Probabilistic stability analyses of active shallow trapdoor in spatially random sand

Understanding the influence of spatial variability in soil friction angle on trapdoor stability remains crucial, particularly in commonly encountered shallow active trapdoor configurations within sandy deposits. This study presents a probabilistic stability assessment of shallow active trapdoors in spatially random sands, employing Random Adaptive Finite Element Limit Analysis (RAFELA) integrated with Monte Carlo simulations (MCs). The numerical solutions, expressed in terms of stability number, are validated through both deterministic and probabilistic analyses. A comprehensive parametric study examines the effects of cover depth, soil friction angle, and spatial variability parameters (including coefficient of variation and horizontal/vertical correlation lengths) on the probability of failure (PF) corresponding to selected factors of safety (FoS). The observed failure mechanisms reveal distinctively variable sliding surfaces, highlighting the nature of random field problems in geomechanics. The study culminates in the development of practical contour-based design charts for a quick assessment of PF in active shallow trapdoors embedded in spatially random sands. These research outcomes offer valuable guidance for engineers, facilitating informed decision-making during preliminary design of buried structures.