BEHAVIOUR OF SOIL NAILED SLOPE UNDER SURCHARGE LOADING

Abstract

This thesis presents a comprehensive study of soil nailing as an effective and versatile technique for slope stabilization. Soil nailing has proven to be a reliable solution in civil engineering for reinforcing slopes, retaining walls, and stabilizing natural and man-made earth/soil structures. The research establishes a strong foundation by outlining the development, significance, and objectives of soil nailing. It provides an in-depth overview of suitable ground conditions, applications, and construction methods, along with a robust methodological framework incorporating slope stability analysis methods, earth pressure theories, cohesive backfill principles, and failure mode analyses. A detailed review of relevant literature synthesizes findings from physical modelling, numerical simulations, and different investigations on soil nail behaviour. The study investigates soil slope stability performance through experimental and numerical approaches. The experimental program includes soil testing procedures conducted using a Computerized Universal Testing Machine (UTM) for precise soil slope characterization. Materials and their physical and mechanical properties are thoroughly examined, along with laboratory testing procedures, experimental setups, and slope preparation techniques. Numerical modelling is also introduced, employing 2D FEM for slope stability analysis under surcharge loading and 3D FEM for bearing plate analysis. This integrated approach ensures a comprehensive understanding of the materials, methods, and software utilized. A meticulous investigation evaluates the effect of nail inclinations on slope stability using numerical simulations and experimental analyses, unveiling optimal nail inclination angles for enhancing stability and mitigating slope failure risks. Further v analysis explores the stability and behaviour of soil-nailed slopes, including the effects of tensile forces on soil nails, bearing plate behaviour under stressed conditions, and the pullout function of grouted nails. Flexural failure at the slope-facing is examined, highlighting critical failure mechanisms. Experimental investigations compare the performance of soil-nailed walls with grouted and non-grouted nails, offering valuable insights into their effectiveness. The research findings emphasize the superior effectiveness of soil nailing in slope stabilization. Validation through rigorous finite element model simulations strengthens the credibility of the conclusions. The study highlights the importance of optimal nail inclinations and grouted nails in mitigating slope instability and enhancing overall stability. The potential future scope and social impact of soil nailing in geotechnical engineering are also discussed, particularly in areas prone to landslides or hilly terrains. These insights contribute to robust and sustainable geotechnical solutions, emphasizing the need for continued research and innovation in this field. In summary, this thesis provides significant insights into the technical importance of soil nailing, offering practical recommendations for its widespread application in Civil Engineering projects. The research enhances understanding through experimental investigations and advanced numerical analyses, underscoring soil nailing's pivotal role in modern geotechnical engineering practices.