Brittle Damage Processes Around Equi‐Dimensional Pores or Cavities in Rocks: Implications for the Brittle‐Ductile Transition
Name
JGR Solid Earth - 2024 - Bernabé - Brittle Damage Processes Around Equi‐Dimensional Pores or Cavities in Rocks .pdf
Description
Published version
Size
3.95 MB
Format
Adobe PDF
Checksum (MD5)
850c0317ef32517dbaefec176cb60c63
Author(s)
Bernabé, Yves
Peč, Matěj
Date Issued
May 28, 2024
Journal
Journal of Geophysical Research: Solid Earth
Publisher
American Geophysical Union
Citation
Bernabé, Y., & Peč, M. (2024). Brittle damage processes around equi-dimensional pores or cavities in rocks: Implications for the brittle-ductile transition. Journal of Geophysical Research: Solid Earth, 129, e2024JB028814.
Version
Final published version
Abstract
In the Earth's upper crust, rocks deform mostly by means of brittle fracturing processes. At the micro‐scale these processes involve the formation and growth of microcracks in the vicinity of defects such as open fissures, pores and other cavities. Large defects can produce strong enough perturbations of the stress field to activate and/or intensify brittle damage around them. Here we considered the ideal cases of smooth cylindrical and spherical pores inside an infinite solid body subjected to remote triaxial compressive stresses (i.e., the intermediate and minimum principal stresses are assumed equal). We first established the resulting local stress field around one of those large pores and then verified whether certain brittle damage processes could be activated in these conditions. We mainly considered the formation of tensile microcracks and micro shear bands. The former requires the presence of tensile stresses in some regions around the pore, while the latter needs sufficiently large shear stresses on pre‐existing optimally inclined microcracks to overcome their frictional resistance to sliding. We find that shear driven deformation remains localized in the vicinity of the pore. On the other hand, dilatational, tensile cracks can propagate large distances away from the pore but cannot form at and above some threshold ratio of the least to the largest principal stresses. Faulting associated with interacting tensile cracks is therefore suppressed with increasing depth. Our analysis leads to conclusions generally consistent with published experimental observations and provides some clues to discuss the physical cause of the brittle‐ductile transition in rocks.
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Creative Commons Attribution-NonCommercial
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DOI of Published Version
https://doi.org/10.1029/2024JB028814
