Particle crushing: Passive detection

When the confining pressure is sufficiently large, soil grain breakage can occur and this can have a significant influence on the performance of a wide range of geotechnical systems such as shallow foundations, embankments and dams, railway substructures. However, the mechanics of particle crushing still remains one of the most difficult problems in geomechanics, while the link between the breakage of particles and the mechanical response of the soil through adequate continuum constitutive models has not been solved satisfactorily. This study investigates the possibility of using Acoustic Emission (AE) technique to predict the extent of soil particle breakage and its evolution under loading. Insight into the use of AE to characterize the breakage signature of particles is gained through testing of individual glass spherical particles of different sizes. It is shown that the frequency content of the AE breakage signals does not appear to be affected by the particle size and that suggests that the AE can be directly linked to a typical particle breakage mechanism. At the breakage point all the glass particles disintegrate instantly into small pieces.