From Particle to Material Behavior: the Paths Chartered by Jean Biarez - Multiscale Geomechanics: From Soil to Engineering Projects - page 16

materials (Schneebeli rolls or similar materials). Another possible approach was
based on analytical calculations that could be carried out on simple arrays made of
circular cylinders. These approaches often led to the development of qualitative
analyses that provided a better understanding of the physical bases of a complex
reality.
Of all the research topics developed by Jean Biarez we present the following:
- contact anisotropy;
- the evolution of the orientation of contact forces;
- the balance in local arrays of particles;
- the influence of particle breakage on the behavior of a granular material
considered at the REV scale.
In addition to each of these points, some aspects of contemporary research
results are presented. Today an approach of primary relevance for the scientific
themes enumerated above is numerical discrete modeling, which has been developed
into a tool called the discrete element method (DEM) based on the pioneering work
by Cundal [CUN 79]. This very powerful tool has notably allowed us to surpass the
pioneering work of Jean Biarez; particularly, to work on materials that are much
closer to real materials, and above all to access the vast number of local variables far
more easily. The main new results presented in this chapter are based on results
obtained from this technique of numerical modeling.
Figure 2.2. Example of a loose sample of two-dimensional granular
material made from non convex particles cut in a PVC
plate 2 mm thick [WIE 64]