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Characterization of Near Surface Intrusions in South-West Cameroon Zone Using Gravity Data: Mining and Geothermal Implications

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Journal of Geoscience and Environment Protection 2023年第9期11卷 268-296页

作者： Ghislain Nkamgan Ndongmo Fidèle Koumetio françois ngapgue Ernest Léontin Lemoubou Laboratory of Environmental Physics Faculty of Sciences University of Dschang Dschang Cameroon Research Unit of Mechanics and Physical Systems Modeling (UR-2MSP) Department of Physics Faculty of Sciences University of Dschang Dschang Cameroon

The succession of tectonic phenomena in the South-West Cameroon area suggests that structures from the upper mantle infiltrated and took advantage of the cracks and fractures left by these phenomena to get closer to the earth’s surface. However, the intrusive structures closest to the surface remain poorly known. The objective of this work is to improve the knowledge related to the interpretation of gravity data in order to characterise the near-surface intrusive bodies in the South-West Cameroon area, and then analyse their mining and geothermal implications. To achieve this objective, the indirect, inverse and normalized standard deviation (NSTD) methods were used. The NSTD method was used to detect the contours of the intrusive bodies. The indirect method (spectral analysis) was used to determine the depths of the interfaces of three intrusive bodies, one located on the Bipindi-Ebolowa I axis (G5), the other on the Eseka-Pouma axis (G8) and the last on the Bokito-Monatele axis (G11). The results obtained show roofs located between 0 and 0.61 km, between 0 and 0.37 km and between 0 and 0.73 km for the G5, G8 and G11 bodies, respectively. Finally, the application of the 2D inversion method allowed us to estimate the density contrasts of the intrusive bodies (G5, G8 and G11). The superposition of the intrusive bodies detected by the NSTD with the geological and mineral resources map, as well as an analysis of the results obtained, gave indications of interesting zones for mining prospecting and for the search for geothermal reservoirs.

关键词： Bouguer Anomaly Spectral Analysis Inverse Method NSTD Method Intrusive Body

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Contribution to the Characterization of Lateritic Soils for the Manufacture of Compressed Stabilized Earth Bricks

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Open Journal of Civil Engineering 2021年第4期11卷 411-426页

作者： Cherif Bishweka Marcelline Blanche Manjia françois ngapgue Ursula Joyce Merveilles Pettang Nana Chrispin Pettang Department of Civil Engineering Faculty of Sciences and Applied Technologies Free University of the Great Lakes Countries Congo North Kivu Goma Civil and Mechanical Engineering Laboratory Research and Postgraduate Training Unit for Engineering and Applications Science Post Graduate School for Science Technology and Geosciences University of Yaoundé I Yaoundé Cameroon Department of Civil Engineering National Advanced School of Engineering Yaoundé University of Yaoundé I Yaoundé Cameroon Fotso Victor University Institute of Technology Bandjoun University of Dschang Dschang Cameroon

The aim of this study is to contribute to the mastery of the physical characteristics of lateritic soils in order to improve their use for the manufacture of Compressed Stabilized Earth Bricks (CSEB) in the province of North Kivu in the Democratic Republic of Congo (DRC). The study of the physical characteristics of lateritic soils was carried out. Samples were subjected to experimental identification tests on the physical characteristics (water content, density characteristics, particle size distribution and consistency). The results of the laboratory analysis of soil samples show that the water content varies between 5.4% and 36.99%. The density of the solid grains has an arithmetic mean of 2.5 g/cm3. The apparent density varies from 0.83 to 1.35 g/cm3. As for the dry density, it is in the range of 0.61 to 1.25 g/cm3. These relatively low densities indicate that the material studied has a significant degree of deformability. From the particle size analysis, it appears that the material studied contains an important fraction of fine particles. According to the consistency study, the soils studied are plastic clay as Ap class according to the Central Laboratory for Roads and Bridges (CLRB) ge

关键词： Lateritic Soils Identification Tests Characterization Classification Earth Construction

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Mathematical Modeling of Shear Stress and Direct Shear Test for Compressible Soil: Case of Soil Bordering the Wouri River

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World Journal of Engineering and Technology 2021年第3期9卷 385-406页

作者： Michael Soup Teoua Ouagni françois ngapgue Fabien Kenmogne Alain Soup Tewa Kammogne Simon Ngoh Koumi Dschang School of Science and Technology (DSST) Department of Physics Mechanical Unit of Research and Modeling Physical Systems Energy-Mechanic University of Dschang Cameroon Dschang Cameroon Department of Civil Engineering Fotso Victor Institute of Technology University of Dschang Bandjoun Cameroon Department of Civil Engineering Higher Teacher Training College of Technical Education University of Douala Douala Cameroon Laboratory of Condensed Matter Electronics and Signal Processing (LAMACETS) Faculty of Sciences University of Dschang Dschang Cameroon Department Thermal Engineering and Energy Douala University Institute of Technology Douala Cameroon

This paper focuses on the development of the mathematical model of shear stress by direct shear test for compressible soil of the littoral region, which will be a great tool in the hand of geotechnical engineers. The most common use of a shear test is to determine the shear strength which is the maximum shear stress that a material can withstand before the failure occurs. This parameter is useful in many engineering designs such as foundations, roads and retaining walls. We carried out an experimental laboratory test of ten samples of undisturbed soil taken at different points of the border of Wouri river of Cameroon. The samples were collected at different depths and a direct shear test was conducted. The investigations have been performed under constant vertical stresses and constant sample volume with the aim to determine the frictional angle and the cohesion of the compressible soil which are so important to establish the conditions of buildings stability. Special care was taken to derive loading conditions actually existing in the ground and to duplicate them in the laboratory. Given that the buildings constructed in this area are subjected to settlement, landslide, and punch break or shear failure, the cohesion and the frictional angle are determined through the rupture line after assessed the mean values of the shear stress for the considered ten samples. The bearing capacity of the soil, which is the fundamental soil parameter, was calculated. From the laboratory experimental results, the least squared method was used to derive an approximated mathematical model of the shearing stress. Many optimizations methods were then considered to reach the best adjustment.

关键词： Direct Shear Test Normal and Critical Stresses Frictional Angle Bearing Capacity Mathematical Model

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Geotechnical Identification and Classification of Soils as Flexible Pavement Subgrade of the Section Fongo Tongo-Melong

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Journal of Geoscience and Environment Protection 2020年第11期8卷 183-200页

作者： françois ngapgue Willy Chance Guimezap Kenou Jules Hermann Keyangue Tchouata Vladimir Willianov Keubou Tatapzia Yannick Mbeuteu Mbakop Research Unit of Mechanics and Physical Systems Modeling (UR2MPS) Faculty of Sciences University of Dschang Dschang Cameroon Laboratory of Engineering Industrial Systems and Environment (LISIE) FOTSO Victor University Institute of Technology University of Dschang Dschang Cameroon Laboratory of Environmental Geology Faculty of Sciences University of Dschang Dschang Cameroon Innovation Research Center Entrepreneurship (PRIE) Institut Universitaire de la Cote Douala Cameroon School of Geology and Mining Engineering (SGME) University of Ngaoundere Ngaoundere Cameroon Geotechnique Batiment et Travaux Publics (GEO TP) Douala Cameroon

The present study is inscribed within the framework of the geotechnical characterization of the soils of the Santchou plain, their classification for employment as pavement subgrade, various identification tests were carried out on the samples. The results obtained showed that with a wide range of different grain sizes, the studied soils showed low content in clay grains and dominance of either sand grains or silt grains, this can be explaining how most of these soil are poorly graded. According to the USDA textural classification, the grain size distribution of these soils makes them to be classified as Silty Loam types to Sandy Loam types. Despite of their organic matter content which is less than 10%, according to their respective methylene blue values, the soils studied along the section should be mainly loamy soil of medium plasticity to clayed soil, therefore showing a sensibility of its behavior to variation of water content. That last one is confirmed by the consistency parameters of these soils which show intermediate plasticity to highly plastic. Also, the bearing capacity proposed by these soils at their respective optimum dry densities is relatively small, although most of these experimental CBR values of the studied soils are more important than the ones prescribed by the AASHTO Classification system for A5, A6, and A7 types, and the French Highway Earthworks Manual Classifications system (GTR) for the corresponding A2 and A3 types.

关键词： Soil Classification Liquid Limit Natural Water Content Plasticity Index Methylene Blue Value Optimum Moisture Content California Bearing Ratio

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Evaluation of the Effect of Lime Content on the California Bearing Ratio of Silty Soils: Case of Fombap District

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Open Journal of Geology 2020年第11期10卷 1059-1071页

作者： Willy Chance Guimezap Kenou françois ngapgue Jules Hermann Keyangue Tchouata Vladimir Willianov Keubou Tatapzia Walter Jovic Kenou Jogo Research Unit of Mechanics and Physical Systems Modeling (UR2MPS) Faculty of Sciences University of Dschang Dschang Cameroon Laboratory of Engineering Industrial Systems and Environment (LISIE) FOTSO Victor University Institute of Technology University of Dschang Dschang Cameroon Research Center for Innovation and Entrepreneurship (PRIE) Institut Universitaire de la Cote Douala Cameroon Laboratory of Environmental Geology Faculty of Sciences University of Dschang Dschang Cameroon School of Geology and Mining Engineering (SGME) University of Ngaoundéré Ngaoundéré Cameroon Faculty of Arts Humanities and Social Sciences (FALSH) University of Yaoundé 1 Yaoundé Cameroon

The present study is inscribed within the framework of the amelioration of the soils of the Santchou plain for employment as pavement subgrade. The bearing capacity proposed by these soils at their respective optimum dry densities is relatively small, although most of these experimental California Bearing Ratio (CBR) values of the studied soils are more important than the ones prescribed by the American Association of State Highway and Transportation Officials Classification system (AASHTO) for A5, A6, and A7 types. The stabilization of this soils with lime has been chosen to improve the bearing capacity and by association, their resilient modulus. The results of this study show that the increase of lime content is not proportional with the increase of the expected mechanical performances. In fact, the literature explains that when the lime content arrives at an optimum, the mechanical parameters no longer increase, but decrease significantly. After this optimum, the soil stabilization no longer shows advantages in the increase of geo-mechanical properties of soils.

关键词： Soil Classification Lime Content California Bearing Ratio Soil Stabilization Subgrade

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Study of Sands from Bamendou-West Cameroon: Valorization for Concrete Mix Design

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Journal of Geoscience and Environment Protection 2024年第5期12卷 345-354页

作者： Keubou Tatapzia Vladimir Willianov Guimezap Kenou Willy Chance Manefouet Bertile Ilalie Kamga Djoumen Tatiana ngapgue françois Faculty of Sciences University of Dschang Dschang Cameroon Institut universitaire de la Cô te Douala Cameroun Department of Civil Engineering FOTSO Victor University Institute of Technology University of Dschang Bandjoun Cameroon

Bamendou (West Cameroon), has a huge potential in natural resources, especially sands. However, the use of these materials in civil engineering works leads to the appearance of numerous pathologies which in some cases lead to the total ruin of the works. In order to overcome these infrastructural problems, the main objective of this study is set at the improvement of the service life of structures built in Cameroon using local materials formed under climatic, geological and geotechnical conditions similar to those of materials in Bamendou. Eight sand samples were taken from the most representative and exploited quarries. The identification and classification of the sand taken from the most representative quarries in the study area show that they are mainly clayey, with an average sand equivalent of 57.54. In terms of granulometry, the curves of several sand samples do not fall within the granular range of sands used in the formulation of concrete. The modulus of fineness obtained by particle size analysis varies from 2.91 to 3.92 with an average of 3.31.

关键词： Residual Sand Formulation of Concrete Sand Equivalent Fitness Modulus Particle Size Bamendou

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River Sand Characterization for Its Use in Concrete: A Revue

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Open Journal of Civil Engineering 2023年第2期13卷 353-366页

作者： Muhindo Wa Muhindo Abdias Manjia Marcelline Blanche Ursula Joyce Pettang Nana Henry Fonbeyin Abanda ngapgue françois Pettang Chrispin Laboratory Engineering Civil and Mechanics Doctoral Research Unit for Engineering and Applications University of Yaoundé I Yaoundé Cameroon Buildings and Publics Works Section Institute of Building and Public Works Butembo Democratic Republic of Congo Department of Civil Engineering National Advanced School of Engineering University of Yaoundé 1 Yaoundé Cameroon Faculty of Technology Design and Environment Oxford Brookes University Oxford UK Department of Civil Engineering Fotso Victor University Institute of Technology University of Dschang Bandjoun Cameroon

Despite the gradual professionalization of the construction sector as well as the abundance of sand mining sites offered by the North Kivu, Democratic Republic of Congo Region, ignorance of materials by local builders persists. This is the case of quarries extracting river sand used to make concrete and mortar. However, the dosages of the various constituents are most often chosen on the basis of experience without any prior characterization of this material. This paper presents a comprehensive review of the characterization of river sand for its use in concrete in DRC. The origin and global use of river sand in construction are presented in percentage terms to highlight the importance of river sand as a construction material. The physical properties of river sand, including particle size distribution, bulk density, absolute density, and cleanliness are discussed in detail. The paper examines the effect of variations in river sand properties on concrete behavior, including density and compressive strength. Overall, this paper emphasizes the need to properly characterize river sand before using it in construction to ensure durable, high-quality structures. This will avoid the problems that are observed in particular a bad behavior of the coating on the walls;cracks and crumbling of the beams, lintels, posts and even the ruin of the structures.

关键词： Characterization River Sand Concrete Construction Material Structure

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Recovery of Mining Wastes in Building Materials: A Review

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Open Journal of Civil Engineering 2021年第4期11卷 379-397页

作者： Alinabiwe Nyamuhanga Ally Manjia Marcelline Blanche Ursula Joyce Pettang Nana Masika Muhiwa Grâce ngapgue françois Chrispin Pettang Laboratory Engineering Civil and Mechanics Doctoral Research Unit for Engineering and Applications University of Yaoundé I Yaoundé Cameroon Department of Civil Engineering Faculty of Applied Sciences and Technologies Free University of Great Lakes Countries Goma DRC Department of Civil Engineering National Advanced School of Engineering of Yaoundé University of Yaoundé I Yaoundé Cameroon Department of Civil Engineering Fotso Victor University Institute of Technology University of Dschang Bandjoun Cameroon

The use of materials from waste in buildings compensates for the lack of natural resources, solves the problem of waste management and provides an alternative technique for protection of the environment. There are a large number of industrial wastes that are used for full or partial replacement of raw materials in some construction materials. This review assesses mining waste in concrete as a substitute for aggregates and cement;in fired bricks as a substitute for soil;and in road backfill as a substitute for soil. This paper reviews some mining tailings, mine waste rocks and some slags obtained in the exploitation and/or processing of some ores including iron, gold, lead, phosphate, copper, coal, etc. Different physical properties, mechanical properties, chemical properties, heavy metal content, mineralogic composition, geotechnical properties and environmental properties (leaching test) of the mine wastes were examined. The physical, mechanical and environmental properties of the materials obtained by substitution of raw materials by mine waste were examined and compared to reference materials. Mining waste in cementitious materials offers good compressive strengths, while the porosity of the concrete and/or mortar is a factor influencing its toxicity. As for the waste in fired bricks, fired at a temperature of 900°C or more, it offers convincing compressive and flexural strengths. The few research studies obtained on the use of mining waste in road embankments have shown that mining waste can be used as a sub-base layer and backfill as long as it is not toxic. In addition, several other mining wastes require special attention as substitutes for raw materials in construction materials, such as coltan, cobalt.

关键词： Mining Waste Tailings Waste Rock Slug Fired Brick Backfill Material Cement Materials

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Substitution of Aggregates in Concrete and Mortar with Coltan Mining Waste: Mechanical, Environmental, and Economic Impact Case Study

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Journal of Minerals and Materials Characterization and Engineering 2024年第2期12卷 139-163页

作者： Alinabiwe Nyamuhanga Ally Élodie Ruffine Zang Masika Muhiwa Grâce Manjia Marcelline Blanche Ursula Joyce Merveilles Pettang Nana ngapgue françois Bella Nabil Chrispin Pettang Laboratory Engineering Civil and Mechanics Doctoral Research Unit for Engineering and Applications University of Yaound&#233 I Yaound&#233 Cameroon Department of Civil Engineering Faculty of Applied Sciences and Technologies Free University of Great Lakes Countries (ULPGL) Goma DRC Department of Civil Engineering National Advanced School of Engineering of Yaoundé University of Yaoundé I Yaoundé Cameroon Department of Civil Engineering Fotso Victor University Institute of Technology University of Dschang Bandjoun Cameroon FIMAS Laboratory Faculty of Technologies Tahri Mohamed University Bechar Algeria

The mining process involves drilling and excavation, resulting in the production of waste rock and tailings. The waste materials are then removed and stored in designated areas. This study aims to evaluate the mechanical strength and the environmental and economic impact of using Coltan Mining Waste (CMW) as a substitute for aggregates in concrete and mortar production. To achieve this, the CMW needs to be characterised. The Dreux Gorisse method was primarily used to produce concrete with a strength of 20 MPa at 28 days. The mortars, on the other hand, were formulated according to the NF P 18-452 standard. The environmental impact of using CMW as substitutes for natural aggregates in the production of concrete and mortar was analysed using SimaPro software. The results showed that mortars and concrete made with CMW have comparable compressive strengths to the reference mortar and concrete;reduce the negative impact on ecosystem quality, human health, resources, and climate change. It has also been shown that the substitution of aggregates by CMW reduces the cost of concrete and mortar as a function of the distance from the aggregate footprint.

关键词： Aggregate Coltan Mining Waste Concrete Mortar Mechanical Strength Life Cycle Analysis

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Physical Characterization of Batie and Bandjoun-Djione Sands(West-Cameroon),Used in the Manufacture of Concrete:Improvement of Resistance to Compression

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Journal of Materials Science and Chemical Engineering 2020年第5期8卷 10-20页

作者： Jules H.Keyangue Tchouata Casimir Gouafo Grégoire Kamdjo francois ngapgue Armand S.L.Wouatong School of Geology and Mining Engineering University of NgaoundereNgaoundereCameroon Fotso Victor Institute of Technology University of DschangDschangCameroon Faculty of Sciences University of DschangDschangCameroon

The objective of this work, was to characterize the sands of the quarries of: Bandjoun-Djione, Djengou, Hiala and La’gou I, mainly from their mechanical strengths, the equivalent of sand and the finesse module. In order to study the compressive strength of concrete made from these sands, we determined their granularity, fineness modulus and density;the concrete was then formulated by the Dreux-Gorisse method. A total of 72 specimens were constructed with the objective of achieving an average compressive strength of 25 MPa at 28 days. But we have obtained a compressive strength at 28 days, varying from 13.14 MPa to 17.50 MPa. The correction of the modulus of fineness of these sands made it possible to improve the granularity and increase the compressive strength of these concretes by more than 70%. We have thus obtained the compression resistance of 25 MPa aimed for each of the corrected sands.

关键词： Sand Granulometry Concrete Mechanical Resistance Djengou Hiala La’gou I Bandjoun-Djione

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