This thesis describes a new technique for monitoring the transient stiffness of a sand specimen while it undergoes crushing in a die inside which lies the piezotransducer. The breakage events generate waves that excite the piezotransducer, the response of which depends on the transient stiffness and density of the crushing soil (hence the term transient stiffness). Laboratory experiments and numerical simulations validate the technique and offer insight into the mechanics of comminuting granular assemblies.
