Assessing the shear strength of sand-clay mixtures: A DEM analysis with realistic sand particle shapes.

AbstractThe discrete element model (DEM), enhanced with realistic sand particle shapes and flexible boundaries, was applied to triaxial compression tests of sand-clay mixtures (SCM) to study the impact of sand size, content, and shape on the shear behavior. The model was calibrated using uniaxial compression test data from two SCM types with distinct sand grain shapes. Findings indicate that SCM with irregular sand particles achieved higher peak strengths than those with spherical particles at equivalent sand content and size, due to greater inter-particle locking at sand-clay interfaces. Under low confining pressure, the peak strength of SCM diminished with increasing sand content, attributed to lessened cohesion. Conversely, under high confining pressure, SCM exhibited an initial peak strength decrease followed by an increase, associated with the frictional angle’s variation with sand content. Additionally, larger sand particle sizes led to a decrease in the internal friction angle and a cohesion increase, which boosted SCM’s peak strength under low pressures but led to a slight decrease under high pressures. An empirical model, informed by DEM insights, was crafted to estimate SCM’s strength parameters, offering a valuable tool for assessing the safety of SCM in engineering applications. [ABSTRACT FROM AUTHOR]