A theoretical analysis of stresses in silos with vertical walls

Abstract The approximate theory of Walker [1] is extended to distinguish between the stresses developed during the initial filling of the silo (“static” conditions) and those developed during flow (“dynamic” conditions). As flow develops, the transition between dynamic and static conditions moves upwards and a large lateral stress exists at the transition. This “switch” stress of Jenike and Johanson[2] is estimated from the approximate theory and is in good agreement with their values. It is suggested that the present simple analysis is suitable for estimating wall stresses for use in structural design. Data are given in graphical form in terms of the effective angle of internal friction of the bulk solids δ and the angle of wall friction φ.