ABSTRACT
Two main scales can be considered for analysing the mechanical behaviour of bulk solids in relation to silo flow and wall pressure problems as illus trated in Table 34.1. At a microscopic scale, the material is a discontinuous set of a finite and often small number of individual particles. At this scale, the analysis focuses on the understanding of fundamental phenomena in volved in bulk solids behaviour and on their consequences on silo flow and wall pressures. In this case the solutions, exclusively numerical, use discrete particle models among which the distinct element method is the most frequent. At a macroscopic scale, the material sample is considered to be continuous and homogeneous. This is the most traditional scale of analysis, as it is closer to the overall structure scale and more directly related to practical problems. The mathematical solutions at this scale can be analy tical such as Janssen’s methods or numerical such as the finite element method.
