Journal ArticleDOI
Study on Spectrum Characteristics and Clustering of Acoustic Emission Signals from Rock Fracture
TLDR
In this paper, acoustic emission waveform signals during rock loading are acquired through uniaxial compression test of granite in laboratory and digital image correlation technology is used, showing the usefulness of the DIC and acoustic emission techniques in experiment of that type.Abstract:
Acoustic emission signals are relevant to the process of rock failure. In this paper, acoustic emission waveform signals during rock loading are acquired through uniaxial compression test of granite in laboratory. Short-time Fourier transform is used to analyze the acoustic emission signals during rock fracture to obtain the peak frequency. Based on the peak frequency of acoustic emission, four types of acoustic emission signals are classified by using fuzzy C-means method. The parameters of different types of acoustic emission signals are analyzed, which include ring count, duration, amplitude and energy. Meanwhile, the progressive propagation of surface cracks in rock specimens is quantitatively analyzed by digital image correlation (DIC) technology. The result shows that different types of acoustic emission signals correspond to different strength of rock fracture. Before rock fracture, high-count, long-duration and high-energy precursory characteristic signals appear intensively. The event density $$ {\text{Den}}_{t} = 1 $$ is taken as the early warning threshold of rock fracture through the quantitative analysis of acoustic emission signal. The present results of the research show the usefulness of the DIC and acoustic emission techniques in experiment of that type.read more
Citations
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Journal ArticleDOI
Experimental investigation on synergetic prediction of rockburst using the dominant-frequency entropy of acoustic emission
TL;DR: In this article, the information entropy of the dominant frequency was determined to be an indicator of rockburst, and a multiparameter synergetic method was proposed based on the comprehensive analysis of AE energy, dominant-frequency entropy, and other precursory information of rock failure.
Journal ArticleDOI
Extracting acoustic emission features that precede hard rock instability with unsupervised learning
TL;DR: In this article , acoustic emission (AE) signals were acquired, and their clustering features were automatically extracted by the clustering unsupervised learning method, which showed that a class of AE signals featured high rise time, high ring count, high energy and low peak frequency and low quantity can be used as an indicative precursor feature of hard rock instability.
Journal ArticleDOI
Application of Wavelet Transform in Evaluating the Kaiser Effect of Rocks in Acoustic Emission Test
TL;DR: In this paper , a continuous wavelet transform analysis was performed on Phyllite samples and acoustic data was recorded simultaneously, where an energy-based and count-based parametric approach was used to estimate the occurrence time of the Kaiser effect.
Journal ArticleDOI
Time–Frequency Domain Characteristics of Acoustic Emission Signals and Critical Fracture Precursor Signals in the Deep Granite Deformation Process
TL;DR: In this article, the authors used a TAW-2000 triaxial hydraulic servo testing machine and a PCI-II acoustic emission monitoring system to study the crack evolution and failure precursory characteristics of deep granite rocks under high confining pressure.
Journal ArticleDOI
Analysis the Characteristic of Energy and Damage of Coal-Rock Composite Structure Under Cycle Loading
TL;DR: In this paper, a more sensitive joint calculation method for calculating damage variables was proposed based on the difference of damage variables calculated by dissipated energy method and acoustic emission method, which can more accurately and sensitively reflect the damage of coal-rock composite structure under cyclic loading.
References
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Journal ArticleDOI
Identifying crack initiation and propagation thresholds in brittle rock
TL;DR: In this article, it was shown that high compressive stresses near the tunnel face significantly contribute to the tunnel tunnel collapse and that the tunnel's tunnel face can be damaged due to the compressive stress.
Journal ArticleDOI
Quantifying progressive pre-peak brittle fracture damage in rock during uniaxial compression
TL;DR: In this article, a rigorous methodology has been developed to aid in the identification and characterization of brittle fracture processes induced through uniaxial compressive loading, which can be easily quantified by normalizing the stresses and strains observed in progression from one stage of crack development to another.
Journal ArticleDOI
Fracture initiation and propagation in intact rock – A review
Evert Hoek,C.D. Martin +1 more
TL;DR: The Griffith theory of brittle failure provides a simplified model and a useful basis for discussion of this process as mentioned in this paper, and the Hoek-Brown failure criterion provides an acceptable estimate of the peak strength for shear failure but a cutoff has been added for tensile conditions.
Journal ArticleDOI
Hoek-Brown parameters for predicting the depth of brittle failure around tunnels
TL;DR: A review of underground openings, excavated in varying rock masstypes and conditions, indicates that the initiation of brittle failure occurs when the damage index, Di, expressed as the ratio of the...
Journal Article
Criteria for strength and structural failure of rocks based on energy dissipation and energy release principles
TL;DR: In this paper, the intrinsic relations between energy dissipation, energy release, and strength and abrupt structural failure of rocks during failure process are discussed, and the critical stresses at the time of abrupt structural failures of rock under various stress states can be determined by these principles.