^ Relationship between Brittleness Index and Crack Initiation Stress Ratio for Different Rock Types | Structurae
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Relationship between Brittleness Index and Crack Initiation Stress Ratio for Different Rock Types

Auteur(s):



Médium: article de revue
Langue(s): anglais
Publié dans: Advances in Civil Engineering, , v. 2020
Page(s): 1-12
DOI: 10.1155/2020/8091895
Abstrait:

Brittleness and crack initiation stress (σci) are important rock mechanical properties and intrinsically related to rock deformation and failure. We establish the relationship betweenσciand uniaxial tensile strength (σt) based on the Griffith stress criterion of brittle failure and introduce brittleness indexesB1B4based on the ratio of uniaxial compressive strength (σc) toσt. The crack initiation stress ratio (K) is defined as the ratio ofσcito crack damage stress. The relationship between brittleness index andKis obtained from laboratory mechanics tests including uniaxial compression and Brazilian splitting tests. The results show thatB1andB2have an inversely proportional and variant inversely proportional relationship withK, respectively, whereas no apparent relationship is observed betweenB3andB4andK. The fitting of experimental data from igneous, metamorphic, and sedimentary rocks shows thatB1andB2have a power and linear relationship withK, respectively, whereas no functional relationship is observed betweenB3andB4andK. We collected 70 different types of uniaxial compression test data for igneous, metamorphic, and sedimentary rocks and obtained laws that are consistent within each rock type. The experimental data are used to verifyKestimations using a specified constantαbased on the experimental data. According to results of the limestone tests,α = 3 forσc < 60 MPa (high porosity),α = 5 for 60 MPa ≤ σc ≤ 90 MPa (moderate porosity), andα = 8 forσc > 90 MPa (low porosity) as well as for igneous and metamorphic rocks. Estimates ofKfor 127 different rock types using the newly defined brittleness index are in good agreement with the experimental results. This study provides an important new brittleness index calculation method and a simple and reliable method for estimatingK.

Copyright: © Juyu Jiang et al.
License:

Cette oeuvre a été publiée sous la license Creative Commons Attribution 4.0 (CC-BY 4.0). Il est autorisé de partager et adapter l'oeuvre tant que l'auteur est crédité et la license est indiquée (avec le lien ci-dessus). Vous devez aussi indiquer si des changements on été fait vis-à-vis de l'original.

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  • Reference-ID
    10421181
  • Publié(e) le:
    02.05.2020
  • Modifié(e) le:
    02.06.2021