Moment tensor analysis of acoustic emission for cracking mechanisms in rock with a pre-cut circular hole under uniaxial compression

Liu, Jianpo; Li, Yuanhui; Xu, Shugen; Xu, Shuai; Jin, Changyu; Zhao-sheng, Liu

doi:10.1016/j.engfracmech.2015.01.006

Cited by 108 publications

(24 citation statements)

References 22 publications

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“…Hampton et al [28] categorized AE into shear, tensile, and mixed mode, through manipulating the eigenvalues of the moment tensor matrix. This method has been widely used to identify rock failure under different stress conditions [29][30][31]. Actually, this method was first proposed for an in situ hydrofracturing test [32].…”

Section: Introductionmentioning

confidence: 99%

Micro-Crack Mechanism in the Fracture Evolution of Saturated Granite and Enlightenment to the Precursors of Instability

Dong

Zhang

2020

Sensors

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To explore the potential precursors of rock instability, it is necessary to clarify the mechanism of micro-crack from fracturing to failure, which involves the evolution of fracture size, orientation, source model, and their relationships to the loading. The waveforms of acoustic emission (AE) recorded by the sensor network attached rock sample during laboratory tests provide a data basis for solving these problems, since these observations are directly related to the characteristics of the fracturing sources. Firstly, we investigated the source mechanism, looking at the rise angle and the average frequency (RA-AF) trends during five loading stages in a uniaxial compression test. Results show that the proportion of shear events significantly increases when approaching instability. Secondly, we calculated the moment tensor for each event, considering the uncertainties of P-wave polarity, azimuth, and the takeoff angles of the rays. Moment tensor solutions suggest that there are obviously more crack events than shear events in all loading stages. Moment tensor evolutions confirmed that the decreasing of isotropic component and the increment of double-couple can be used as precursors of rock fracturing development. Considering the limitations of these two methods, it is suggested that we should be concerned more about the proportions of individual failure components and their evolutions over time, instead of absolutely classifying the events into a certain source type.

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Section: Introductionmentioning

confidence: 99%

Micro-Crack Mechanism in the Fracture Evolution of Saturated Granite and Enlightenment to the Precursors of Instability

Dong

Zhang

2020

Sensors

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“…Seismic moment tensor, the theoretical framework of seismic source based on generalized force couples [10]- [15], increases our understanding of induced seismicity by providing information about the rupture process, the local stress field, as well as the relationship between mining operations, stress redistributions and the instability of the rockmass [16]- [19]. It is a general term and can be compared to various source models, such as a displacement on a fault, an implosive failure, a sudden volume increases due to explosion, even mixed mechanisms driven by stress concentration [20]. The general and flexible concept makes moment tensor inversion an important tool in seismic source characterization.…”

Section: ) Enables Detecting and Locatingmentioning

confidence: 99%

Investigating Factors Influencing Moment Tensor Inversion of Induced Seismicity in Virtual IoT

Wang

Han

et al. 2019

IEEE Access

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The Internet of Things (IoT) for seismicity in underground mine consists of a combination of sensor network hardware and software, which allows the collection of seismic data and data processing for basic event parameters. A seismic moment tensor is one of the essential parameters in evaluating the seismic hazard. The reliability of the resolved seismic moment tensor depends on numerous factors, and it is important to understand the influence of these disturbances. We focused on influencing factors, including the azimuthal coverage, the accuracy of source coordinate, the mismodeling of velocity structure, and the noise contamination. A set of moment tensor inversions using synthetic data simulated for a double couple source and a superimposed source from virtual IoT was carried out to test the effects of different factors. We concluded that the sensitivity of the moment tensor inversion to the azimuthal coverage is closely related to the type of the source. For the shear event, the inversion does not require a good azimuthal coverage, but for the non-pure shear event, at least 90 • azimuthal coverage is required to get the reliable solution. The full moment tensor is not sensitive to the location accuracy when the source error is less than 60 m, regardless of the type of source. But the double couple deviation increases with the growing error of the location, especially for the fault-slip-related or the shear rupture-dominated event. The erroneous velocity models show nearly no influence on the full moment tensor inversion results. The fit of amplitude spectra does not require a precise alignment of the observed and the synthetic waveforms and is less dependent on the chosen velocity model. The superimposed source is more sensitive to noise than the pure shear source. Although the noise does not necessarily affect the fault plane solution of the event, it is capable to lead an inaccurate seismic moment tensor and mislead the interpretation of the source type. INDEX TERMS Moment tensor inversion, synthetic tests, source model, IoT for seismicity.

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“…For each value of k (k ¼ 1, 2, … , 4096), the AR model for the k and nÀk data was established, and the AIC was adopted to estimate the rationality of the models. The criterion C ap is expressed as follows (Katsuyama 1996;Liu et al 2015):…”

Section: Determination Of the First Motion Amplitude Of The P-wavementioning

confidence: 99%

Source analysis of acoustic emissions during granite strain burst

Wang

He²,

Ren

et al. 2019

Geomatics, Natural Hazards and Risk

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The acoustic emission (AE) location technique and fault-plane solution method were used to evaluate the temporal-spatial evolution, released energy variation of micro-cracks, and the difference in b-values for different types of micro-cracks during granite strain burst tests. Results show that AE locations coincide with the macroscopic cracks in the ejection zone. AE locations are scattered for the fracture zone after unloading. The fragment ejection was the results of the combined action of shear, tensile, and compressional micro-cracks; furthermore, the released energy from compressional micro-cracks was largest at the moment of strain burst. Additionally, compressional micro-cracks were the most common, and the tensile micro-cracks were the lease common. For compressional micro-cracks, the overall trend of the b-values was downward, while b-values for shear and tensile micro-cracks both increased. For the fracture zones, the b-value of the microcracks was decreased firstly and then increased, while b-values for the ejection zones decreased firstly and then fluctuated and increased.

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Moment tensor analysis of acoustic emission for cracking mechanisms in rock with a pre-cut circular hole under uniaxial compression

Cited by 108 publications

References 22 publications

Micro-Crack Mechanism in the Fracture Evolution of Saturated Granite and Enlightenment to the Precursors of Instability

Micro-Crack Mechanism in the Fracture Evolution of Saturated Granite and Enlightenment to the Precursors of Instability

Investigating Factors Influencing Moment Tensor Inversion of Induced Seismicity in Virtual IoT

Source analysis of acoustic emissions during granite strain burst

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