Comparing the Flow Properties of Bulk Solids by Tri-axial Shear, Unconfined Yield and Direct Shear Tests [Translated]†

Abstract

This paper discusses a comparison of the data of experiments obtained by using different shear tests methods in order to examine the confidence in the results of experiments on the flow properties of a bulk solid. The angle of internal friction of dry granular materials, which has been measured by both a tri-axial shear tester and a fixed volume direct shear tester, increases with a decrease in the voidage of the specimen. Except for the extremely dense and loosely packed states, the experimental results of the angle of internal friction agree within about 3 degrees. There is however a difference of 3 to 5 degrees for a material in which the particle shape is deflective. The flowability index of cohesive powders and wet materials is expressed by a ratio of the unconfined yield strength to the bulk density. The results of experiments on the flowability index are independent of the unconfined yield and direct shear tests.† This report was originally printed in J. Soc. Powder Technology, Japan, 23(9), 678-684 (1986) in Japanese, before being translated into English by KONA Editorial Committee with the permission of the editorial committee of the Soc. Powder Technology, Japan.