Microcracking in tensile fracture of a brittle rock

Wang, Xiaoran; Asem, Pouyan; Hu, Chen; Labuz, Joseph F.

doi:10.1016/j.engfracmech.2021.107789

Cited by 37 publications

(10 citation statements)

References 28 publications

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“…However, when the axial loading and control system is activated at this threshold, the AE signal can be monitored. As a result of many tests, 45 dB was selected as the threshold in these experiments [12,66]. To measure acoustic emission signals, the acoustic emission monitor, amplifier, and sensor are connected in sequence.…”

Section: Experimental Setup and Proceduresmentioning

confidence: 99%

Analytical Damage Model for Predicting Coal Failure Stresses by Utilizing Acoustic Emission

Ali

Wang

et al. 2023

Sustainability

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Overburden collapse and water inrush in mines are primarily caused by rock fractures. Mining safety can be enhanced by monitoring and identifying early signs of coal failure in the mines. This article collected acoustic emission data synchronously throughout a series of uniaxial compression (UC) experiments on natural and water-saturated coal. The influence mechanisms of water, mechanical properties, and acoustic emission signals on the stress–strain curve and the SEM results of water-saturated and dry samples are investigated. As a result, the mechanical properties of coal are not only weakened by water saturation, such as elastic modulus, strain, stress, and compressive strength but also reduced acoustic emissions. In comparison with saturated coal, natural coal has a uniaxial stress of 13.55 MPa and an elastic modulus of 1.245 GPa, while saturated coal has a stress of 8.21 MPa and an elastic modulus of 0.813 GPa. Intergranular fractures are more likely to occur in coal with a high water content, whereas transgranular fractures are less likely to occur in coal with a high water content. An innovative and unique statistical model of coal damage under uniaxial loading has been developed by analyzing the acoustic emission data. Since this technique takes into account the compaction stage, models based on this technique were found to be superior to those based on lognormal or Weibull distributions. A correlation coefficient of greater than 0.956 exists between the piecewise constitutive model and the experimental curve. Statistical damage constitutive models for coal are compatible with this model. Additionally, the model can precisely forecast the stress associated with both natural and saturated coal and can be useful in the prevention of rock-coal disasters in water conditions.

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Section: Experimental Setup and Proceduresmentioning

confidence: 99%

Analytical Damage Model for Predicting Coal Failure Stresses by Utilizing Acoustic Emission

Ali

Wang

et al. 2023

Sustainability

Self Cite

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“…More recently, the waveform characteristics of AE signals have been extensively studied in laboratory tests, including spectrum characterization [22][23][24] and source inversion. [25][26][27] Bhuiyan et al 22 explored the microcrack fracture mechanism of aerospace materials by analyzing the spectrum features of AE waveforms. The results show that the evolution of waveform spectrums was closely related to the boundary conditions and crack propagation.…”

Section: Introductionmentioning

confidence: 99%

“…It is known that nonlinear waveform signals are generated by the irreversible deformation of rock materials, which contains much microcracks information of rock failure. More recently, the waveform characteristics of AE signals have been extensively studied in laboratory tests, including spectrum characterization 22–24 and source inversion 25–27 . Bhuiyan et al 22 explored the microcrack fracture mechanism of aerospace materials by analyzing the spectrum features of AE waveforms.…”

Section: Introductionmentioning

confidence: 99%

“…The results show that it not only obtained the temporal–spatial evolution of tensile and shear microcracks but also revealed the failure mechanism of tensile and tensile‐shear mixed cracks. Likewise, Wang et al 27 proposed a point source‐based moment tensor modeling to distinguish the crack types, spatial position, and propagation direction of microcracks and further revealed the time sequence response features. Summarizing the above review, it is found that the current inversion models are based on the homogeneous assumption while ignoring the heterogeneity of engineering practice, and the results cannot meet the accuracy requirements.…”

Section: Introductionmentioning

confidence: 99%

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Temporal‐frequency distribution and multi‐fractal characterization of acoustic emission of rock materials containing two parallel pre‐existing flaws

Lei

Tan

Berto

et al. 2023

Fatigue Fract Eng Mat Struct

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To explore the temporal‐frequency distribution and multi‐fractal characterization of acoustic emission (AE) signals, a series of uniaxial compressive tests on flawed sandstone containing different flaw geometric arrangements were conducted. The results show that there are primarily low‐frequency and low‐amplitude signals at relatively low stress levels. With the increase of stress level, the components of high‐frequency and high‐amplitude signals increase remarkably. Spectrum width (∆α) follows an approximate trend of first decreasing and then increasing with increasing stress levels. When the stress level increases to 0.8σc, spectrum morphology (∆α0) changes from a positive value to a negative value, indicating that the failure mechanism in rock transforms from microcrack damage to large‐scale shear rupture. Additionally, spectrum measure subset (∆f) and ∆α0 present an opposite trend. With regard to the flawed sandstone, the fracture mechanism is predominately dominated by the microscopic tensile cracks, whereas the microscopic shear cracks in intact sandstone account for a large proportion.

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“…The physical and mechanical properties of frozen rock, including explosiveness and drillability, need to be considered in the mining and blasting of frozen rock. The existence of joints in underground frozen rock in alpine regions also makes the interaction between explosives and rock extremely complex, changes the failure mode of rock and has a great impact on the blasting effect [5][6][7]. In a word, the multi-joint and high-freezing properties of underground frozen rock bring many difficulties to blast mining.…”

Section: Introductionmentioning

confidence: 99%

Study on Blasting Effect Optimization to Promote Sustainable Mining under Frozen Conditions

Cheng

et al. 2022

Sustainability

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In order to respond to the theme of national green and healthy sustainable development and in response to the problems of large block rates and pollution of the environment after the blast mining of underground rocks in alpine areas, we conducted research on the joints of underground rocks and the blastability of frozen rocks. According to the actual geological conditions of an underground mine blasting in Heilongjiang Province, three kinds of joint blasting geometric models were established. The rock mass blasting process of different types of joints was simulated by LS-DYNA software and the influence law of joints on rock mass blasting was summarized. The blasting crater test and the triaxial compression test of frozen rock were carried out. Combined with the blasting fragmentation characterization function (R-R and G-G-S), the blasting fragmentation, strength and stiffness of frozen rock at different temperatures were obtained. Based on the above, the blasting parameters of a multi-joint underground rock mass in an alpine region were optimized: hole spacing 4.0 m, row spacing 2.5 m, hole depth 11.5 m, V-type initiation network. The optimized blasting parameters significantly improved the mining efficiency and reduced the large lump rate to 3.1%. In order to promote the sustainable exploitation of resources in alpine regions, this study optimized the blasting technology of underground rock mass.

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Microcracking in tensile fracture of a brittle rock

Cited by 37 publications

References 28 publications

Analytical Damage Model for Predicting Coal Failure Stresses by Utilizing Acoustic Emission

Analytical Damage Model for Predicting Coal Failure Stresses by Utilizing Acoustic Emission

Temporal‐frequency distribution and multi‐fractal characterization of acoustic emission of rock materials containing two parallel pre‐existing flaws

Study on Blasting Effect Optimization to Promote Sustainable Mining under Frozen Conditions

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