A Comparative Evaluation of Stress–Strain and Acoustic Emission Methods for Quantitative Damage Assessments of Brittle Rock

Kim, Jin-Seop; Lee, Kyungsoo; Cho, Won-Jin; Choi, Heui-Joo; Cho, Gye-Chun

doi:10.1007/s00603-014-0590-0

Cited by 244 publications

(92 citation statements)

References 34 publications

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“…After the CI threshold, the axial stress at the point where the slope of the "cumulative AE property vs. axial stress" curve further obviously increases can be regarded as the CD threshold. Kim [27] and Zhao [28] proposed that the abrupt slope point of the "cumulative AE property vs. normalized axial stress" curves can be used to determine the above two thresholds. In this work, the methods by Kim and Zhao will be used to determine the CI and CD thresholds of specimens at different inclination angles and freeze-thaw cycles.…”

Section: Determination Methods Of CI and Cd Thresholdsmentioning

confidence: 99%

“…The AE properties mainly include the average AE counts and AE energy. The normalized axial stress can be I II III IV Many studies have shown that AE activity can provide an accurate prediction for the CI and CD thresholds [25][26][27][28]. However, the determination methods of the CI and CD thresholds are different.…”

Section: Effect Of Inclination Angle On CI and Cd Thresholdsmentioning

confidence: 99%

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Experimental Study on Physical-mechanical Properties and Fracture Behaviors of Saturated Yellow Sandstone Considering Coupling Effect of Freeze-Thaw and Specimen Inclination

Chen

et al. 2020

Sustainability

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The effect of freeze-thaw on the physical-mechanical properties and fracture behavior of rock under combined compression and shear loading was crucial for revealing the instability mechanism and optimizing the structure design of rock engineering in cold regions. However, there were few reports on the failure behavior of rock treated by freeze-thaw under combined compression and shear loading due to the lack of test equipment. In this work, a novel combined compression and shear test (C-CAST) system was introduced to carry out a series of uniaxial compression tests on saturated yellow sandstone under various inclination angles (θ = 0°, 5°, 10°, and 15°) and the number of freeze-thaw cycles (N = 0, 20, 40, and 60). The test results showed that the P-wave velocity dramatically decreased, while the rock quality and porosity increased gradually as N increased; the peak compression strength and elastic modulus obviously decreased with the increasing θ and N, while the peak shear stress increased gradually with the increasing θ and decreased with the increase of N, indicating that the shear stress component can accelerate the crack propagation and reduce its resistance to deformation. The acoustic emission (AE) results revealed that the change of crack initiation (CI) stress and crack damage (CD) stress with the θ and N had a similar trend as that of the peak compression strength and elastic modulus. Particularly, the CI and CD thresholds at 60 cycles were only 81.31% and 84.47% of that at 0° cycle and indicated a serious freeze-thaw damage phenomenon, which was consistent with the results of scanning electron microscopy (SEM) with the appearance of some large-size damage cracks. The fracture mode of sandstone was dependent on the inclination angle. The failure mode developed from both the tensile mode (0°) and combined tensile-shear mode (5°) to a pure shear failure (10°–15°) with the increasing inclination angle. Meanwhile, the freeze-thaw cycle only had an obvious effect on the failure mode of the specimen at a 5° inclination. Finally, a novel multivariate regression analysis method was used to predict the peak compression strength and elastic modulus based on the initial strength parameters (θ = 0°, N = 0). The study results can provide an important reference for the engineering design of rock subjected to a complex stress environment in cold regions.

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Section: Determination Methods Of CI and Cd Thresholdsmentioning

confidence: 99%

Section: Effect Of Inclination Angle On CI and Cd Thresholdsmentioning

confidence: 99%

Experimental Study on Physical-mechanical Properties and Fracture Behaviors of Saturated Yellow Sandstone Considering Coupling Effect of Freeze-Thaw and Specimen Inclination

Chen

et al. 2020

Sustainability

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“…Acoustic emission events are fewer before yield and gradually become more active during the period of postyield, and then the AE cumulative count and the cumulative number of energy have the singular points obviously in the case of the stress peak [8,9]. The characteristics of AE are analyzed under the unloading confining pressure, and then the failure characteristics and the mechanism of rock burst 2 Shock and Vibration are discussed with the granite unloading confining pressure test on acoustic emission under different loading paths [7,[10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Mechanical and Acoustic Emission Characteristics of Rock Samples under Different Stress Paths

Qin

Sun

Liu

et al. 2018

Shock and Vibration

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A series of tests on characteristics of acoustic emission have been performed on sandstone under uniaxial, conventional, and triaxial conditions and the unloading confining pressure path. The failure mode of rock specimen has been scanned by CT and a threedimensional reconstruction was made. The differences on characteristics of AE, mechanics, and the failure mode of sandstone during the failure process under three paths are studied. The results show that the deformation of rock specimen is bigger, and axial strain and circumferential strain have a deformation platform at peak point of stress under the unloading confining pressure path. Characteristics of AE ringing are significantly affected by the confining pressure and stress path. AE ringing counts peak value, and accumulative ringing on the breaking moment as well as cumulative release energy is higher, which indicates that the rock failure is more violent under the unloading confining pressure path. The failure mode of rock specimen was dominated by shear failure under the conventional triaxial stress path. The tension failure is the main form at a lower initial value of unloading confining pressure, and the shear failure is more prominent at a higher initial value of unloading confining pressure.

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“…They concluded that the normalized crack damage lateral strain and the volumetric strain quantities were strongly affected by the grain size. Kim, Lee, Cho, Choi, & Cho (2014) identified the crack initiation and damage stress thresholds of granite using AE activity. They concluded that the crack initiation threshold was found at a stress level of 0.42 -0.53 σ c , and the crack damage threshold was identified at 0.62 -0.84 σ c .…”

Section: Literature Reviewmentioning

confidence: 99%

Strength and strain quantities under brittle compression process of hard rocks

Akinbinu¹,

Oniyide²,

Adesida³

2018

Min. miner. depos.

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Purpose. To examine the relationships between strength properties and strain quantities associated with the brittle compression process of hard brittle rocks.Methods. The data used in this paper were obtained from laboratory uniaxial compression tests carried out on 84 different types of hard rocks in accordance with Ulusay (2015) proposed standards. The strength properties and the strain quantities were coordinated so that each of the strain quantities or their ratios is compared individually with the strength properties of the rocks as for their relationship.Findings. In all the cases the relationships between the strain ratios and the strength parameters are stronger than when compared with individual strain quantities. A threshold level for strain ratio Ɛ vf / Ɛ cd may be assumed as the limit for fracture initiation above which the rock may experience brittle fracture failure.Originality. Scientific sources demonstrate few laboratory studies as for strength properties-strain quantities ratio. Most of the published research has been concentrated on crack damage stress (σ cd ) and uniaxial compressive strength (σ c ) of characteristic stress levels during compression. The paper has performed detailed analysis of the problem using experimental results of the relationships between strength properties and strain quantities under the deformation process of hard rocks. Practical implications.The relationships can improve our knowledge to evaluate correctly the stability of excavations, design of stable structures such as tunnels and excavations for mining and civil engineering purposes.

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A Comparative Evaluation of Stress–Strain and Acoustic Emission Methods for Quantitative Damage Assessments of Brittle Rock

Cited by 244 publications

References 34 publications

Experimental Study on Physical-mechanical Properties and Fracture Behaviors of Saturated Yellow Sandstone Considering Coupling Effect of Freeze-Thaw and Specimen Inclination

Experimental Study on Physical-mechanical Properties and Fracture Behaviors of Saturated Yellow Sandstone Considering Coupling Effect of Freeze-Thaw and Specimen Inclination

Experimental Study on Mechanical and Acoustic Emission Characteristics of Rock Samples under Different Stress Paths

Strength and strain quantities under brittle compression process of hard rocks

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