Effects of friction and cohesion on the pressure dip of granular pile

The anomalous pressure dip beneath granular piles presents an enduring challenge in granular mechanics, arising from a complex interplay of deposition history and particle properties. This study systematically investigates the roles of basal friction, interparticle cohesion (quantified by the granular Bond number), and particle shape on this phenomenon. Combining load-cell experiments with Discrete Element Method simulations for both spherical and non-spherical clinoptilolite particles, we demonstrate that the pressure dip diminishes and ultimately vanishes as basal roughness increases. This trend is markedly more pronounced for non-spherical particles. Furthermore, while interparticle cohesion significantly increases the angle of repose, it systematically reduces the magnitude of the pressure dip, an effect quantified by a Center Relative Pressure Deviation Ratio. Our findings suggest that the pressure dip emerges under a critical balance between particle rearrangement and stress transmission, underscoring the decisive roles of boundary constraints and bulk flowability. • •Pressure profile beneath granular piles is measured using load cells and DEM simulations. • •Increasing basal roughness progressively weakens and eventually eliminates the central pressure dip. • •Interparticle cohesion suppresses the pressure dip by altering force transmission within granular piles.