Static Stress Conditions of a Cohesive Powder in Bins [Translated]†

Abstract

The following results were experimentally obtained by analyzing the packing and stress conditions of CaCO3 (P-30) powder filled through a sieve into a shallow and a deep bin of low and high powder-bed height to bin diameter ratio, respectively: 1) The ratio of horizontal stress to vertical stress in the powder at the bin wall increased linearly with decreasing porosity in both cases. 2) The relationship between the logarithm of mean consolidation stress and the void ratio was linear in both cases. 3) In the shallow bin the vertical stresses in the radial direction were observed to be almost uniform. Hence the stress condition in the powder was well expressed by Janssen's equation, evaluated using the coefficient of wall friction measured by a direct shear tester. 4) The Mohr circles which represented the stress conditions of the powder at the bin wall were not tangent to the effective yield locus, but approximately tangent to the wall yield locus. 5) The static state of the powder in the deep bin could be roughly estimated by using the results obtained in the shallow bin.† This report was originally printed in KAGAKU KOGAKU RONBUNSHU, 10(6), 667-674 (1984) in Japanese, before being translated into English by KONA Editorial Committee with the permission of the editorial committee of the Soc. Chemical Engineers, Japan.