Microstructural Controls on the Uniaxial Compressive Strength of Porous Rocks Through the Granular to Non‐Granular Transition

Carbillet, Lucille; Wadsworth, Fabian B.; Heap, Michael J.; Baud, Patrick

Abstract

Under uniaxial compression, a porous rock fails by coalescence of stress‐induced microcracks. The micromechanical models developed to analyze uniaxial compressive strength data consider a single mechanism for the initiation and propagation of microcracks and a fixed starting microstructure. Because the microstructure of clastic porous rock transitions from granular to non‐granular as porosity decreases during diagenesis, their strength cannot be captured by a single model. Using synthetic samples with independently controlled porosity and initial grain radius we show that high‐porosity granular samples, where microcracks grow at grain‐to‐grain contacts, are best described by a grain‐based model. Low‐porosity non‐granular samples, where microcracks grow from pores, are best described by a pore‐based model. The switch from one model to the other depends on porosity and grain radius. We propose a regime plot that indicates which micromechanical model may be more suitable to predict strength for a given porosity and grain radius.

Citation

Carbillet, L., Wadsworth, F. B., Heap, M. J., & Baud, P. (2023). Microstructural Controls on the Uniaxial Compressive Strength of Porous Rocks Through the Granular to Non‐Granular Transition. Geophysical Research Letters, 50(21), Article e2023GL104678. https://doi.org/10.1029/2023gl104678

• Journal Article Type: Letter
• Acceptance Date: Oct 23, 2023
• Online Publication Date: Nov 2, 2023
• Publication Date: Nov 16, 2023
• Deposit Date: Nov 10, 2023
• Publicly Available Date: Nov 10, 2023
• Journal: Geophysical Research Letters
• Print ISSN: 0094-8276
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 50
• Issue: 21
• Article Number: e2023GL104678
• DOI: https://doi.org/10.1029/2023gl104678
• Public URL: https://durham-repository.worktribe.com/output/1883710