Influences of structural anisotropy and heterogeneity on three-dimensional strain fields and cracking patterns of a clay-rich rock

Shi, Hai-Ling; Hosdez, Jérôme; Rougelot, Thomas; Xie, Shouyi; Shao, Jian‐Fu; Talandier, Jean

doi:10.1007/s11440-021-01152-6

Cited by 12 publications

(4 citation statements)

References 48 publications

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“…However, the UCS of the structures with consistent mineral composition is mainly determined by the included angle between the dominant inclusion inclination and loading direction. This finding extends the conclusion in the literature [23] suggesting that the failure strength is strongly dependent on the included angle between the loading direction and bedding planes. The inclusion-matrix interfaces constituted by the dominant inclusions are the mesoscopic structural planes.…”

Section: Discussionsupporting

confidence: 90%

“…Sui et al studied the microstructural deformation of a tight sandstone by the in situ loading/scanning experiment and deformation simulation method [21]. Shi et al investigated the three-dimensional nonuniform strain fields and cracking patterns of claystone by the uniaxial compression creep test, digital volume correlation (DVC) method, and X-ray microtomography [22,23].…”

Section: Introductionmentioning

confidence: 99%

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Structural Damage Evolution of Mesoscale Representative Elementary Areas of Mudstones

Zeng

et al. 2023

Geofluids

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The mechanical behavior of mudstones is significantly affected by their mesostructure. This study investigates the damage evolution of red mudstone mesostructures under uniaxial compression through U-Net image segmentation, mesoscopic representative elementary area (mREA), meso-element equivalent method, and linearly superimposed model. Results show that the mREAs can be simplified as a binary structure comprising nonclayey minerals and a porous matrix. The inclusion-matrix interfaces constituted by the dominant inclusions, such as large inclusions and a series of inclusions with specific arrangements, are the weakest regions at the postpeak stage. The shear failure of these interfaces leads to general shear failure with a penetrating principal fracture or local shear with several nonpenetrating local fractures in the mREAs. The damage evolution and failure mode are sensitive to the inclusion geometric features, e.g., inclination, grain size, and spacing. However, the uniaxial compressive strength (UCS) is mainly determined by the included angle between the dominant inclusion inclination and the loading direction. With consistent composition, an increase in the included angle from 0 to 90° results in an increase in the UCS of the muddy facies and a decrease in the sandy facies, with the UCS of the sandy facies being more sensitive to changes in the included angle. Our findings indicate that the structural failure of red mudstones from mesoscopic to macroscopic is driven by the accumulation and expansion of shear failure at multiple scales due to the presence of hard–soft interfaces. This study enhances our understanding of the structural failure mechanism of mudstones and serves as a practical reference for the mesomechanical testing of clay rocks.

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Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Structural Damage Evolution of Mesoscale Representative Elementary Areas of Mudstones

Zeng

et al. 2023

Geofluids

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“…Transverse isotropy is a common type of anisotropy in which the material properties are symmetric about a bedding plane and anisotropic in the direction normal to this plane 19–23 . The effect of anisotropy on the stiffness and strength of various transversely isotropic rocks has been extensively investigated in the literature 24–31 . The stiffness and strength of transversely isotropic rocks depend on the direction of the load with respect to the orientation of the bedding plane, and are often different in the bed‐normal (BN) and bed‐parallel (BP) directions.…”

Section: Introductionmentioning

confidence: 99%

“…[19][20][21][22][23] The effect of anisotropy on the stiffness and strength of various transversely isotropic rocks has been extensively investigated in the literature. [24][25][26][27][28][29][30][31] The stiffness and strength of transversely isotropic rocks depend on the direction of the load with respect to the orientation of the bedding plane, and are often different in the bed-normal (BN) and bed-parallel (BP) directions. The maximum strength can occur in either direction, but the minimum strength typically occurs when the load is inclined with the bedding plane, often at an angle 𝜃 between 20 and 40 • .…”

Section: Introductionmentioning

confidence: 99%

Evolution of anisotropy with saturation and its implications for the elastoplastic responses of clay rocks

Borja

2021

Num Anal Meth Geomechanics

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Many clay rocks have distinct bedding planes. Experimental studies have shown that their mechanical properties evolve with the degree of saturation (DOS), often with higher stiffness and strength after drying. For transversely isotropic rocks, the effects of saturation can differ between the bed-normal (BN) and bedparallel (BP) directions, which gives rise to saturation-dependent stiffness and strength anisotropy. Accurate prediction of the mechanical behavior of clay rocks under partially saturated conditions requires numerical models that can capture the evolving elastic and plastic anisotropy with DOS. In this study, we present an anisotropy framework for coupled solid deformation-fluid flow in unsaturated elastoplastic media. We incorporate saturation-dependent strength anisotropy into an anisotropic modified Cam-Clay (MCC) model and consider the evolving anisotropy in both the elastic and plastic responses. The model was calibrated using experimental data from triaxial tests to demonstrate its capability in capturing strength anisotropy at various levels of saturation. Through numerical simulations, we demonstrate the role of evolving stiffness and strength anisotropy in the mechanical behavior of clay rocks. Plane strain simulations of triaxial compression tests were also conducted to demonstrate the impacts of material anisotropy and DOS on the mechanical and fluid flow responses.

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Effects of Lithological Layering and Fluid Diffusivity on the Nucleation of Coal Dynamic Failure

Zhong,

Zhang,

Zhang

et al. 2024

Rock Mech Rock Eng

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Influences of structural anisotropy and heterogeneity on three-dimensional strain fields and cracking patterns of a clay-rich rock

Cited by 12 publications

References 48 publications

Structural Damage Evolution of Mesoscale Representative Elementary Areas of Mudstones

Structural Damage Evolution of Mesoscale Representative Elementary Areas of Mudstones

Evolution of anisotropy with saturation and its implications for the elastoplastic responses of clay rocks

Effects of Lithological Layering and Fluid Diffusivity on the Nucleation of Coal Dynamic Failure

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