At the International Conference on the Design of Silos for Strength and Flow held at the University of Lancaster, England, in September 1980, these authors emphasized the relevance and importance of accurate knowledge of the structural anisotropy of powdered solid materials, whether cohesive or non-cohesive and the accurate determination of various physical and mechanical parameters. At another conference [6] these authors also indicated that there are several important ratios and functional relationships between the parameters β, ϕ, ϕ0, and the principal stresses σ1 and σ3 appertaining to the properties of powdered materials which can be determined using triaxial tests. Concerning the study of structural anisotropy of a pulverulent medium, these authors were able to demonstrate clearly the functional relationship between the apparent cohesion and the minimum cohesion [7]...
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