Search

Coarse-grained soils are a type of soil frequently found in civil engineering projects, and their mechanical characterization still presents a real challenge. They are composed by elements of different dimensions (from a few microns to tens of centimeters), and can be of very varied nature (clay, sand, gravel, pebbles, etc.). The mechanical characterization of coarse-grained soils is very difficult because of the presence of large elements. In order to be able to characterize them in the laboratory by means of conventional size devices, it is very important to study the influence of significant parameters on the mechanical behavior of coarse-grained soils (the volume fraction, particle size distribution and spread, consolidation level and initial state of the matrix), using the large-sized triaxial testing device. In this paper, we will propose a methodology for evaluating the mechanical characteristics of coarse-grained soils based on soil granulometric reconstruction procedures. The method we have named GALA is based on the use of polynomial correlations between the strength increase due to inclusions and the volume fraction fv and the particle spread (dmin/dmax) of inclusions. We were able to apply this new method to a natural soil. The results showed the relevance of our method.

Thermal insulation in buildings has gained significant attention recently due to the clear benefits of selecting appropriate insulation materials for energy conservation. This study presents experimental research conducted to evaluate the thermal properties of mortar based natural Moroccan pozzolan and fly ash, both of which serve as alternatives to cement powder. Unlike cement, which requires energy-intensive extraction, natural pozzolan is an abundant volcanic material, and fly ash is a powdery residu generated as a byproduct during the combustion of coal in thermal power plants. The aim of this research is to explore the potential of these materials for thermal insulation and to address the environmental concern of plastic waste management through recycling. Twenty different mortar mixes were synthesized and evaluated, with a constant 10% of fly ash and varying percentages (10%, 20%, 30%, 40%) of natural pozzolan replacing cement. Additionally, 1% of plastic fibers based on the mortar volume were included. Thermal conductivity and heat capacity of the cured mortar mixtures were measured after 7 and 14 days using a TPS1500 hot disc Analyzer, which is currently the most precise and useful method for studying thermal transport parameters. To ensure consistent conditions, all samples were preconditioned to eliminate moisture before testing. The test results indicated the potential of using plastic fibers, fly ash, and natural pozzolan as effective thermal insulation materials. These materials demonstrated reduced thermal conductivity and increased specific heat capacity, making them desirable for building applications. From an economic and environmental standpoint, incorporating them as cement substitutes for sustainable cement production in thermal insulation is the most favorable approach.

The deformation and failure mechanisms on slopes and in particular the excavations, are very complex. Slope stability analysis is performed using two types of methods: analytical and numerical, which are compared in this article to evaluate their efficiency. The excavation object of this study is situated on the high-speed line between Kenitra and Tangier, specifically in the rural commune of Hjar Nhal, Tangier-Tetouan-Al Hoceima region. It extends for a 1170 m length, its maximum height is 62 m at the axis. The soil of the site is characterized by pelitic formations with the existence of numerous water sources at the base of the excavation. Modelling by analytical methods showed that the excavation did not present a stability problem, contrary to numerical modelling. Firstly, the analysis of the results shows that before the failure, the soil is continuous and that its behaviour cannot be analysed by analytical methods, because a fracture surface cannot be established. It is then necessary to consider numerical methods that take into account the entire volume to analyze the movements and their evolution over time. Secondly, hypotheses have been made about the possibility of a poor estimation of the mechanical characteristics of the soils that constitute the excavation. The review of geotechnical investigations has shown that these soils are coarse with discontinuities that favour water infiltration, and are difficult to characterize, which can lead to an overestimation of their mechanical characteristics.

Several methods are proposed for improving the slopes stability. We are studying the use of a new technique: concrete lozenges channels. The objective of this technique is to stabilize the slope against water erosion. In addition, it makes it possible to combine both mechanical protection with concrete lozenges channels and protection by plant engineering techniques with plants adapted to the area. The present study is part of the continuation of a parametric study whose purpose was to define the optimal design of concrete lozenges channels. Using the finite element method, the purpose is to study the geotechnical stability of a slope stabilized by said lozenges and to define their constructive arrangements.

In a world context focused on energy efficiency and sustainable construction, returning to the use of raw earth in construction constitutes a good alternative to concrete construction, a system more energy consuming and yet more used nowadays. This return is justified by the excellent energy performance and the high level of thermal comfort provided by earth constructions in different climates. In cold climates, adding an insulation on earth walls has proven to be effective in improving their thermal performances. However, the influence of adding an insulation on the energy performance of rammed earth buildings in hot and arid climates remains to this day little explored. The present work comes in this order of ideas; it is based on a comparative study of the energetic performances of a mud building before and after the addition of the insulation. In order to compare between their performances, we have performed a simulation of the thermal behaviour of each by the dynamic thermal simulation software Design Builder.

Liquefaction is a hazardous and temporary phenomenon by which water saturated soil loses some or all of its resistance. The undrained conditions linked to the cyclic load increase the pores water pressure inside the soil and consequently reduce effective stress. As a result, the soil can no longer resist or hold the shear forces, and lead to enormous deformations that directly influence the stability of structures and infrastructures foundations. Since 1964, several semi-empirical methods have been invented to evaluate the liquefaction potential using the in-situ test results. This study is based on the correlation between experimental data results of Menard pressuremeter and SPT dynamic penetrometer tests. Samples used in this test come from the Rhiss dam located in the North of Morocco, 24 kilometers as the crow flies from the town of Al Hoceima and south of the foundations of a calcareous ridge. The studied area have high seismic activity and a high percentage of fine soil elements, which suggests the possibility of soil liquefaction. We present and discuss the results of applying Idriss and Boulanger, and Youd et al methods in the evaluation of liquefaction susceptibility.

The use of different types of recycled plastic waste such as recycled polypropylene (PP), recycled low-density polyethylene (LDPE) and recycled polystyrene (PS), as raw materials for bitumen modification is known. However, the mechanical and thermal properties of recycled plastic waste modified bitumen (RPMB) are lower than those of the pure plastic modified bitumen. Therefor this paper aims to study the mechanical and thermal properties improvement of the RPMB with the use of a commercial elastomer styrene-butadiene-styrene (SBS). Initially conventional 35/50 quality bitumen was mixed with different percentages of LDPE, PS and PP, and then doped with commercial SBS. Basic rheological parameters such as penetration, softening point, elastic recovery and penetration index showed the changes caused by each rate of polymer addition to pure bitumen. The tests showed that the penetrability of the modified bitumen decreases and its softening point and elastic recovery increases, resulting in a decrease in the thermal sensitivity of the new bitumen mixture.

The evaluation of historical buildings has always posed significant challenges due to the difficulties associated with the characterization of complex geometries, the variability of the properties of building materials and the actual state of damage to these structures. This challenge is even more complex when it concerns historical adobe masonry buildings, because earthen masonry has a high variability and rapid deterioration over time if it is not properly maintained. In the context of the previous, it was important to provide information to support intervention projects in historic centres. This research involves the experimental analysis of the adobe material collected from the Chellah archaeological site (Rabat-Morocco), in order to study the mechanical behaviour of this material as well as that reinforced by wood shaving. A series of mechanical tests carried out, which include compressive and tensile strength on the adobe material and the mixture adobe/wood fibre in different proportions. The improvement of the mechanical properties of the reinforced adobe, led us to a SEM study, which was carried out on the surface of the test specimens to examine the morphology and observe the interfaces of the adobe/wood mixture, as well as the state of dispersion of the fibres in the adobe mixture.

Caused by earthquakes in the marine environment, tsunamis are often of particular violence. Pests, their damage far exceeds those caused by earthquakes earthquakes. In Morocco, seismic sensors in the national network often detect earthquakes in the marine environment. However, specialists minimize their threat given the peculiarity of the Moroccan ocean zone. The latter is characterized by the importance of the length of the faults and the depth of the seismic focus. This work can be considered as a first approach to the study and understanding tsunamis. Although Morocco has known since historical times, earthquakes and tsunamis along its coasts. This preliminary study is mainly intended to show the contribution of the numerical simulation of tsunamis, with a concrete application of the 1755 Tsunami of Lisbon based on the four source zones involving the five potentially tsunamigenic faults that are generally mentioned in the literature for this major event.

Liquefaction is a hazardous and temporary phenomenon by which a soil saturated with water loses some or all of its resistance. The undrained conditions and a cyclic load increase the pores water pressure inside the soil and therefore a reduction of the effective stress. Nowadays many semi-empirical methods are used to introduce a proposition to evaluate the liquefaction's potential using the in-situ test results. The objective of this paper is to study their ability to correctly predict the liquefaction potential by modelling our case using finite element methods. The study is based on the data of Cone Penetration Tests experimental results of the Casablanca-Tangier High-Speed Line exactly between PK 116 + 450 and PK 116 + 950 and near of Moulay-Bousselham city. It belongs to the Drader-Soueir basin region which is located in the North-West of Morocco. This region had a specific soil’s formation, the first 50 meters are characterised by the existence of sand layers alternating with layers of clay. These formations are very loose and saturated which suggests the possibility of soil liquefaction. We present and discuss the results of applying the Olsen method [1], the Juang method [2] and the Robertson method [3], in the evaluation of liquefaction susceptibility. Apart from the previous empirical analysis to evaluate the liquefaction potential, numerical modelling is performed in this study.

The use of finite element analysis has become widespread in geotechnical practice as means of optimizing engineering tasks; it can be easily applied to the treated areas by stone columns, which are a method of improving the soil having low geotechnical properties and likely to deform significantly under load action, by incorporating granular material (commonly called ballast) compacted by remounting passes, so they act mainly as inclusions with a higher stiffness, shear strength than the natural soil. Moreover the stone columns are highly permeable and act as vertical drains facilitating consolidation of the soft soil improving the performance of the foundation. However the characteristics of this granular material influence the behavior of soft soils treated by the stone columns technique, especially: the friction angle, the cohesion, the modular ratio and the constitutive model. The choice of the constitutive model depends on many factors but, in general, it is related to the type of analysis that we intend to perform. Numerical modeling must consider the diversity of the materials nature, the complex geometry of structures-land and the behavior of materials generally nonlinear (permanent deformation). It is a simple and effective alternative to approach the real behavior of soils reinforced by stone columns and the influence of materials characteristics, it allows settlement analysis, lateral deformation, vertical and horizontal stresses in order to understand the behavior of columns and soil. It also has the advantage of integrating the settlements of the underlying layers. This paper aims to study the mechanisms of functioning and interactions of stone columns with the surrounding ground, and vis-à-vis the various parameters characterizing the granular material "ballast" and the surrounding soil, which influence the behavior of the improved soil, The paper presents, in the first part, soil conditions and the parameters associated with columns, is then presented 3D finite element analyses, so the parametric study was carried out varying several properties especially granular material properties.

The earthquakes are abrupt and sudden, and, in few seconds, they can lead to huge casualties. Nowadays, several approaches can be used to better know the seismic movement than we can expect when and where will have an earthquake. These approaches kind, always begins with a full study of the seismic action: the seismic birth, the wave formation and propagation, accelerometers and associated spectrum representation, etc. The northern region in Morocco has an important seismic activity, indeed, this region has been struck during its history by many destructive earthquakes. In this paper, we present and discuss the Mediterranean earthquake, January 25, 2016, saved in ZGH station located in Zeghanghane near of Nador city, Morocco. In this case, we determine the spectral response of the ground motion for ZGH station, and study his influence on the structures as well as make a comparison with the requirements of the Moroccan seismic construction regulations (RPS) 2000 revised in 2011.

Masonry is often used in the most of reinforced concrete structure constructions as a filling material that is important on structural characteristics. Structural contribution in the calculations was neglected or misunderstood, mainly due to the lack of a practical calculation methods and an appropriate regulatory tool. The analysis of frames filled with masonry is very complex. This complexity is linked from one part to the difference in the nature of elements and its behavior that make up the masonry itself (brick and mortar) and their interaction, and on the other part, for the large dispersion that characterizes the bricks as well as the execution's quality parameters which make it difficult to define reliable criteria for the masonry. The objective of this work is to experimentally highlight the influence of the hollow brick masonry filler, commonly used in Morocco, on reinforced concrete frames subject to lateral stresses, to deepen understanding the seismic behavior of the masonry structures by evaluating the structural performance of a specimen wall. These experimental results will be compared to those found by modeling prototypes, using SAP 2000 software, based on various approaches and models as well as other results deduced from the other researchers. The experimental study was carried out according to standard NF EN 1052-3 on two reinforced concrete frames, of dimensions (2m X 1.6m), the one with the masonry filling, and the other without filling in order to determine the initial characteristic resistance to the shearing of the masonry walls. The obtained results showed that a filling has a beneficial effect on rigidity which can be doubled compared to an empty frame. in the same way the lateral resistance. But this effect is much contrasted; it depends a lot on the characteristics essentially of the materials (bricks and concrete). This is the main reason, which justifies the divergence of the results deduced from the nine models that we used.

Nowadays, many assumptions hold that returning to rammed earth construction could be a solution to the energy challenges of the time. These assumptions are based on the ability of the material to maintain a comfortable indoor temperature regardless of the outdoor climatic variations. However, its influence on the energy performance of buildings remains little explored so far. This paper comes in this order of ideas. It is devoted to study and evaluate the energy efficiency of rammed earth buildings compared to those in concrete structure and masonry envelope. It takes as case study two buildings: one is traditional, entirely built with the technique of rammed earth; the other is constructed of concrete. In order to compare between their performances, we have performed a simulation of the thermal behavior of each by the dynamic thermal simulation software Design Builder.

Water erosion is a natural phenomenon, the severity of which is related to several parameters depending on the raindrop impact, the characteristics of the soil and the level of human intervention. The risk of water erosion occurs in both drainage basins and road and rail slopes. Indeed, this phenomenon can be aggravated causing major gullies and landslides. The PK 94 of the Taourirte-Nador railway line, located in the oriental region of Morocco, whose slopes are formed by silt-clay formations experiencing intense erosion. The Moroccan experience for the slopes protection of water erosion knows the use of several methods in particular; concrete arcades and methods based on biological engineering. The objective is to contribute to this subject by proposing the use of concrete lozenges technique. It have the advantage of reducing both the area at risk of erosion and especially the length of slope which is an important factor in the Revised Universal Soil Loss Equation RUSLE used to quantify the quantities of soil eroded.

The Soil and subsoil survey are performed by direct and indirect methods. The direct methods are the investigations of field and laboratory while indirect methods are the geophysical methods. These allow, from one or more physical properties, to find out the underground's structure nondestructively. Geophysical methods for characterizing subsurface have long been used, in geotechnical, hydrogeological and environmental studies. For our study, we used the electrical resistivity's method. 52 geoelectric soundings VES was performed with a mesh of 500 m and electrodes distance between 1000 m and 3000 m. The interpretation of these VES allows the determination of the vertical succession of formations in place. In order to have a lateral facies variation, we used geostatistical methods for having adequate data that can be used in the input file of inversion's code Res2Dinv. The 2D images of the subsoil obtained confirm and complement the results of the correlations of oil drilling that are in this region. Thus, the study area also has a horst and graben structure. This study also allowed us to locate the sandstone formations that extend in two places along a North-South direction.

The soil is generally a heterogeneous material presenting very variable characteristics. In a general way, the main problems related to soils are: low bearing capacity, deformations under static or dynamic loads, large displacements and large settlements of soft soil where the soil moves according to a fixed ground water table. The development of soil mechanics and geotechnical engineering has led to the amelioration of a wide range of soil improvement techniques. These techniques consist in modifying the characteristics of the ground by physical action or by incorporating columnar inclusions made of highly compacted gravel or granular material into the original soil. Stone column is one of the soft ground improvement methods, applicable to a wide range of soil strata and an economical method of support in compressible and cohesive soils. However, there are many difficulties in quantitative analysis of soil column interaction due to the fact that bearing capacity and consolidation behavior of stone column-mat foundation system is affected by various parameters. In the present study, mechanism and various parameters of stone column behavior are investigated by loading tests. Also, tests results are compared to the finite element numerical modeling “Plaxis 2D” (case study: the embankment under the bridge “Moulay Youssef, Rabat/Salé”).