Volume 28, Issue 5 (September 2005)
Behavior of Granular Assemblies at High Velocity in a Large Open Shear Box
Large open shear box tests on granular materials have been conducted to investigate the behavior of these materials at high velocity. Several modes of kinetic motion were identified from the tests: steady sliding, sliding with rolling, impulsive rolling, and steady rolling. The measured resistances in these tests of different modes were observed to be dependent on material friction, base friction, velocity, body shape, and mobilized volume. However, spectral analysis of the measured data in time series shows that there exist no periodicities in the spectra, i.e., frequency- or velocity-independent. Of practical implication for this study is that the measured resistance for constant velocity motion decreases with increasing rolling motion activity within the moving granular mass. The average coefficient of resistance or friction could be less than the coefficient of kinetic friction measured in Coulomb-type shear tests.