Experimental study on base pressure distribution of accumulations of granular materials

Addressing the issue of pressure reduction in accumulations of granular materials, the impact of varying funnel heights, particle sizes and particle shapes on the distribution of base pressure is investigated utilizing the point deposition method. The results show that the phenomenon of base pressure reduction is intricately linked to the formation of internal stress arches and influenced by the factors such as the height of the funnel, granulometry of the particles, and morphological characteristics of the granules. With the increase of the accumulations, there is an enhancement in the stability of the stress arches, leading to a convergence towards a steady state of the stress depression ratio. The base pressure measured increases with the increase of the vertical distance from the funnel to the apex of the accumulations, resulting in a decrease of the stress depression. The stress depression ratio within the accumulations exhibits a trend of the initial increase followed by a decrease as the particle size escalates, with a notable occurrence of stress concentration in the accumulations comprised of particles ranging from 0.6 to 1.18 mm in diameter. With the increase in the mass of the accumulations, the stress depression ratio for the standard sand samples initially increases and then decreases, whereas for the loose coal particles, a consistent decline is observed.