The Acoustic Emission Characteristics and Shear Behaviour During Granular Shearing

Rapid landsliding phenomena demonstrate that their constituent grains can flow with extremely low friction along their runout paths. Over the past several decades, many studies have been motivated to reveal such kind of unusual physical process; however, the progressive maturation of these events is still lack of enough scientific evidence. Modern insight into the granular dynamics indicates that the force fluctuations may be in behaviour of abrupt perturbations of internal forces and release of strain energy. Remarkably, such energy release events are manifested in the generation of elastic waves, termed acoustic emissions (AE), which deliver invaluable information concerning the granular deformations. We thus employed a high frequency range of AE sensor to capture the elastic waves and examined the relationships between characteristics of AE and fluctuations of shear resistance. Our results suggested that there was a strong correlation between shear resistance drops and AE events; the characteristics and occurrence rates of generated AE events were influenced not only by shear velocity but also by particle size. The drops of shear resistance and the amplitude of AE waveforms were greater with increase of particle size, and the AE rates increase with increase of shear velocity.