THE EFFECT OF SOIL DENSIFICATION ON THE ATTENUATION OF THE PHENOMENON OF SOIL LIQUEFACTION IN A PORT PROJECT IN MOROCCO

Morocco, which is in a seismically active zone, is currently experiencing a significant development in terms of the realization of development and infrastructure projects. Therefore, reflection on soil liquefaction problems during project design is essential. The densification of soils by vibro compaction is a recent process of soil treatment, its effect is to improve the geo mechanical characteristics of the soil in this case the relative density and subsequently the reduction of the potential for liquefaction, it is a technique soil improvement in the mass, it is closely linked to the grain size of the soil to be treated, its percentage of fines less than 10% (going to 0.08 mm <10%), this technique gives the treated soil sufficient cohesion to avoid large increases in pore pressures during the earthquake. This article aims, through the study of a real case, to evaluate the effectiveness of vibro compaction to improve the relative density of the soil and consequently the reduction of the risk of liquefaction of the treated soil. The work focuses on the analysis of the SPT tests carried out before treatment and on the CPT tests of control of the vibro-compactge works carried out after execution. This study showed that this process generates an effect of improvement of the relative density and reduction of the compaction by inducing a reduction of the risk of liquefactio

Assessment of Liquefaction Potential by Comparing Semi-Empirical Methods Based on the CPT Test

Liquefaction is a dangerous and temporary phenomenon whereby water-saturated soil loses all or part of its strength. Undrained conditions associated with cyclic loading increase water pressure in soil pores, thereby reducing effective stress. The aim of this study is, on the one hand, to report on the phenomenon of liquefaction of sand, clay and silt deposits in more or less water-saturated zones in the section located at the heart of the central alluvial plain of the Oued Sebou in the mio-plioquaternary Gharb basin and, on the other hand, to study the ability of semi-empirical methods to correctly assess liquefaction potential, while specifying the most appropriate method for the area studied. The study is based on data from experimental results of static penetrometer tests between the Mnasra - Ouelad Salama zone in the Oued Sebou alluvial plain of Morocco's mio-plio-quaternary Gharb basin, made up of sandy, sandy-clay, sandy-silt and silty-sandy formations, which are more sensitive to liquefaction due to their saturation and grain size. We present and discuss the results of Olsen's method, Juang's method and Robertson's method, which are based on the CPT static penetrometer test, as well as looking at the impact of dynamic loading and soil structure on liquefaction probability index values

The choice of optimal sites for controlled landfill using the Analytical Hierarchy Process and the Geographic Information System: A case of Oum Azza in Morocco

Depending on the technical, institutional, economic and social limits of developing countries, as well as the population density in cities, nowadays, the volume of urban waste has increased considerably, and the management of this waste contributes to climate change, and air pollution, it directly affects many ecosystems and many species. Waste management faces serious problems such as irregular collection, informal sweeping activities, uncontrolled dumping and proliferation of illegal dumping. The latter constitute a real and permanent threat to the quality of life, this exponential increase in the urban population and the resulting accelerated phenomenon of urbanization have highlighted the need to develop sustainable and efficient waste management systems. Stakeholders are therefore required to consider alternative and available means of disposal, in particular by minimizing the damage caused to the ecosystem and to the human population, among these means of disposal, controlled landfills, considered as the last option in the waste hierarchy. In this study, attempts were made to locate a new landfill in Oum Azza using the AHP multi-criteria decision-making method to assess the different criteria considered during the prospecting and combining them with the geographic information system to acquire the results in the form of maps displayed on the optimal sites to house a new controlled landfill and minimize its terrible impact on the environment

Contribution of geophysics for the characterization of ore deposits, case of the Bouarfa mine, Morocco.

Geophysical methods are one of the best ways to determine the potential of a mining area. Indeed, for the prospection of metalliferous deposits, the magnetic method remains essential as it makes it possible to characterize the extent and the depth of the anomalous bodies present in the prospected zone, mainly due to their reaction with the values of the total magnetic field. Thus, for the manganese mining zone of Bouarfa and more exactly Hammraouet, the genesis of the deposit is such that the manganese is generally associated with ferruginous minerals and clearly affect the total magnetic field. That said, the raw results obtained must imperatively be subjected to corrections to only keep the effect of the anomalous bodies on the magnetic field. Hence, we must proceed with the correction of the daytime effect then we eliminate the regional effects to get the map of the residual anomaly and finally we perform a reduction to the pole that will allow us to have well individualized and unipolar anomalies and thus allowing us to locate precisely the potentially mineralized axes. The synthesis of the various maps obtained by spatial interpolation of the data recorded in situ and corrected allows us to locate areas of mining interest and to determine the different tectonic phenomena that took place in our study area. In time, these maps will serve us to guide the subsequent mechanical surveys to confirm the results obtained by geophysical methods

Contribution of geophysics for the characterization of ore deposits, case of the Bouarfa mine, Morocco.

Geophysical methods are one of the best ways to determine the potential of a mining area. Indeed, for the prospection of metalliferous deposits, the magnetic method remains essential as it makes it possible to characterize the extent and the depth of the anomalous bodies present in the prospected zone, mainly due to their reaction with the values of the total magnetic field. Thus, for the manganese mining zone of Bouarfa and more exactly Hammraouet, the genesis of the deposit is such that the manganese is generally associated with ferruginous minerals and clearly affect the total magnetic field. That said, the raw results obtained must imperatively be subjected to corrections to only keep the effect of the anomalous bodies on the magnetic field. Hence, we must proceed with the correction of the daytime effect then we eliminate the regional effects to get the map of the residual anomaly and finally we perform a reduction to the pole that will allow us to have well individualized and unipolar anomalies and thus allowing us to locate precisely the potentially mineralized axes. The synthesis of the various maps obtained by spatial interpolation of the data recorded in situ and corrected allows us to locate areas of mining interest and to determine the different tectonic phenomena that took place in our study area. In time, these maps will serve us to guide the subsequent mechanical surveys to confirm the results obtained by geophysical methods

Characterization of Mineral Meposits Using the Magnetic Method: The Case of the Aïn Beida Mine in Bouarfa, Morocco

Geophysical methodologies represent a paramount approach for assessing the mining potential of a given area. Among these methodologies, the magnetic method stands out as indispensable for the exploration of metalliferous deposits. This method facilitates the characterization of both the lateral extent and vertical depth of anomalous bodies within the surveyed region, as discerned from their influence on the total magnetic field. In the case of the manganese-rich mining zone situated in Bouarfa, particularly in Aïn Beida, the mineral deposit genesis typically involves the association of manganese with ferruginous minerals, significantly perturbing the total magnetic field. However, the initial findings necessitate meticulous corrections to isolate the exclusive impact of anomalous bodies on the magnetic field. Accordingly, correction procedures must address diurnal variations prior to executing a Reduction to the Pole (RTP), enabling the identification of well-defined and unipolar anomalies crucial for precise delineation of potentially mineralized zones. Integration of spatially interpolated data yields comprehensive maps delineating areas of mining significance and elucidating pertinent geological phenomena within the study area. Subsequently, employing 2D modeling techniques on magnetic survey results facilitates accurate estimation of mineralized horizon extents and thicknesses. Ultimately, these synthesized maps serve as valuable guides for subsequent mechanical prospecting endeavors aimed at corroborating findings derived from geophysical methodologies

Spatio-Temporal Analysis of the Remote Sensing Ecological Index – A Case Study of the Favorable Agro-Ecological Zone in Northwest Morocco

Agriculture has traditionally been one of Morocco's most important industries, providing the largest percentage of the nation's GDP (Gross Domestic Product). However, over the past two decades, the frequency and severity of Morocco's droughts have grown. These climate changes have a direct impact on essential crops in the country. Exploring the geographical and temporal evolution of the ecological quality is thus critical for the conservation of the natural environment. To achieve this, the present study attempted to evaluate seasonally the environmental quality in the most favorable agro-ecologic zone in Morocco, using remote sensing data, in the years 2001, 2011, and 2021. An index was created, called Remote Sensing Environmental Index (RSEI), which combines four ecological indicators, related to vegetation, humidity, heat, and dryness aspects. The results indicate that from 2011 to 2021, the RSEI values deteriorated the greatest, particularly during the winter months. In addition, vegetation and humidity were the parameters most affecting the RSEI index. Thus, the key drivers of the improvement in the environmental quality are the establishment of ecological policies, rules, and actions to maintain a sustainable environmental development

Predictive modelling on Spatial–temporal Land Use and Land Cover changes at the Casablanca-Settat Region in Morocco

International audienceUrban Population growth coupled with human activities are the main drivers inducing land use and land cover changes (LU/LCC), which impact earth’s landscapes dynamics. In the era of global challenges, a comprehensive modelling of past and future prediction of LU/LCC is therefore essential. In this regard, the current study aims to model LU/LCC and predict its changes by 2030, 2050 and 2100. Moreover, determine the main driver of these changes, and assess the impact of urbanization on natural ecosystems. For doing so, a three-decade times series (1992–2020) data have been used, including LU/LC, environmental, societal, and auxiliary data to conduct a statistical analysis and modelling using hybrid Multi-Layer-Perceptron Markov-Chain model (MLP-MC). The analyses results showed that urbanization has significantly increased between 1992 and 2020, mainly in the outskirts of the Casablanca metropolis, where economic dynamic, population growth, and territorial infrastructure takes place. This increase was at the expense of barren and agricultural land. Concerning the future projection, the MLP-MC model showed satisfactory results with an overall accuracy (OA) and Cohen’s Kappa greater than 0.98 Revealing that the model has batter reliability to predict LU/LC maps that are identical to observed ones. Consequently, the Future projection indicates that urban areas will persistently sprawl, especially in satellite cities of the economic capital which adversely affect biodiversity, local climate, water, and public health. These findings remain so promising that can guide decision-making and stakeholders to improve sustainable territorial and urban development