Résumé
By means of three-dimensional Contact Dynamics (CD) simulations, we investigate themicrostructural properties of sheared granular packings by varying systematically the inertialnumber I from the quasi-static regime, to the intermediate dense flow and collisional regime[1]. A detailed analysis of the connectivity of the particles reveals that the transition betweenthe regimes is correlated to profound changes of the nature of the contact network. Inparticular, we show that the increase of friction angle with inertial number is only aconsequence of contact anisotropy. As the inertial number increases, the role of force chainsdecrease and that of friction mobilization increases as long as percolating force chains arepresent in the system. Beyond this point, which corresponds to an inertial number I0~0.25,the force anisotropies do not evolve with the inertial number.