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Enhancing performance of soil using lime and precluding landslide in Benin(West Africa)

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Journal of Central South University 2019年第11期26卷 3066-3086页

作者： Quirin Engelbert Ayeditan ALAYE LING Xian-zhang Yvette Sèdjro KIKI TANKPINOU marx ferdinand ahlinhan LUO Jun Michel Hadilou ALAYE School of Civil Engineering Harbin Institute of TechnologyHarbin 150001China National University of Sciences TechnologiesEngineering and Mathematics(UNSTIM)Abomey 133Benin(West Africa Ministry of Public Works and Transport 01 BP 351 CotonouBenin(West Africa

The past decade has been characterized by the development of infrastructure in the main cities in West *** requires more comprehensive studies of geotechnical properties of the soil in the region with an aim of creating sustainable *** paper examined the performance of the soil in Benin(West Africa).In this research,three objectives have been adopted in-depth on the performance characteristics of West Africans soil and aim to(i)accessing characteristics of soil types in the region;(ii)assessing the performance of these soils with 2%,3%and 5%of lime and(iii)characterizing landslide to evaluate the damage and potential *** methods used to examine these objectives are experimental tests according to standard French *** particle size test,Proctor test,and Atterberg limits test which are physical tests and the mechanical tests such as dynamic penetration test,direct shear test,and oedometer test,were used to assess the first *** Proctor test and California bearing ratio test were examined for the second objective and geological,environmental,social and safety study of the river bank slide were evaluated for the third *** paper firstly reveals the unstable and stable areas in southern Benin(West Africa)with the presence of clays soil and gives an equation for predicting the unstable and stable area,and secondly shows that the proportion of percentage lime leading to the best performances varying between 2%and 3%.Finally,this paper shows that the sliding of a bank could be the consequence of the sudden receding water recorded in a valley.

关键词： soil characterization soil performance clay soil lime landslide

Experimental and Numerical Investigation of Stress Condition in Unstable Soil

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Open Journal of Civil Engineering 2016年第3期6卷 370-380页

作者： marx ferdinand ahlinhan Emmanuel Kokou Wouya Yvette Kiki Tankpinou Marius Bocco Koube Codjo Edmond Adjovi School of Sciences and Technologies for Building and Road (ESTBR) Polytechnic University of Abomey (UPA) Abomey Benin Institute University of Technology Lokossa (IUT) University of Lokossa Lokossa Benin

In unstable soils, a special erosion process termed suffusion can occur under the effect of relatively low hydraulic gradient. The critical hydraulic gradient of an unstable soil is smaller than in stable soils, which is described by a reduction factor α. According to a theory of Skempton and Brogan (1994) [1], this reduction factor is related to the stress conditions in the soil. In an unstable soil, the average stresses acting in the fine portion are believed to be smaller than the average stresses in the coarse portion. It is assumed that the stress ratio and the reduction factor for the hydraulic gradient are almost equal. In order to prove this theory, laboratory tests and discrete element modelings are carried out. Models of stable and unstable soils are established, and the stresses inside the sample are analysed. It is found that indeed in unstable soils the coarse grains are subject to larger stresses. The stress ratios in stable soils are almost unity, whereas in unstable soils smaller stress ratios, which are dependent on the soil composition and on the relative density of the soil, are obtained. A comparison between the results of erosion tests and numerical modeling shows that the stress ratios and the reduction factors are strongly related, as assumed by Skempton and Brogan (1994) [1].

关键词： Unstable Soil Suffusion Hydraulic Gradient Stress Reduction Factor Laboratory Tests Discrete Element Modeling

Experiments and 3D DEM of Triaxial Compression Tests under Special Consideration of Particle Stiffness

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Geomaterials 2018年第4期8卷 39-62页

作者： marx ferdinand ahlinhan Ernesto Houehanou Marius Bocco Koube Valery Doko Quirin Alaye Nicholas Sungura Edmond Adjovi National University of Sciences Technologies Engineering and Mathematics (UNSTIM) Abomey Republic of Benin University of Abomey Calavi Abomey Calavi Republic of Benin Harbin institute of Technology Harbin China Deutsche Bahn Hannover Germany

Discrete element modelling is commonly used for particle-scale modelling of granular or particulate materials. Developing a DEM model requires the determination of a number of micro-structural parameters, including the particle contact stiffness and the particle-particle friction. These parameters cannot easily be measured in the laboratory or directly related to measurable, physical material parameters. Therefore, a calibration process is typically used to determine the values for use in simulations of physical systems. This paper focuses on how to define the particle stiffness for the discrete element modelling in order to perform realistic simulations of granular materials in the case of linear contact model. For that, laboratory tests and numerical discrete element modelling of triaxial compression tests have been carried out on two different non-cohesive soils i.e. poorly graded fine sand and gap graded coarse sand. The results of experimental tests are used to calibrate the numerical model. It is found that the numerical results are qualitatively and quantitatively in good agreement with the laboratory tests results. Moreover, the results show that the stress dependent of soil behaviour can be reproduced well by assigning the particle stiffness as a function of the particle size particularly for gap graded soil.

关键词： Grain Size Dependent Stiffness Experiment Discrete Element Modelling Triaxial Compression Test Non-Cohesive Soils Materials

Experimental Analysis of Hydraulic Conductivity for Saturated Granular Soils

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Geomaterials 2023年第3期13卷 71-90页

作者： ahlinhan marx ferdinand Djenou B. Dorothée Adjovi Edmond Codjo Laboratory of Study and Test in Civil Engineering (L2EGC) National High School of Public Works (ENSTP) National University of Sciences Technologies Engineering and Mathematics (UNSTIM) Abomey Republic of Benin

Hydraulic conductivity is the ability of a porous media to transfer water through its pore matrix. That is a key parameter for the design and analysis of soil fluid associated structures and issues. This paper presents the test results of the vertical hydraulic conductivity kv carried out on one poorly graded sand and three gap graded gravely sand. It was found that the vertical hydraulic conductivity of saturated soil depends on the grain size distribution curve, on the initial relative density of the soil. Compilation of these current test results and other test results published, shows that the common approaches predict well to some extent the vertical hydraulic conductivity kv for the poorly graded sand materials and underestimate the kv values for gap graded gravely sand materials. Therefore, new approaches are developed for the prediction of the vertical hydraulic conductivity in saturated poorly graded sand and gap graded gravely sand. The derived results from the new approaches lie in the range of the recommended values by (EAU 2012) and (NAVFAC DM 7 1974).

关键词： Permeability Hydraulic Conductivity Tests Saturated Granular Soils Prediction Approaches