Géotechnical Modeling Of Slope Stability : case study and risk assement “open trench excavation in BEKKARIA”

Abstract

Abstract This study investigates slope stability challenges in a geologically complex mountainous terrain where a phosphate transport railway is being constructed. Combining advanced numerical modeling (PLAXIS 2D/2024) with comprehensive field investigations, the research evaluates stability across three distinct geological facies: unstable diapiric gypsum-clay formations requiring reinforcement, competent limestone strata demonstrating inherent stability, and plastic clays showing critical susceptibility to failure. Key findings reveal rainfall infiltration reduces safety factors by 25-40% in weak formations, while dynamic train loads induce progressive deformations (<5 mm) in plastic clays. The study establishes optimal slope designs (65° benched excavations) and proposes targeted mitigation measures including drainage systems and soil nailing. By developing a validated modeling framework for multilithological terrains, this research provides both practical solutions for the current project and a methodological template for similar infrastructure developments in geologically challenging environments. The results emphasize the necessity of lithology-specific engineering approaches and real-time monitoring to ensure long-term slope stability Keywords: Slope stability analysis; Geotechnical modeling; Diapiric formations; PLAXIS 2D simulation; Rainfall-induced landslides; Mining infrastructure.