Factors Affecting Crack Initiation in Low Porosity Crystalline Rocks

Nicksiar, Mohsen; Martin, C. Derek

doi:10.1007/s00603-013-0451-2

Cited by 157 publications

(60 citation statements)

References 39 publications

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“…One plausible explanation was due to definition of the CI stress. In this paper, Poisson's ratio method was used to obtain the crack initiation stress [19]. But in actual operation, the CI stress is defined with 10% change of Poisson's ratio in some models.…”

Section: Discussionmentioning

confidence: 99%

“…Change in Poisson's ratio at crack initiation stress (b) Figure 9: The methods used to establish crack initial stress and crack damage stress [19]. discussed.…”

Section: Poisson's Ratiomentioning

confidence: 99%

“…discussed. Nicksiar and Martin (2012) [19] reviewed the various methods about crack initiation stress in previous literatures. In this study, Poisson's ratio method was used to obtain the crack initiation stress (see Figure 9(b)).…”

Section: Poisson's Ratiomentioning

confidence: 99%

“…The ratio remains constant until cracking occurs. The stress associated with the change in Poisson's ratio is referred to as the CI stress [19,36]. And the volumetric strain method was used to obtain the damage stress (see Figure 9(a)).…”

Section: Poisson's Ratiomentioning

confidence: 99%

“…When the unstable crack begins to grow, the volumetric strain reaches maximum. The stress associated with maximum volumetric strain is referred to as the CD stress [19,37,38]. In general, Poisson's ratio and volumetric strain are calculated based on the lateral and axial strains.…”

Section: Poisson's Ratiomentioning

confidence: 99%

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A Numerical Research on Crack Process of Gypsum Containing Single Flaw with Different Angle and Length in Uniaxial Loading

Dai

Zhang

2018

Shock and Vibration

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To investigate the crack behaviour of rock or rock-like material in uniaxial loading, a series of numerical simulations were conducted on gypsum specimens containing a single flaw with different inclination angle (0 ∘ -90 ∘ ) and length (10 mm-30 mm). Based on the numerical simulations results, the effect of flaw length on peak strength, the CI stress, and the CD stress were investigated with different inclination angles. The results show that the peak strength decreased initially and then increased with increasing of the flaw angle. Meanwhile, the peak strength decreased gradually when the length of the preexisting flaw increased. When the inclination angle was 30 ∘ , 45 ∘ , and 60 ∘ , the reduction degree of peak strength increased with increasing of the flaw length. The CI stress and CD stress not only depend on the inclination angle but also depend on flaw length. Four types of crack were observed in numerical simulations. The present research facilitates increased understanding of crack behaviour of rock under different conditions.

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Section: Discussionmentioning

confidence: 99%

“…Change in Poisson's ratio at crack initiation stress (b) Figure 9: The methods used to establish crack initial stress and crack damage stress [19]. discussed.…”

Section: Poisson's Ratiomentioning

confidence: 99%

Section: Poisson's Ratiomentioning

confidence: 99%

Section: Poisson's Ratiomentioning

confidence: 99%

Section: Poisson's Ratiomentioning

confidence: 99%

See 3 more Smart Citations

A Numerical Research on Crack Process of Gypsum Containing Single Flaw with Different Angle and Length in Uniaxial Loading

Dai

Zhang

2018

Shock and Vibration

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Influence of grain size heterogeneity on strength and microcracking behavior of crystalline rocks

2017

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This study numerically investigates the influence of material heterogeneity on the strength and deformation behavior and the associated microcracking process of a felsic crystalline rock using a grain‐based modeling approach in two‐dimensional Particle Flow Code. By using a heterogeneity index defined in this study, the heterogeneity induced by variation of grain size distribution can be explicitly incorporated into the numerical specimen models quantitatively. Under compressive loading, the peak strength and the elastic modulus are found to increase as the numerical model gradually changes from heterogeneous to homogeneous, i.e., a decrease of heterogeneity index. Meanwhile, the number of grain boundary tensile cracks gradually decreases and the number of intragrain cracks increases at the moment of failure. However, the total number of generated microcracks seems not to be significantly influenced by heterogeneity. The orientation of grain boundary microcracks is mainly controlled by the geometry of assembled grain structure of the numerical specimen model, while the orientation of intragrain microcracks is to a large degree influenced by the confinement. In addition, the development of intragrain cracks (both tensile and shear) is much more favored in quartz than in other minerals. Under direct tensile loading, heterogeneity is found to have no significant influence on the simulated stress‐strain responses and rock strength. Only grain boundary tensile cracks are generated when the numerical models are loaded in direct tension, and the position of generated macroscopic fracture developed upon failure of the specimen is largely affected by heterogeneity.

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Investigation of microcracking behaviors in brittle rock using polygonal grain‐based distinct method

Wang

et al. 2021

Num Anal Meth Geomechanics

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The failure process in brittle rocks is an important topic in rock mechanics, whose good understanding assists in predicting the strength and deformation characteristics of rocks. Because it is difficult to directly observe microcracks in laboratory tests, a numerical model is a useful tool for investigating microcracking behaviors. However, the mechanism of microcrack evolution is still unclear at the grain scale considering the microscopic heterogeneities. This paper proposes a polygonal universal distinct element code grain‐based model to solve this problem. Compared with other grain‐based models, this model is different in that mineral grains are subdivided into polygon blocks. The grain size, composition, and bond types of the contacts are incorporated, and both inter‐ and intra‐grain cracks are mimicked. Subsequently, micro‐parameters of the blocks and contacts are carefully calibrated according to the laboratory results. Following this, the calibrated model is employed to study the microcracking behaviors of granite in unconfined compression, confined compression, and Brazilian splitting tests. Both the cumulative numbers and locations of microcracks in different grains are recorded, and the types of macroscopic fractures are identified. The modeling results show that tensile cracks dominate the generated microcracks in the low confined compression tests, and the macroscopic fracture pattern is axial splitting. Shear cracks are dominant in the high confined compression tests, and the macroscopic failure pattern is X‐type shear failure. The simulated results are consistent with those observed in the laboratory tests, and thus, may assist in improving rock acoustic emission monitoring and understanding the damage process of rock.

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Factors Affecting Crack Initiation in Low Porosity Crystalline Rocks

Cited by 157 publications

References 39 publications

A Numerical Research on Crack Process of Gypsum Containing Single Flaw with Different Angle and Length in Uniaxial Loading

A Numerical Research on Crack Process of Gypsum Containing Single Flaw with Different Angle and Length in Uniaxial Loading

Influence of grain size heterogeneity on strength and microcracking behavior of crystalline rocks

Investigation of microcracking behaviors in brittle rock using polygonal grain‐based distinct method

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