Micromechanical correlation between elasticity and strength characteristics of anisotropic rocks

Pouragha, Mehdi; Eghbalian, Mahdad; Wan, Richard

doi:10.1016/j.ijrmms.2019.104154

Cited by 14 publications

(12 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In sedimentary or metamorphic rocks, the layering of minerals strongly a↵ects joint family characteristics, bonds, and fissuring (i.e., an inherent geometrical anisotropy is imprinted in these materials by formation, tear and wear). Ultimately, the mechanical behavior of anisotropic rocks may strongly vary due to the layering properties and the loading orientation on rock samples [1][2][3][4][5]. Typically, the failure strength of rock cores presenting an anisotropic inner structure is tested under diametral point load, also known as the brazilian test in which the loading orientation is varied from totally aligned to the layering up to orthogonal.…”

Section: Introductionmentioning

confidence: 99%

“…More recently, numerical methods, mostly based on the discrete-element approach, have been employed to model and analyze the behavior of anisotropic rock given its capabilities of reproducing failure and crushing (see, for instance, Refs. [5,6]). These methods have added valuable information concerning the modeling and failure mechanism of anisotropic brittle structures.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Strength and energy consumption of inherently anisotropic rocks at failure

2021

View full text Add to dashboard Cite

Using a discrete-element approach and a bonding interaction law, we model and test crushable inherently anisotropic structures reminiscent of the layering found in sedimentary and metamorphic rocks. By systematically modifying the level of inherent anisotropy, we characterize the evolution of the failure strength of circular rock samples discretized using a modified Voronoi tesselation under diametral point loading at different orientations relative to the sample’s layers. We characterize the failure strength, which can dramatically increase as the loading becomes orthogonal to the rock layers. We also describe the evolution of the macroscopic failure modes as a function of the loading orientation and the energy consumption at fissuring. Our simulation strategy let us conclude that the length of bonds between Voronoi cells controls the energy being consumed in fissuring the rock sample, although failure modes and strength are considerably changing. We end up this work showing that the microstructure is largely affected by the level of inherent anisotropy and loading orientation.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Strength and energy consumption of inherently anisotropic rocks at failure

2021

View full text Add to dashboard Cite

show abstract

“…In sedimentary or metamorphic rocks, the layering of minerals strongly affects joint family characteristics, bonds, and fissuring (i.e., an inherent geometrical anisotropy is imprinted in these materials by formation, tear and wear). Ultimately, the mechanical behavior of anisotropic rocks may strongly vary due to the layering properties and the loading orientation on rock samples [1][2][3][4][5]. Typically, the failure strength of rock cores presenting an anisotropic inner structure is tested under diametral point load, also known as the brazilian test in which the loading orientation is varied from totally aligned to the layering up to orthogonal.…”

Section: Introductionmentioning

confidence: 99%

Strength and energy consumption of inherently anisotropic rocks at failure

Cantor,

Ovalle,

Azéma

2021

Preprint

View full text Add to dashboard Cite

Using a discrete-element approach and a bonding interaction law, we model and test crushable inherently anisotropic structures reminiscent of the layering found in sedimentary and metamorphic rocks. By systematically modifying the level of inherent anisotropy, we characterize the evolution of the failure strength of circular rock samples discretized using a modified Voronoi tesselation under diametral point loading at different orientations relative to the sample's layers. We characterize the failure strength, which can dramatically increase as the loading becomes orthogonal to the rock layers. We also describe the evolution of the macroscopic failure modes as a function of the loading orientation and the energy consumption at fissuring. Our simulation strategy let us conclude that the length of bonds between Voronoi cells controls the energy being consumed in fissuring the rock sample, although failure modes and strength are considerably changing. We end up this work showing that the microstructure is largely affected by the level of inherent anisotropy and loading orientation.

show abstract

“…If any of those fabric properties present a preferred orientation or organization in space, then the material can be considered inherently anisotropic. Many studies have focused on the quantification of the level of inherent fabric anisotropy in rocks or on the impact of the loading orientation on the ultimate strength of such layered materials (Hoek, 1964;Oda, 1982;Amadei, 1996;Chen et al, 1998;Zhang and Einstein, 2000;Karakul et al, 2010;Khanlari et al, 2015;Guha Roy and Singh, 2016;Pouragha et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

“…For rocks not presenting an inherent anisotropy, the failure strength is independent of the loading orientation . However, for highly layered rocks such as slate, schist or shale, the failure strength largely varies with in a 'U' shape with minimal strength for an orientation around ≃ 25 • , and increasing strength as → 0 • or 90 • (Amadei, 1996;Saroglou and Tsiambaos, 2008;Karakul et al, 2010;Saeidi et al, 2014;Garagon and Çan, 2010;Pouragha et al, 2020;Xu et al, 2020). As shown early by Hoek in 1964, the 'U' shape is consistent with Griffith's theory of brittle fracture of materials, in which the maximum stress at the tip of the crack triggers the propagation of a fissure once a critical amount of energy is added to the system.…”

Section: Introductionmentioning

confidence: 99%

Microstructural origins of crushing strength for inherently anisotropic brittle materials

Cantor¹,

Ovalle²,

Azéma³

2021

Preprint

View full text Add to dashboard Cite

We study the crushing strength of brittle materials whose internal structure (e.g., mineral particles or graining) presents a layered arrangement reminiscent of sedimentary and metamorphic rocks. Taking a discrete-element approach, we probe the failure strength of circular-shaped samples intended to reproduce specific mineral configurations. To do so, assemblies of cells, products of a modified Voronoi tessellation, are joined in mechanically-stable layerings using a bonding law. The cells' shape distribution allows us to set a level of inherent anisotropy to the material. Using a diametral point loading, and systematically changing the loading orientation with respect to the cells' configuration, we characterize the failure strength of increasingly anisotropic structures. This approach ends up reproducing experimental observations and lets us quantify the statistical variability of strength, the consumption of the fragmentation energy, and the induced anisotropies linked to the cell's geometry and force transmission in the samples. Based on a fine description of geometrical and mechanical properties at the onset of failure, we develop a micromechanical breakdown of the crushing strength variability using an analytical decomposition of the stress tensor and the geometrical and force anisotropies. We can conclude that the origins of failure strength in anisotropic layered media rely on compensations of geometrical and mechanical anisotropies, as well as an increasing average radial force between minerals indistinctive of tensile or compressive components.

show abstract

Micromechanical correlation between elasticity and strength characteristics of anisotropic rocks

Cited by 14 publications

References 27 publications

Strength and energy consumption of inherently anisotropic rocks at failure

Strength and energy consumption of inherently anisotropic rocks at failure

Strength and energy consumption of inherently anisotropic rocks at failure

Microstructural origins of crushing strength for inherently anisotropic brittle materials

Contact Info

Product

Resources

About