Study on vertical cross loading fracture of coal mass through hole based on AE-TF characteristics

Lai, Xingping; Ren, Jie; Cui, Feng; Shan, Pengfei; Dai, Jingjing; Xu, Huicong; Wang, Zeyang

doi:10.1016/j.apacoust.2020.107353

Cited by 18 publications

(5 citation statements)

References 10 publications

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“…Acoustic emission (AE) testing technology is an effective means to study the propagation of defects in brittle materials, such as rocks. At present, this technology is widely used to study the internal damage and fracture behavior of rock materials [19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Uniaxial Experimental Study of the Deformation Behavior and Energy Evolution of Conjugate Jointed Rock Based on AE and DIC Methods

Pan

Guo

et al. 2020

Advances in Civil Engineering

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Conjugate joint is one of the most common joint forms in natural rock mass, which is produced by different tectonic movements. To better understand the preexisting flaws, it is necessary to investigate joint development and its effect on the deformation and strength of the rock. In this study, uniaxial compression tests of granite specimens with different conjugate joints distribution were performed using the GAW-2000 compression-testing machine system. The PCI-2 acoustic emission (AE) testing system was used to monitor the acoustic signal characteristics of the jointed specimens during the entire loading process. At the same time, a 3D digital image correlation (DIC) technique was used to study the evolution of stress field before the peak strength at different loading times. Based on the experimental results, the deformation and strength characteristics, AE parameters, damage evolution processes, and energy accumulation and dissipation properties of the conjugate jointed specimens were analyzed. It is considered that these changes were closely related to the angle between the primary and secondary joints. The results show that the AE counts can be used to characterize the damage and failure of the specimen during uniaxial compression. The local stress field evolution process obtained by the DIC can be used to analyze the crack initiation and propagation in the specimen. As the included angle increases from 0° to 90°, the elastic modulus first decreases and then increases, and the accumulative AE counts of the peak first increase and then decrease, while the peak strength does not change distinctly. The cumulative AE counts of the specimen with an included angle of 45° rise in a ladder-like manner, and the granite retains a certain degree of brittle failure characteristics under the axial loading. The total energy, elastic energy, and dissipation energy of the jointed specimens under uniaxial compression failure were significantly reduced. These findings can be regarded as a reference for future studies on the failure mechanism of granite with conjugate joints.

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Section: Introductionmentioning

confidence: 99%

Uniaxial Experimental Study of the Deformation Behavior and Energy Evolution of Conjugate Jointed Rock Based on AE and DIC Methods

Pan

Guo

et al. 2020

Advances in Civil Engineering

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“…Relevant research conclusions show that when the velocity v of the longitudinal wave decreases by 10%, the damage factor d defined by the acoustic wave is equal to 0.19; that is, the characteristic damage is formed at this moment [25]. The final crack propagation state of the test object is shown in Figure 3.…”

Section: Acquisition Of Test Datamentioning

confidence: 97%

Statistical Characterization of Damage of Different Surface P-Wave Velocity Sets under Dynamic Load and Study on Overall Radon Detection Consistency

et al. 2021

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On the basis of reviewing the existing research status of cumulative damage of the rock mass and summarizing the existing engineering application fields of radon, this paper attempts to apply radon detection technology to the research field of rock damage mechanics so as to monitor the evolution process of cumulative damage of the rock mass. Based on the above research purposes, a test device for detecting cumulative damage of radioactive rocks by surface radon gas was designed, and the test results were obtained by integrating the system to implement the test scheme. Due to the limitation of the nonmetallic ultrasonic detector, a single blasting damage value of 25 detection points appears after a single blasting measurement, which is a surface longitudinal wave velocity characterization damage set, while the surface radon exhalation rate in the subsequent analysis process is an overall characterization value; that is, the existence of damage directly affects the whole body radon exhalation rate of the test block, and the data dimensions of the two are different. In order to solve this problem, we try to introduce three data evaluation methods, the average weighting method, grey prediction method, and K-means clustering algorithm, and compare the feasibility of these three methods. It is proved that there is a certain linear relationship between the radon exhalation rate and the cumulative damage, which further verifies the feasibility of using radon to detect cumulative damage. The results show that the cumulative damage of loaded radioactive rock test blocks can be reflected by surface radon detection technology, and finally, the correlation between the cumulative damage characteristics and the continuous change of the body radon exhalation rate is obtained. Based on the correlation, the body radon exhalation rate is introduced into the field of fractured rock mass damage characterization, which is mutually improved with common monitoring methods such as acoustic emission and microseismic monitoring, supplementing and enriching the means of rock mass damage evolution characterization, providing a theoretical basis for finely describing the whole process of fracture closure and initiation, and finally accurately ensuring the stability of surrounding rock under the action of deep underground engineering excavation disturbance.

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“…e damage stress wave monitored by acoustic emission is a continuous aperiodic waveform induced by the fracture at different times. As shown in Figure 5, any wave function can be decomposed into sinusoidal functions with different amplitude frequencies [28].…”

Section: Analysis Of the Failure Evolutionmentioning

confidence: 99%

Mechanism of Loading Fracture of Coal Mass and Formation of Oil and Gas Disaster Channel in Coal and Oil Resources Costorage Area

Shao

Suo

Yang

2022

Shock and Vibration

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Fracture structure characteristics are crucial for determining the fracture mechanism of coal mass and the migration law of oil and gas disasters. In this study, computed tomography (CT) scanning technology and fractal theory were used to investigate the damage process of coal mass in the common storage area of coal and oil resources under uniaxial compression as well as the degree of damage of high-pressure oil and gas diffusion to the surrounding coal and rock mass. Uniaxial compression and acoustic emission signal acquisition tests of coal mass were conducted. The relationship among the load evolution law of coal samples at different positions around the oil well and the failure mode of key failure positions were further analyzed. Finally, the formation mechanism of coal load fracture and oil and gas disaster channel in coal and oil resource costorage area was investigated. The test results showed the following: (1) High-pressure oil and gas diffusion degrades the mechanical properties of coal mass in varying degrees. The closer the coal sample to the oil well, the greater the fracture development degree, the fracture density, the fracture fractal dimension of coal sample, and the severity of the coal mass damage and the lower the compressive strength, the acoustic emission event number, and the cumulative energy. (2) The lateral diffusion of high-pressure oil and gas changes the failure mode of coal samples in the common storage area of coal and oil resources. The failure modes when the sampling location is away from the oil well are step failure, conjugate shrinkage failure, and high-frequency vibration intermittent microcrack fracture. (3) Coal mass instability and coal mine oil and gas disaster in the common storage area of coal and oil resources can easily be induced by the formation of microfracture expansion, extension, and coalescence caused by coal failure, the formation of network and macrochannels of main fracture, and the instantaneous release of accumulated stress during failure.

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Study on vertical cross loading fracture of coal mass through hole based on AE-TF characteristics

Cited by 18 publications

References 10 publications

Uniaxial Experimental Study of the Deformation Behavior and Energy Evolution of Conjugate Jointed Rock Based on AE and DIC Methods

Uniaxial Experimental Study of the Deformation Behavior and Energy Evolution of Conjugate Jointed Rock Based on AE and DIC Methods

Statistical Characterization of Damage of Different Surface P-Wave Velocity Sets under Dynamic Load and Study on Overall Radon Detection Consistency

Mechanism of Loading Fracture of Coal Mass and Formation of Oil and Gas Disaster Channel in Coal and Oil Resources Costorage Area

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