ABSTRACT
The number of beads implied in a slip event and the nature of the bead displacements are not attainable with a macroscopic technique such as the triaxial test. That is why acoustical sensors have been added to the experiment in order to study the length of sliding, the number of beads involved and their geometry. Figure 1 shows the acoustic set-up added to the sample placed in a press. Using the diffusion property of a bead packing, we realize ultrasonic non destructive test on the glass bead sample. Ultrasound diffusion results from multiple wave scattering, propagation and interferences (Jia, 2004).
