A Discrete Packing Model of Granular Material Confined in A Vertical Column

TL;DR

This paper presents a discrete packing model for granular materials in a vertical column, analyzing force transmission, pressure saturation, and effects of friction and particle size, validated by experimental comparisons.

Contribution

It introduces a novel discrete packing model that predicts static pressure and saturation behavior considering frictional contacts and particle properties.

Findings

Silo effect caused by frictional contact with walls.

Static pressure tends to an exponential saturation value.

Saturation pressure is linearly related to container radius and particle size.

Abstract

The transmission rules of interparticle forces between granular particles were analyzed, and a discrete packing model was proposed to calculate the static pressure at the bottom of granular material confined in a vertical column. The mechanical analysis and numerical simulation results indicate that the silo effect is caused by the frictional contacts between border particles and inner walls, the static pressure at the bottom depends on the external load initially, and then tends to a saturation pressure (Pn) in an exponential form. The saturation pressure (Pn) is positive linear related to the container radius (R) with the same granular matter and stacking manner. The saturation pressure (Pn) is directly proportional to the particle size (ra), and the increasing or decreasing characteristic depends on the frictional property of inner walls, the friction and stacking angle of grains. At last, the predictions of the aforementioned model are compared with the experimental results from the literature, and good agreement is achieved.