
Ahmed BenamarFrench National Centre for Scientific Research | CNRS · LOMC UMR 6294 CNRS-Université Le Havre-Normandie
Ahmed Benamar
Doctor of civil Engineering
About
90
Publications
14,782
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1,197
Citations
Introduction
Investigation of earth dams susceptibility to internal erosion.
Effect of internal erosion on slope stability.
Remediation and benefit reuse of dredged sediments
Additional affiliations
January 1993 - November 2019
January 1994 - present
Université Le Havre Normandie
Position
- Professor (Associate)
Education
November 1988 - July 1992
Publications
Publications (90)
Laboratory experiments are crucial for understanding scour around embedded structures. However, there is currently no standard and reliable instrumentation for monitoring the progression of this physical process in laboratory. In this paper, the capability of a novel 3D structural-light scanner technique to continuously measure the scour bed topogr...
Global warming (due to climate change) can lead to a decrease in rate precipitations after a long dry season (due to high temperature). Therefore, it can have an effect on the soil properties (due to the evaporation of the water contained in the soil). This modification on soil properties raises a question of how such hydraulic structures (dams and...
In order to assess the capability of a filter skeleton to retain flowing particles transported from eroded soil, different models based on continuous or discrete medium are available. The porous medium is often described by the grain size distribution, whereas constriction size distribution (CSD) is the key parameter governing the filtration proces...
Laboratory experiments constitute an essential part of scour investigation in the vicinity of embedded structures. Yet, no standard and robust instrumentation for monitoring the development of this physical process during laboratory tests is available. In this technical paper, a Laser Scanner has been tested to follow local scour around a circular...
Global warming (due to climate change) can lead to a long dry season (due to high temperature) and decrease in rainfall rates, which may threaten the vulnerability of earthen dams by reducing their resistance to internal erosion. This research investigated the susceptibility of three zoned dams in Morocco to internal erosion, after the dam’s core s...
Mixtures of clay and sand suspended in water are complex systems encountered in many industrial and environmental applications, but their understanding and modelling are still limited and require further investigations. In this way, the rheological behaviour of pure non-thixotropic clay and coarse-grained clay suspensions is investigated with a rot...
The climate change, including very long dry seasons, can threaten the vulnerability of dams and dikes by reducing their resistance to internal erosion. Therefore, it is questionable how long the degradation of soil properties can affect the life of hydraulic structures. This research aims to investigate the internal erosion susceptibility of many e...
Pollution of sediments in harbors originates from several sources due to both past and present human and industrial activities. Pollutions often have a complex composition of a wide variety of organic and inorganic pollutants. When remedial actions include dredging, there is a need to manage and possibly treat sediments. Electrokinetic remediation...
Internal erosion of dam’s embankments is a complex process and considered as the main cause of hydraulic works failure. Laboratory experiments provide a potential insight into the processes involved. Particles detachment from a core of earth and rock fill dams within a crack submitted to water seepage may lead to backward erosion which gradually pr...
Laboratory tests on internal erosion of cohesionless soils are often performed on cells submitted to a controlled seepage. The cell dimension depends on the grain size of tested soil and must meet the geometric and hydraulic scale requirements as regards to the modeled process. Three specimens collected from different zoned dams in Morocco were cha...
In order to maintain a required water depth and to allow waterways navigable, dredging operations are of a great importance. So, large volumes of sediments are annually dredged in the ports over the world. In Le Havre harbor the annual dredged volume of sediments is close to 1.5 Mm3, which are mainly dumped at sea. Because of its perpetual availabi...
Salinization affects ecosystem biodiversity, human health, agricultural productivity, as well as engineering and construction infrastructure. In Algeria, many arid, semi-arid, and near-coastal areas are suffering from soil salinization for more than two decades. In order to restore contaminated soils (saline), the electrokinetic process was tested...
A simple, efficient matrix solid phase dispersive extraction (MSPD) method was optimized to analyse simultaneously polycyclic aromatic hydrocarbons (PAHs) and polychlorobiphenyls (PCBs) from sediments, and was compared to microwave-assisted extraction (MAE). New dispersing agents were tested to improve MSPD extraction. 3-chloropropyl-bonded silica...
The climate change including very long dry seasons can threaten vulnerability of dams and dikes by reducing their resistance to internal erosion. It is, therefore, questionable how long degradation of soil properties can affect the operating life of hydraulic structures. This research is devoted to investigate the susceptibility to internal erosion...
The Miocene marls or calcareous clay of the southern Rif groove is one of the geological wealth of the region of Taza in Morocco. This study presents a methodology for recycling the waste iron oxide in ceramics bricks, in a cost-effective and environmentally friendly manner, using the tailings produced from iron mines. Due to its iron oxide content...
This research aims to investigate the susceptibility to internal erosion of Mazer earthen dam in Morocco under the drying effect causing desiccation due to the threats posed by the drought in North Africa. For this purpose, many erosion–filtration tests have been conducted on samples collected from core soil and downstream filter of the zoned earth...
Most of electrokinetic remediation (EKR) reported researchs were performed on small-scale laboratory devices and less field-scale studies are available in literature. Understanding the scaling-up process is essential for the application of the EKR at field scale. This paper presents the results of laboratory experiments performed at two scales (inv...
The maintenance of harbor waterways generates large amounts of dredged sediments which can be contaminated. These sediments are inappropriate for disposal at sea and are generally stored in coastal on-land disposal sites. But fine-grained sediments involve very high moisture content and very low hydraulic conductivity, which cause natural or mechan...
The Miocene marl (MM) or calcareous clays in the southern Rif groove is one of the geological resources located in the region of Taza (Morocco). The aim of this work is to investigate the use this widely available raw material as an alternative resource in the heavy clay industry. For this purpose, physical, chemical (X-ray fluorescence, XRF), mine...
Electrokinetics is a development technology used for the removal and extraction of contaminants, such as: heavy metals, radionuclides and organic contaminants from fine-grained and low-permeability soils. The goal of electrokinetic remediation is to perform the migration of contaminants under the application of an electric field imposed on two elec...
In this study, we have proceeded to mixing the Miocene marls from quarry of Benjalik with
cement at varying proportions in order to making bricks and we used the Portland cement in
the formulation for their stabilization.
Therefore, the manufacture of a strong brick with low cost seems to be an important
opportunity for industrials and well con...
The Miocene marls or calcareous clays of the southern Rif groove are one of the geological
wealth of the region of Fez in Morocco. The objective of this study is to enhance the physico‐
mechanical characteristics of Miocene marl. Physical and chemical characterization of this
marls was carried out before and after doping with Al2O3 following vari...
Electrokinetic (EK)remediation is often developed for metal decontamination but shows limitations for polycyclic aromatic hydrocarbons (PAHs)and polychlorobiphenyls (PCBs)which are nonionic and involve low aqueous solubility. This paper reports many laboratory studies devoted to the investigations of EK efficiency on the mobility and the removal of...
The construction of embankments and other earth hydraulic structures using coarse soils requires assessing their potential for internal erosion by suffusion, defined as detachment and transport of fine particles through the matrix constrictions under internal flow. For potentially erodible coarse soils containing a certain amount of clays, a possib...
Soil salinization is a problem in many parts of the world, particularly in arid and semi-arid areas. Salinity continues to be a major form of land degradation and a significant environmental threat. The deleterious effects of salinity extend over a broad spectrum that includes productive farmland, ecosystems, river systems and infrastructure. This...
The maintenance of harbor waterways generates large amounts of dredged sediments which contain organic and inorganic contaminants. Electrokinetic (EK) remediation is often developed for metal decontamination but shows limitations for polycyclic aromatic hydrocarbons (PAHs) which involve low aqueous solubility. Laboratory studies were devoted to the...
Given the increasing exploitation of clay in Morocco for ceramic industry and for the purpose of the benefit reuse of this resource, a study is conducted in order to carry out the identification and characterization of Miocene clay after doping with pozzolan. The objective of this work is to improve the physicalchemical characteristics of Miocene c...
Citric acid (CA), a widely used eco-friendly electrolyte, can be employed as an agent for enhancing toxic metal (TM) removal from contaminated dredged sediment using electrokinetic (EK) technology. In this study, dredged harbor sediments co-contaminated by TMs were subjected to enhanced EK treatment using a mixture of chelating agent (CA) and surfa...
The diagnostisis and the expertise of small dams are both important tasks in the assessment of their vulnerability to natural hazards (earthquake, rainfall, snow, wind). In many emergency situations, after an earthquake or a major flood, the diagnostic task requires at the same time quickness and efficiency. But, hydraulic works owners face experts...
Given the increasing exploitation of clay in Morocco for ceramic industry and for the purpose of the benefit reuse of this resource, a study is conducted in order to carry out the identification and characterization of Miocene marl after doping with pozzolan. The objective of this work is to improve the physicochemical characteristics of Miocene ma...
Aquatic ecosystems are precious ecological resources that cover almost 70% of the earth’s surface, and are key targets of European resource management policies. Coastal zones offer many advantages in terms of fishing, maritime transport and tourism. These reasons explain why about 3 billion people live within 200 km of coastline; this represents al...
Electrokinetic (EK) remediation can be a suitable technology for treating contaminated dredged harbor sediment, stored on terrestrial disposal sites. Citric acid (CA) and biosurfactants (rhamnolipids and saponin) were chosen as enhancing agents for simultaneous metal (Cd, Cr, Cu, Pb, Zn) and PAH/PCB removal by EK because of their potential low toxi...
Given the increasing exploitation of clay in Morocco for ceramic industry and for the purpose of the benefit reuse of this resource, a study is conducted in order to carry out the identification and characterization of Miocene marl after doping with pozzolan. The objective of this work is to improve the physicochemical characteristics of Miocene ma...
The marl's minerals are abundant untreated material in several areas worldwide. They are often under-valued for human use. However, due to demands of the society in terms of sustainability and energy saving, the valuation of these resources to develop new materials, most environmentally friendly has become a concern both scientific and industrial a...
The Highway Development and Management 4 (HDM-4) model was developed by the World Bank and used for pavements management system. An approach of the adaptation to local conditions is therefore required by adjusting the calibration factors, with the consideration of the context in which they are to be applied. The aim of the present work is to sugges...
The marl's minerals are abundant untreated material in several areas worldwide. They are often under-valued for human use. However, due to demands of the society in terms of sustainability and energy saving, the valuation of these resources to develop new materials, most environmentally friendly has become a concern both scientific and industrial a...
This paper focuses on the experimental and analytical study devoted to internal erosion (suffusion) of sand-clay mixtures made of different fines contents and tested under head controlled flow. The investigations aim to evaluate a simplified analytical model using experimental results obtained from laboratory column tests. The analytical model is b...
The suffusion phenomenon occurs when fine soil particles are detached by seepage flow and transported away from the matrix. This process is one of the main causes of failure of hydraulic structures and road embankments. This study aimed to build a numerical model for simulating the suffusion within a porous medium. This model combines a flow law an...
In recent years, electrokinetic (EK) remediation method has been widely considered to remove metal pollutants from contaminated dredged sediments. Chelating agents are used as electrolyte solutions to increase metal mobility. This study aims to investigate heavy metal (HM) (As, Cd, Cr, Cu, Ni, Pb and Zn) mobility by assessing the effect of differen...
Dredging practices constitute a challenge for developing and maintaining harbor and fluvial activities because of the bound pollutants as heavy metals, PAHs, etc. Dewatering processes is of important consideration in reuse of sediments by easy maneuverability and low cost transport. A low cost method as mechanical compaction is the more used to red...
Internal erosion takes place when water that seeps through the soil carries fines particles away from the embankment or foundation of dams. The influence of reservoir water chemistry on the detachment and transport of particles is of great importance. So, salinity change in retained water after a flood event can substantially affect the progress of...
Sand-silt-clay mixtures can be used as fill materials and as core materials in earthen structures (dams, dykes). This paper reports results obtained from permeameter tests involving unidirectional seepage through specimens of several widely graded cohesionless soil samples collected from an homogeneous earth fill dam in England. The onset of suffus...
Internal erosion has long been a major problem associated with earthen structures, and its field investigation has been limited because of its complexity. Laboratory experiments provide a potential insight into the induced processes. Soils suitable to suffusion involve an easy movement of fine particles between the coarse ones. In this study, suffu...
La présente étude rentre dans le cadre de l’expertise relative à la remontée des eaux souterraines au niveau d’une plate-forme de construction de bâtiments à usage d’habitation dans une école de formation, située à l’ouest d’Alger (Algérie). Pour assurer la protection de la zone d’habitations, il est nécessaire de dimensionner et d’implanter un sys...
The maintenance of harbor waterways generates large amounts of dredged sediments which are often rich in coexisting organic and inorganic contaminants. Electrokinetic remediation treatments have recently been developed for the simultaneous removal of heavy metals and polycyclic aromatic hydrocarbons (PAHs), using various enhancing agents generally...
The transport and filtration behaviour of fine particles (silt) in columns packed with sand was investigated under saturated conditions by using step-input injections. Three samples of different particle size distributions (coarse medium, fine medium and a mixture of both) were used in order to highlight the influence of the pore size distribution...
This study focuses on the use of a remediation process to remove particle-bound recalcitrant pollutants (heavy metals) from dredged harbor sediments which must be previously treated before reuse in civil engineering. Electrokinetic (EK) remediation is generally accepted as one of the most suitable technologies for extracting cationic heavy metals f...
Solid particle detachment, transport and deposition in natural or artificial porous media have been the subject of an intense
research effort in the last four decades. Particle-facilitated contaminants transport, accidents due to internal erosion in
the hydraulic structures and permeability decreases of the oil wells, drinking water supply or artif...
Increasing demand for water, particularly in arid and semi-arid regions of the world, has shown that the extended groundwater
reservoirs are invaluable for water supply, and storage by recharge becomes essential. In many areas of the world, aquifers
that supply drinking-water are being used faster than they recharge. The overexploitation of groundw...
Ultrasound transmission and reflection are utilized to characterize the particle retention in depth of fluid-saturated porous samples under a flow of silt solution. The effect of the concentration of particles in the fluid is investigated via measurements of "comparison coefficients" which are the ratio of the Fourier transforms of the reflected (t...
Dredging is necessary for the development of the harbours and the maintenance of their activities. Dredging sediments, when polluted, present an effective and durable contamination risk of the ecosystems. The electromigration process is a promising decontamination technique for removal of ionised or ionisable substances contained in the sediment. A...
Internal erosion has long been a major problem associated with earth structures. Laboratory experiments provide a potential insight into the processes involved. The design of dam embankments is usually based on hydraulic criteria. Some of the hydraulic criteria are based on sediment transport theory where the critical velocities are derived from th...
On étudie la propagation des ondes ultrasonores dans un milieu formé de billes de verre et saturé par une eau dont la turbidité peut être choisie. Les billes sont de même diamètre et le milieu obéit à la théorie de Biot. L'insonation normale est produite par un transducteur de fréquence centrale 100 kHz, plaqué sur la maquette métallique (section c...
La vallée du Sébaou connaît un important développement démographique et socioéconomique. Cependant, la demande en eau ne cesse d'augmenter; toutefois, l’irrégularité et la diminution de la pluviosité ont entraîné une nette réduction des apports.
Parallèlement, l’oued Sébaou subit une dégradation significative de la couche sableuse. Cette diminution...
A laboratory study was undertaken on the transport and the deposition of suspended particles (silt of modal diametre 6µm)
in three columns of different length, filled with glass beads or gravel. Tracer tests were carried out at various flow velocities
by short pulses of a mixture of suspended particles/dissolved tracer. The breakthrough curves were...
This paper presents an experimental study of the transport of suspended particles (SP) in a saturated porous medium, aimed at delineating the effects of pore structure on particle transport and deposition rate. Two porous media (silica gravel and glass beads) and silt SP were used. Breakthrough curves (BTCs) were well described by an analytical sol...
A laboratory study was undertaken to determine the transport and deposition rate of suspended particles in columns of saturated porous media (gravel and glass beads), where the porous media were subjected to steady-state flow. Silt particles with a mode of 14 mu m diameter (used as the suspended particles) and fluorescein (as the conservative trace...
An experimental study which aimed at investigating the transport behaviour of suspended particles in saturated porous media is presented. A short-pulse technique was used for measuring particle recovery and collision efficiencies in two porous media (silica gravel and glass beads). Breakthrough curves (BTCs) were measured on-line and well described...
Une étude expérimentale a été menée sur le transport et la rétention de particules en suspension (limon de diamètre modal 6 3m) dans trois colonnes de longueurs 33, 66 et 100 cm remplies de gravier. Les essais de traçage sont réalisés à différentes vitesses d'écoulement par des injections impulsions du mélange particules en suspension / traceur dis...
We study in this paper the transport and deposition of suspended particles in saturated porous media. Some chromatographic short-pulse tests were performed in a laboratory column with a tracer and two types of suspended particles. A mathematical model was used to determine the hydrodispersive parameters and deposition rates from the breakthrough cu...