The Influence of Grain Size Distribution on Mechanical Compaction and Compaction Localization in Porous Rocks - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Geophysical Research : Solid Earth Année : 2022

The Influence of Grain Size Distribution on Mechanical Compaction and Compaction Localization in Porous Rocks

Résumé

The modes of formation of clastic rocks result in a wide variety of microstructures, from poorly-sorted heterogeneous rocks to well-sorted and nominally homogeneous rocks. The mechanical behavior and failure mode of clastic rocks is known to vary with microstructural attributes such as porosity and grain size. However, the influence of the grain size distribution, in particular the degree of polydispersivity or modality of the distribution, is not yet fully understood, because it is difficult to study experimentally using natural rocks. To better understand the influence of grain size distribution on the mechanical behavior of porous rocks, we prepared suites of synthetic samples consisting of sintered glass beads with polydisperse grain size distributions. We performed hydrostatic compression experiments and found that, all else being equal, the onset of grain crushing occurs much more progressively and at lower pressure in polydisperse synthetic samples than in monodisperse samples. We conducted triaxial experiments in the regime of shear-enhanced compaction and found that the stress required to reach inelastic compaction was lower in polydisperse samples compared to monodisperse samples. Further, our microstructural observations show that compaction bands developed in monomodal polydisperse samples while delocalized cataclasis developed in bimodal polydisperse samples, where small grains were systematically crushed while largest grains remained intact. In detail, as the polydispersivity increases, microstructural deformation features appear to transition from localized to delocalized through a hybrid stage where a compaction front with diffuse bands propagates from both ends of the sample toward its center with increasing bulk strain.
Fichier principal
Vignette du fichier
Carbillet et al. J.Geophys.Res. 2022.pdf (6.77 Mo) Télécharger le fichier
Origine : Publication financée par une institution

Dates et versions

hal-03845703 , version 1 (09-11-2022)
hal-03845703 , version 2 (04-05-2023)

Identifiants

Citer

Lucille Carbillet, Michael J Heap, Patrick Baud, Fabian B Wadsworth, Thierry Reuschlé. The Influence of Grain Size Distribution on Mechanical Compaction and Compaction Localization in Porous Rocks. Journal of Geophysical Research : Solid Earth, 2022, 127 (11), pp.e2022JB025216. ⟨10.1029/2022JB025216⟩. ⟨hal-03845703v2⟩
13 Consultations
24 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More