ABSTRACT
To identify the accessible configurations at the grain level and to understand which are the possible combinations of such local configurations which generate the global packing is of singular importance, hence it is the necessary starting point for any fundamental understanding of granular matter. Until now the empirical investigation of the geometrical structure of granular packings have been limited by the paucity of accurate experimental data. Indeed, after the seminal works of Bernal & Mason (1960) and Scott (1962), it has been only very recently that the use of tomography has allowed one to ‘see’ the three dimensional structure of such systems and explore their geometry from the grain level up to the whole packing (Seidler et al. 2000; Sederman et al. 2001; Richard et al. 2003; Aste et al. 2004; Aste et al. 2005).
