Numerical Modeling of Soil Erosion with Three Wall Laws at the Soil-Water Interface

In the area of civil engineering and especially hydraulic structures, we find multiple anomalies that weakens mechanical characteristics of dikes, one of the most common anomalies is erosion phenomenon specifically pipe flow erosion which causes major damage to dam structures. This phenomenon is caused by a hole which is the result of the high pressure of water that facilitate the soil migration between the two sides of the dam. It becomes only a question of time until the diameter of the hole expands and causes destruction of the dam structure. This problem pushed physicist to perform many tests to quantify erosion kinetics, one of the most used tests to have logical and trusted results is the HET (hole erosion test). Meanwhile there is not much research regarding the models that govern these types of tests. Objectives: In this paper we modeled the HET using modeling software based on the Navier Stokes equations, this model tackles also the singularity of the interface structure/water using wall laws for a flow turbulence. Methods/Analysis: The studied soil in this paper is a clay soil, clay soil has the property of containing water more than most other soils. Three wall laws were applied on the soil / water interface to calculate the erosion rate in order to avoid the rupture of such a structure. The modlisitation was made on the ANSYS software. Findings: In this work, two-dimensional modeling was carried of the soil.in contrast of the early models which is one-dimensional model, the first one had shown that the wall-shear stress which is not uniform along the whole wall. Then using the linear erosion law to predict the non-uniform erosion along the whole length. The previous study found that the wall laws have a significant impact on the wall-shear stress, which affects the erosion interface in the fluid/soil, particularly at the hole's extremes. Our experiment revealed that the degraded profile is not uniform. Doi: 10.28991/cej-2021-03091742 Full Text: PD

The return to higher education by gender: Case of Morocco: Le rendement de l’enseignement supérieur par genre : Cas du Maroc

Résumé La majorité des études et des analyses menées en termes discrimination de genre sur le marché du travail aboutissent que les hommes et les femmes ne sont constamment pas domiciliées à la même enseigne. La présente étude s’est interrogée sur l’écart salarial entre les hommes et les femmes au Maroc, mais cette fois exclusivement au niveau des diplômés de l’enseignement supérieur à savoir comment leurs aptitudes sont appréciées sur le marché d’emploi. Dont l’objectif principal est de savoir s’il existe des effets discriminatoires au niveau des compétences élevées. À partir d’une base récente de données provienne de l’enquête nationale d’emploi en 2018. Il a été conclu que l’écart de salaire entre les hommes et les femmes diplômées au Maroc s’était réduit dans le public, mais considérablement dans le privé. Nous avons utilisé la méthode de décomposition d’Oaxaca et Blinder. L’estimation a révélée que les femmes diplômées sont rémunérées de 19.45 % moins que les hommes diplômés de 36.95 % inexpliqué. Ce taux traduit ainsi la discrimination à l’égard des femmes même s’elles disposent un stock de capital humain élevé. Par ailleurs, les différences des caractéristiques expliquent quant à elles, la présence de -17,50 % indiquant ainsi que l’écart opère en faveur des femmes. Nous conclusion que les femmes diplômées subissent une sous-estimation de leurs compétences sur le marché d’emploi. Mots clés : L’écart salarial, La méthode de décomposition d’Oaxaca et Blinder, Le marché d’emploi   Abstract The majority of studies and analyzes carried out in terms of gender discrimination in the labor market find that men and women are not always domiciled in the same vein. The present study questioned the pay gap between men and women in Morocco, but this time exclusively at the level of higher education graduates, to know how their skills are appreciated in the labor market. The main objective of which is to find out whether there are discriminatory effects at the level of high skills. From a recent database comes from the national employment survey in 2018. It was concluded that the pay gap between men and women graduates in Morocco had narrowed in the public, but considerably in the private sector. We used the Oaxaca and Blinder decomposition method. The estimate revealed that female graduates are paid 19.45% less than male graduates an unexplained 36.95%. This rate thus reflects discrimination against women even if they have a high stock of human capital. In addition, the differences in characteristics explain, for their part, the presence of -17.50% indicating that the gap operates in favor of women. We conclude that female graduates experience an underestimation of their skills in the labor market. Keywords : The pay gap, The Oaxaca and Blinder decomposition method, The job marke

Prediction of Internal Soil Erosion in Hydraulic Works

Hydraulic structures built on land, such as dams, are numerous and essential as their purpose is to protect people and property (dikes and levees), generate electricity, or create water reserves (dams). Soil erosion, known as hydraulic foxing, is a complex phenomenon which, in its ultimate stage, produces insidious leakage of fluids beneath hydraulic infrastructures known as pipes, and is the main cause of their failure. The HET pipe erosion test is commonly used to quantify the rate of pipe erosion. In this work, the hole erosion test is modeled using ANSYS Fluent software. The aim is to predict the soil erosion rate during the hole erosion test in order to predict the phenomenon of hydraulic foxing within hydraulic structures. The renormalization group theory-based k−ε turbulence model equations are used. This modeling makes it possible to describe the effect of the clay concentration in flowing water on erosion. Contrary to the usual one-dimensional models, the modeling proposed in this study shows that erosion is not uniform along the entire length of the hole. In particular, clay concentration was found to significantly increase the erosion rate