2012/08/31 by Florent Gimbert, F. Gimbert, David Amitrano +3 · 1 citation
Engineering · Materials Science · Physics and Astronomy · #Compressibility #Crossover #Flow (mathematics) #Geotechnical Engineering and Soil Mechanics #Granular flow and fluidized beds #Granular material #Inertial frame of reference #Instability #Material Dynamics and Properties #Shear (geology) #Shear band #Shear stress #cond-mat.soft #cond-mat.stat-mech
paper · pdf · doi:10.1209/0295-5075/104/46001
arxiv created 2013/05/15 · openalex publication_date 2013/11/01 · arxiv updated 2015/06/11 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Being ubiquitous in a large variety of geomaterials, granular assemblies play a crucial role in the mechanical stability of engineering and geophysical structures. For these applications, an accurate knowledge of the processes at the origin of shear localization, i.e. faulting, in frictional granular assemblies submitted to compressive loading is needed. Here we tackle this problem by performing discrete-element numerical simulations. A thorough analysis of the evolution of multi-scale mechanical properties as approaching sample macroscopic instability is performed. Spatial correlations operating within the shear stress and strain fields are analyzed by means of a coarse-graining analysis. The divergence of correlation lengths is reported on both shear stress and strain fields as approaching the transition to sample instability. We thus show that the crossover from a quasi-static regime where the sample deforms infinitely slowly to a dense flow regime, where inertial forces play a significant role, can be interpreted as a critical phase transition. At this transition, no shear band of characteristic thickness can be defined.