Contribution to a theory of internai friction.

Abstract

From the notion of mean stress in a granular soil, the concept of continuum equivalent to a zone of soil is defined. After this, the author considers the polyhedra circumscribing the grains whose faces are defined by the contacts between grains. On basis of these polyhedra statically equivalent to the grains, an analysis is made of the corresponding equilibrium conditions. This analysis becomes easier as it is proved that the forces acting in the polyhedra network are given direct by a simple geometrical transformation of this network. A method is thus derived for calculating the obliquities of the force acting on each contact, this obliquity being the sum of a hydrostatic obliquity and a distortional obliquity. ln conclusion, it is established that for securing equilibrium conditions in the grains the obliquity in each contact must not to exceed the corresponding angle of friction.