Influence of bedding planes on fracture characteristics of coal under mode II loading

Zhao, Yixin; Sun, Zhuang; Gao, Yirui; Wang, Xiaoliang; Song, Honghua

doi:10.1016/j.tafmec.2021.103131

Cited by 22 publications

(6 citation statements)

References 55 publications

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“…The distribution of the new area after the coal and rock particles are subjected to hammer drop and grinding is illustrated in Figure 9, with the fitting parameters presented in Table 6. The results demonstrate that Equation (20) adeptly captures the relationship between the newly added surface areas. Equation (20) establishes the distribution mode of new surface areas after particle breakage, which is influenced by the initial particle size and the energy (E 0 ) of a single broken particle.…”

Section: Distribution Of New Areamentioning

confidence: 83%

“…The results demonstrate that Equation (20) adeptly captures the relationship between the newly added surface areas. Equation (20) establishes the distribution mode of new surface areas after particle breakage, which is influenced by the initial particle size and the energy (E 0 ) of a single broken particle. It is evident in Table 6 that, in comparison to non-outburst coal, the parameter values (E 0 ) associated with crushing energy in outburst coal are smaller, suggesting that outburst coal tends to fracture under lower energy conditions.…”

Section: Distribution Of New Areamentioning

confidence: 83%

“…For coal, the fracture toughness measured at different scales and different orientations varies significantly. The fracture toughness of anisotropic materials varies elliptically with the bedding angle [20]. Shi et al considered the co-effects of bedding planes and loading conditions on Mode-I fracture toughness of anisotropic rocks.…”

Section: Introductionmentioning

confidence: 99%

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New Method for Determining Mode-I Static Fracture Toughness of Coal Using Particles

Cheng,

Huang,

Zheng

et al. 2024

Materials

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Understanding the mechanical properties of coal is crucial for efficient mining and disaster prevention in coal mines. Coal contains numerous cracks and fissures, resulting in low strength and challenges in preparing standard samples for testing coal fracture toughness. In engineering, indicators such as the hardness coefficient (f value) and Hardgrove grindability index (HGI) are straightforward to measure. Various experiments, including drop weight, grinding, uniaxial compressive strength and three-point bending experiments, were conducted using notched semi-circular bend (NSCB) specimens and particle sizes of 1–2 mm/0.425–1 mm. Theoretical and experimental results indicate that the hardness coefficient of coal and rock is proportional to the crushing work ratio and inversely proportional to the mean equivalent diameter. Moreover, the square of the fracture toughness of coal and rock is directly proportional to the crushing work ratio, inversely proportional to the newly added area, directly proportional to the mean equivalent diameter and directly proportional to the hardness coefficient. The Mode-I fracture toughness of coal and rock can be rapidly determined through the density, the equivalent diameter after crushing and the elastic modulus, with experimental verification of its accuracy. Considering that smaller particle sizes exhibit greater resistance to breakage, the distribution mode of new surface areas after particle breakage was established, influenced by the initial particle size and the energy of a single broken particle. This study can assist in quickly and accurately determining the fracture toughness of coal.

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Section: Distribution Of New Areamentioning

confidence: 83%

Section: Distribution Of New Areamentioning

confidence: 83%

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New Method for Determining Mode-I Static Fracture Toughness of Coal Using Particles

Cheng,

Huang,

Zheng

et al. 2024

Materials

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show abstract

“…In terms of prediction criteria, many scholars compare the test results of ASCB specimens with different fracture criteria to verify the test result accuracy. Guo [13] and Zhao [14] used acoustic emission technology to analyze the internal damage characteristics, failure modes, and microscopic damage mechanisms of ASCB samples.…”

Section: Introductionmentioning

confidence: 99%

Study on Fracture Characteristics of Layered Sandstone under Asymmetric Loading

Hao,

Zhou,

Liao

et al. 2024

Materials

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In engineering practice, layered rock masses often display obvious anisotropy while deforming and failing, and the failure mode directly impacts the engineering construction stability. In this study, the fracture failure load, fracture toughness, crack deflection angle, and failure mode of a layered rock mass under different fracture modes were analyzed by utilizing improved asymmetric semi-circular disc specimens. According to the constitutive model of transversely isotropic materials, the maximum tensile stress (MTS), maximum energy release rate (MERR), and maximum strain energy density (MSED) calculation formulas were modified, and the calculation formulas of the three prediction criteria under anisotropic materials were derived. The calculation results were compared with the experimental results. The results show that the fracture toughness and crack deflection angle were significantly affected by the weak bedding plane. As a result of applying the MTS criterion, the results are closer to the experimental results, providing a solid foundation for engineering deformation, failure, and fracture analyses.

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“…Du et al 35 investigated the AE evolution and crack classification under several basic laboratory rock tests. Zhao et al 36,37 analyzed the strength, fracture patterns, and failure mechanism of bedding coal under modes I and II loading conditions based on the DIC and AE methods.…”

Section: Introductionmentioning

confidence: 99%

Failure characteristic and acoustic emission spatio‐temporal evolution of coal under different cyclic loading rates

Liu

Zhao

Hua

et al. 2023

Energy Science & Engineering

Self Cite

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The coal and rock dynamic disasters occur more and more frequently in deep mining, which is tightly correlated to the instability of coal pillars under high stress and cyclic disturbance load. In this study, the strength, deformation behaviors, and failure mechanism of coal under cyclic loading in a high-stress state were investigated by considering the influence of cyclic loading rate. The experimental results indicate that the compressive strength is positively correlated with the cyclic loading rate, and the deformation patterns, AE amplitude, and spatial evolution are the same under various cyclic loading rates. The damage variable shows the "slow increase→fast increase→slow increase→ fast increase →slow increase→fast increase→rapid increase" trend.The damage growth rate ranges from 9.32 × 10 −5 to 4.86 × 10 −3 , and increases with the cyclic loading rate. The spatial fractal dimensions under various cyclic loading rates are the same, and the distribution ranges from 2.1 to 2.9, showing a general downward trend. The microfailure mechanism under various cyclic loading rates is mixed failure dominated by tensile failure, with a small amount of shear failure. There is a positive correlation between the percentage of shear cracks and the cyclic loading rates.

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Influence of bedding planes on fracture characteristics of coal under mode II loading

Cited by 22 publications

References 55 publications

New Method for Determining Mode-I Static Fracture Toughness of Coal Using Particles

New Method for Determining Mode-I Static Fracture Toughness of Coal Using Particles

Study on Fracture Characteristics of Layered Sandstone under Asymmetric Loading

Failure characteristic and acoustic emission spatio‐temporal evolution of coal under different cyclic loading rates

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