http://archives.univ-biskra.dz/handle/123456789/179 Mon, 06 Apr 2026 03:57:17 GMT 2026-04-06T03:57:17Z http://archives.univ-biskra.dz/handle/123456789/31526 Titre: Classification Of Irrigation Water Based On Machine Learning Approach Auteur(s): Aymen ZEGAAR Résumé: This thesis pioneers the integration of advanced machine learning models into irrigation water classification. Starting from groundwater quality assessment through IWQI, and groundwater classification, the research evolves to leverage ML model interpretability for predictions. It marks a paradigm shift in water quality assessment methodologies, emphasizing potential efficiency gains. The application of machine learning assures accurate simulation of the Irrigation Water Quality Index (IWQI) and streamlined economic monitoring approach. This work carries substantial implications for water resource management, particularly benefiting farmers and decision-makers. The findings contribute to the advancement of sustainable water management practices, providing a transformative perspective at the intersection of machine learning and irrigation water quality assessment. Description: Water resources Wed, 01 Jan 2025 00:00:00 GMT http://archives.univ-biskra.dz/handle/123456789/31526 2025-01-01T00:00:00Z http://archives.univ-biskra.dz/handle/123456789/31525 Titre: Contribution à l'étude du comportement mécanique des structures courbées en matériaux avancés Auteur(s): Soufiane BENOUNAS Résumé: Doubly curved shallow shells (DCSSs), frequently encountered in advanced engineering such as aerospace, civil, and mechanical engineering, present substantial challenges in predicting mechanical responses due to their complex geometry and material properties. Moreover, research on functionally graded doubly curved shallow shells (FG DCSs) is very limited, with most studies relying on analytical methods, highlighting the need for a novel and efficient approach to improve predictive analysis. Therefore, to address this gap, the aim of this research work is to develop an efficient and simple finite element model to investigate the bending deflection, stress distribution, and free vibration behavior of FG DCSSs. A new eight-node quadrilateral isoparametric element, named SQ8-IFSDT, with five degrees of freedom per node, is formulated based on improved first order shear deformation theory (IFSDT). The present IFSDT simplifies the assumptions related to transverse shear stresses, replacing the conventional shear correction factor. As a result, it accurately predicts the parabolic shear stress distribution across the thickness of the shell while maintaining free traction conditions on both surfaces. In the present study, five types of DCSSs, namely flat plates, cylindrical shells, spherical shells, hyperbolic paraboloid shells, and elliptical paraboloid shells, are considered for the analysis. The material properties of FG DCSS change continuously across the thickness according to a power-law function. A variety of comparative studies is conducted to assess the accuracy and robustness of the developed finite element model. A comparison study shows that the proposed model is: (a) accurate and comparable with the literature; b) of fast rate of convergence to the reference solution; c) excellent in terms of numerical stability; and d) valid for both thin and thick FG DCSs. Moreover, comprehensive numerical results are presented and discussed in detail to examine the effects of material properties, power-law index, radius-to-thickness ratio, radius-to-side ratio, radii of curvature, loading, vibration modes, and boundary conditions on the bending and free vibration response of FG DCSSs. Finally, the outcomes of this research provide a robust benchmark for the design, testing, and manufacture of DCSSs and will inform future investigations into shell structures. Description: Voies et Ouvrages d’art Wed, 01 Jan 2025 00:00:00 GMT http://archives.univ-biskra.dz/handle/123456789/31525 2025-01-01T00:00:00Z http://archives.univ-biskra.dz/handle/123456789/31524 Titre: The Effect of Mineral Additions on the Curing Process, Rheology and Durability of Heat Treated High Performance Concrete Auteur(s): Seifeddine Mehdi LAHMAR Résumé: The demand for sustainable, high-performance construction materials has driven research into alternative cementitious materials. This study explores the potential of locally sourced Algerian andesite and calcined marl as supplementary cementitious materials (SCMs) in high performance concrete (HPC). It examines their impact under heat-treated and non-heat-treated conditions, emphasizing pozzolanic reactivity and fresh and hardened state properties. Comprehensive characterization using X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) determined the chemical composition and microstructural attributes of these materials. The Sherbrooke mix design optimized HPC formulations. Partial cement replacement was carried out at levels of 10%, 20%, and 30% by mass, using andesite and calcined marl, with natural pozzolan serving as the reference mix. Experimental evaluations covered workability, ultrasonic pulse velocity (UPV), porosity, water absorption, and compressive strength. Advanced imaging techniques, particularly computed tomography, assessed internal microstructural evolution, while statistical modeling (Design of Experiments, DOE) provided deeper insights into performance optimization. Results confirm that andesite and calcined marl demonstrate good performance characteristics compared to the natural pozzolan reference. Fresh-state assessments showed favorable workability and stability, while hardened-state analyses revealed reduced porosity, denser microstructure, and satisfactory durability. Heat-treated samples exhibited notable early-age strength, benefiting precast and rapid construction. Non-heat-treated specimens, however, developed long-term durability through sustained pozzolanic activity. Sulfuric acid exposure confirmed the chemical resilience of these formulations, reinforcing their suitability for demanding environments. This research advances the valorization of local mineral resources for sustainable HPC, reducing reliance on imports. The combined benefits of thermal curing and pozzolanic synergy offer a durable, eco-friendly concrete solution. By bridging material characterization, performance optimization, and practical implementation, this study provides valuable insights for academia and industry, fostering resilient, resource-efficient construction methodologies. Description: CONSTRUCTION MATERIALS Wed, 01 Jan 2025 00:00:00 GMT http://archives.univ-biskra.dz/handle/123456789/31524 2025-01-01T00:00:00Z http://archives.univ-biskra.dz/handle/123456789/31523 Titre: Etude de la pathologie des fissurations de bâtiment suite au phénomène de dissolution du gypse cas des bâtiments de Ouled Djellal. Auteur(s): REBIAI Farouk Résumé: This thesis investigates the pathology of building cracks caused by ground movement resulting from gypsum dissolution in Ouled Djellal. The research begins with a comprehensive literature review addressing gypsum soils, the dissolution process, associated geohazards, structural risks, assessment methodologies, and engineering solutions within a broader risk management framework. A pre-diagnosis phase was conducted on 55 buildings, revealing significant damage affecting structural and non-structural elements. Issues included tilting, cracking, swelling, detachment of exterior cladding, and functional impairments such as door and window sticking. Environmental analysis led to the hypothesis that these issues stem from ground movement triggered by the dissolution of gypsum, primarily initiated by water infiltration due to leakage.A detailed diagnostic phase followed, focusing on 11 buildings to confirm the failure mechanisms hypothesized earlier. The findings revealed the presence of gypsiferous soils, which considerably degrade mechanical behavior when exposed to moisture. This hydro-collapse phenomenon is driven by the dissolution and transport of soil particles within the Pliocene layer (3 to 7 meters deep), where the building foundations are anchored. The affected soil comprises sandy clay, sandstone, and a conglomerate matrix, characterized by pores, cavities, and cracks that contribute to instability. Additionally, inadequate foundation designs—featuring isolated and combined footings—have exacerbated the damage. Differential settlement, caused by the heterogeneity of the soil’s depth and composition, was identified as the primary failure mechanism, resulting in stress concentrations and material degradation. Based on these findings, a comprehensive risk management strategy is proposed. Preventive measures include improved water management, piezometric monitoring, and ongoing observation of subsurface warning signs. Remedial techniques discussed include grouting using the GIN method and the enlargement of isolated footings to form cross-strip footings. The recommendations also integrate urban planning strategies for both local (Ouled Djellal) and national implementation. Description: MATERIAUX DE CONSTRUCTION Wed, 01 Jan 2025 00:00:00 GMT http://archives.univ-biskra.dz/handle/123456789/31523 2025-01-01T00:00:00Z