Characterization of rock cracking patterns in diametral compression tests by acoustic emission and petrographic analysis

Rodrı́guez, Patricia Martı́n; Arab, Paola Bruno; Celestino, Tarcísio Barreto

doi:10.1016/j.ijrmms.2015.12.017

Cited by 93 publications

(28 citation statements)

References 45 publications

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“…Petroš (2005, 2009) studied the influence of strain amplitude and frequency on the fatigue and energy characteristics of sandstone under cyclic loadings. Rodríguez et al (2016) analyzed the evolution law of crack expansion under different loading-unloading paths from the perspective of energy. According to the relationship between the area of the hysteresis loop of the stress-strain curve obtained under cyclic loadings and the dissipated energy (Xiao et al, 2010), the area enclosed by the axial stress-strain curve and the strain in a cyclic loading stage is the unit volume energy E v .…”

Section: Energy Evolution Analysismentioning

confidence: 99%

“…To explore fatigue deformation and tip fracture of fractured rocks, Yang et al (2017) carried out cyclic loading tests on prefabricated double-fractured rock and analyzed the initiation, expansion, and penetration process of a crack group under cyclic loadings. Rodríguez et al (2016) carried out loading-unloading splitting tests on marble disks containing micro-fissures, studied the development and evolution process of micro-cracks, and found that the cracking process is brittle, explosive, and localized. By studying the crack propagation and condensation behavior in rock materials, Lin et al (2019), Zhao C. et al (2019, and Cheng et al (2016) found that the crack opening has a significant impact on the crack initiation stress and path.…”

Section: Introductionmentioning

confidence: 99%

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Fatigue Deformation and Energy Change of Single-Joint Sandstone After Freeze-Thaw Cycles and Cyclic Loadings

et al. 2019

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In cold regions, saturated fractured rock is prone to crack initiation, extension, and branching along the original fracture end under the effect of freeze-thaw (F-T) cycles and cyclic fatigue loadings. The resulting strength deterioration is accompanied by large amounts of pore growth, which results in localized damage and fracturing along the crack end and even causes overall failure. To study the fatigue damage behaviors of fractured rocks under F-T cycles and cyclic loadings, single-joint quasi-sandstone specimens with joint angles of 45 • and 90 • were prepared. Subsequently, F-T damage tests with 0, 10, and 20 cycles and cyclic loading tests with different stress levels were performed. The F-T damage features are discussed based on the binarization image of localized damage along the joint ends and their wave velocity variations. It is found that the frost damage of single-joint quasi-sandstone tends toward a strip with localized fatigue characteristics. Moreover, the changes of strain compliance and dissipated energy are studied under the effect of loading-unloading fatigue. Some of the interesting phenomena observed are as follows: (i) during the early stage of cyclic loading, the joint can be compacted; nevertheless, it tends to expand along the fracture direction once it passes the elastic stage, and the irreversible plastic deformation is stable at this stage. (ii) The cracks caused by F-T damage in the 45 • single-joint samples deflect along the fracture direction, in contrast to the 90 • single-joint specimens. Moreover, the samples with a 45 • single joint are more susceptible to original fracture at the early stage of the failure process, which results in a different failure mode from that of the 90 • single-joint samples. (iii) The F-T cycles and cyclic loadings have a coupling effect on the single-joint sandstone. The strain compliance and hysteresis energy keep increasing uniformly after the F-T cycles and cyclic loadings.

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Section: Energy Evolution Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fatigue Deformation and Energy Change of Single-Joint Sandstone After Freeze-Thaw Cycles and Cyclic Loadings

et al. 2019

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“…The microscale structure of geomaterials contains minerals, pores, and fractures of complex shapes that evolve as a result of coupled fluid, heat, mechanics, and chemical reactions. In order to understand such dynamic multiphysics problems, in the past decade, new technologies have been developed for visualization and characterization of the multiphysics processes of geomaterials at the pore scale, microscale, and even smaller scales [16,20,31,33,38].…”

Section: Introductionmentioning

confidence: 99%

Microscale mechanical modeling of deformable geomaterials with dynamic contacts based on the numerical manifold method

Rutqvist

2020

Comput Geosci

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Micromechanical modeling of geomaterials is challenging because of the complex geometry of discontinuities and potentially large number of deformable material bodies that contact each other dynamically. In this study, we have developed a numerical approach for micromechanical analysis of deformable geomaterials with dynamic contacts. In our approach, we detect contacts among multiple blocks with arbitrary shapes, enforce different contact constraints for three different contact states of separated, bonded, and sliding, and iterate within each time step to ensure convergence of contact states. With these features, we are able to simulate the dynamic contact evolution at the microscale for realistic geomaterials having arbitrary shapes of grains and interfaces. We demonstrate the capability with several examples, including a rough fracture with different geometric surface asperity characteristics, settling of clay aggregates, compaction of a loosely packed sand, and failure of an intact marble sample. With our model, we are able to accurately analyze (1) large displacements and/or deformation, (2) the process of high stress accumulated at contact areas, (3) the failure of a mineral cemented rock samples under high stress, and (4) post-failure fragmentation. The analysis highlights the importance of accurately capturing (1) the sequential evolution of geomaterials responding to stress as motion, deformation, and high stress; (2) large geometric features outside the norms (such as large asperities and sharp corners) as such features can dominate the micromechanical behavior; and (3) different mechanical behavior between loosely packed and tightly packed granular systems.

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“…Portanto, um pó fluxante ao se cristalizar reduz sensivelmente o fluxo de calor da placa/molde [3,7]. A petrologia é uma área da geologia que utiliza a microscopia ótica para identificação de minerais, através de lâminas delgadas e microscópico ótico de luz transmitida [8,9]. A lâmina delgada ou seção delgada consiste na colagem da rocha na lâmina de vidro com posterior polimento com pó abrasivo até a espessura desejada de 0,03 mm.…”

Section: Introductionunclassified

Uso Da Microscopia De Luz Transmitida Na Caracterizaçao De Fluxantes

Carvalho¹,

Martins²,

Alves³

et al. 2017

Anais Do Seminário De Aciaria, Fundição E Metalurgia De Não-Ferrosos

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ResumoOs pós fluxantes consistem de uma mistura de minerais que em contato com o aço líquido, devem fundir e gerar uma escória líquida com características específicas para cada condição de lingotamento. Possuem, como base, o sistema CaO-SiO2-Al2O3-Na2O-CaF2 e podem conter MgO, Li2O, K2O e B2O3. Este trabalho propõe caracterizar os pós fluxantes comerciais baixo carbono e peritético através da microscopia ótica de luz transmitida usando os mesmos procedimentos de descrição de lâminas delgadas para rochas e minerais. Os resultados mostraram a formação de grãos e fase cristalina bem definidas para o peritético e a fase amorfa para o baixo carbono. Em trabalhos futuros esta técnica melhor desenvolvida poderá servir para quantificar o nível de cristalinidade dos fluxantes com maior precisão. Palavras-chave:Pós Fluxante; Lâmina Delgada; Lingotamento; Microscopia óptica. TRANSMITTED LIGHT MICROSCOPY USE IN FLUXING CHARACTERISATION AbstractThe casting powder consists of a mixture of minerals in contact with the liquid steel must merge and produce a liquid slag with specific characteristics for each casting condition. Feature based on the CaO-SiO 2 -Al 2 O 3 -Na 2 O-CaF 2 system and may contain MgO, Li 2 O, K 2 O, B 2 O 3 . This work aims to characterize the post commercial low carbon fluxes and peritectic through the optical transmitted light microscopy using the same Description of thin sections of procedures for rocks and minerals. The results showed the formation of grains and well-defined crystalline phase to the amorphous phase and peritectic to low carbon. In future work best developed this technique may serve to quantify the level of crystallinity of the fluxes accurately.

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Characterization of rock cracking patterns in diametral compression tests by acoustic emission and petrographic analysis

Cited by 93 publications

References 45 publications

Fatigue Deformation and Energy Change of Single-Joint Sandstone After Freeze-Thaw Cycles and Cyclic Loadings

Fatigue Deformation and Energy Change of Single-Joint Sandstone After Freeze-Thaw Cycles and Cyclic Loadings

Microscale mechanical modeling of deformable geomaterials with dynamic contacts based on the numerical manifold method

Uso Da Microscopia De Luz Transmitida Na Caracterizaçao De Fluxantes

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