2017

The natural hazard assessment is hampered by many difficulties due to the complexity of the pheno... more The natural hazard assessment is hampered by many difficulties due to the complexity of the phenomenon and the need to manage simultaneously several natural and/ or technological hazards. Such is the case of most unstable urban sites in Algeria. The paper presents a risk analysis study of landslides and their reactivation in Tigzirt coastal city, located in the north of Algeria, which is classified in a moderate seismic zone. The spatial techniques based on geographic information systems are used to assess landslide susceptibility and hazard. Two qualitative studies of landslide hazard assessment are conducted using parameters defining the Algerian landslides context. The hazard is evaluated by performing a combination of the landslide susceptibility and the urban density. Earthquakeinduced landslide hazard is assessed taking into account the Algerian seismicity. The study led to determination and mapping of the hazard induced by Tigzirt landslides. Keywords Tigzirt Á Landslide Á Risk Á Vulnerability Á Regional seismicity Á Mapping 1 Introduction Landslides are one of the most catastrophic geohazards that cause severe injuries and property destruction in the north of Algeria. The landslide susceptibility and hazard assessment approaches constitute the fundamental tool for predicting, planning, assessing and mapping the risk. These studies are based essentially on previously observed phenomena and include collecting data, building a spatial database, extracting landslide-related factors, calculating the frequency ratios, overlaying factors, making instabilities

$Research paper thumbnail of Evolution of the fractal dimension of granular materials in fragmentation tests$

IOP Conference Series: Earth and Environmental Science, 2016

$Research paper thumbnail of Study of crushing of grains of limestone under the effect of cyclic loading with the fractal dimension$

Journal of Building Materials and Structures, 2018

Bulletin of Engineering Geology and the Environment

Geotechnical and Geological Engineering

International journal of pavement research and technology, Nov 7, 2022

Proceedings of the Third International Symposium on Materials and Sustainable Development, 2018

Journal of Building Materials and Structures, 2018

XVIèmes Journées, Le Havre, 2020

European Journal of Environmental and Civil Engineering, 2018

Geotechnics for Developing Africa, 2021

Geotechnical and Geological Engineering, 2021

Revue Française de Géotechnique, 2006

Bulletin of Engineering Geology and the Environment, 2017

Bulletin of Engineering Geology and the Environment, 2016

Natural Hazards, 2017