Study on the effects of temperature and immersion on the acoustic emission and electromagnetic radiation signals of coal rock damage under load

2021 ◽  
pp. 106503
Author(s):  
Liyang Gao ◽  
Wenrui Zhang ◽  
Wei Lu ◽  
Xiangming Hu ◽  
Hao Wu ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Electromagnetic Radiation ◽  
Rock Damage ◽  
Coal Rock ◽  
Effects Of Temperature

Study on correlation of acoustic emission and plastic strain based on coal-rock damage theory

2017 ◽  
Vol 12 (4) ◽  
pp. 627-637 ◽  
Author(s):  
Peijian Jin ◽  
Enyuan Wang ◽  
Dazhao Song
Keyword(s):  
Acoustic Emission ◽  
Plastic Strain ◽  
Rock Damage ◽  
Coal Rock ◽  
Damage Theory

scholarly journals Size Effect on Acoustic Emission Characteristics of Coal-Rock Damage Evolution

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Zhijie Wen ◽  
Xiao Wang ◽  
Lianjun Chen ◽  
Guan Lin ◽  
Hualei Zhang
Keyword(s):  
Acoustic Emission ◽  
Size Effect ◽  
Damage Evolution ◽  
Effective Means ◽  
Strain Range ◽  
Emission Characteristics ◽  
Peak Strain ◽  
Rock Damage ◽  
Rock Body ◽  
Coal Rock

Coal-gas outburst, rock burst, and other mine dynamic disasters are closely related to the instability and failure of coal-rock. Coal-rock is the assemblies of mineral particles of varying sizes and shapes bonded together by cementing materials. The damage and rupture process of coal-rock is accompanied by acoustic emission (AE), which can be used as an effective means to monitor and predict the instability of coal-rock body. In this manuscript, considering the size effect of coal-rock, the influence of different height to diameter ratio on the acoustic emission characteristics of coal-rock damage evolution was discussed by microparticle flow PFC2D software platform. The results show that coal-rock size influences the uniaxial compressive strength, peak strain, and elastic modulus of itself; the size effect has little effect on the acoustic emission law of coal-rock damage and the effects of the size of coal-rock samples on acoustic emission characteristics are mainly reflected in three aspects: the triggering time of acoustic emission, the strain range of strong acoustic emission, and the intensity of acoustic emission; the damage evolution of coal-rock specimen can be divided into 4 stages: initial damage, stable development, accelerated development, and damage.

scholarly journals Ensemble Learning Approach for the Prediction of Quantitative Rock Damage Using Various Acoustic Emission Parameters

2021 ◽  
Vol 11 (9) ◽  
pp. 4008
Author(s):  
Hang-Lo Lee ◽  
Jin-Seop Kim ◽  
Chang-Ho Hong ◽  
Dong-Keun Cho
Keyword(s):  
Acoustic Emission ◽  
Difficult Problem ◽  
Radioactive Waste Disposal ◽  
Parameter Analysis ◽  
Support Vector ◽  
Uniaxial Compression Test ◽  
Rock Damage ◽  
Initiation Frequency ◽  
Combined Features ◽  
Future Work

Monitoring rock damage subjected to cracks is an important stage in underground spaces such as radioactive waste disposal repository, civil tunnel, and mining industries. Acoustic emission (AE) technique is one of the methods for monitoring rock damage and has been used by many researchers. To increase the accuracy of the evaluation and prediction of rock damage, it is required to consider various AE parameters, but this work is a difficult problem due to the complexity of the relationship between several AE parameters and rock damage. The purpose of this study is to propose a machine learning (ML)-based prediction model of the quantitative rock damage taking into account of combined features between several AE parameters. To achieve the goal, 10 granite samples from KAERI (Korea Atomic Energy Research Institute) in Daejeon were prepared, and a uniaxial compression test was conducted. To construct a model, random forest (RF) was employed and compared with support vector regression (SVR). The result showed that the generalization performance of RF is higher than that of SVRRBF. The R2, RMSE, and MAPE of the RF for testing data are 0.989, 0.032, and 0.014, respectively, which are acceptable results for application in laboratory scale. As a complementary work, parameter analysis was conducted by means of the Shapley additive explanations (SHAP) for model interpretability. It was confirmed that the cumulative absolute energy and initiation frequency were selected as the main parameter in both high and low-level degrees of the damage. This study suggests the possibility of extension to in-situ application, as subsequent research. Additionally, it provides information that the RF algorithm is a suitable technique and which parameters should be considered for predicting the degree of damage. In future work, we will extend the research to the engineering scale and consider the attenuation characteristics of rocks for practical application.

scholarly journals Experimental Research on the Mechanical Characteristics and the Failure Mechanism of Coal-Rock Composite under Uniaxial Load

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Ke Yang ◽  
Zhen Wei ◽  
Xiaolou Chi ◽  
Yonggang Zhang ◽  
Litong Dou ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Acoustic Emission ◽  
Elastic Modulus ◽  
Crack Propagation ◽  
Failure Mechanism ◽  
Poisson’S Ratio ◽  
Mechanical Characteristics ◽  
Poisson's Ratio ◽  
Energy Value ◽  
Coal Rock

Due to the influence of the component structure and combination modes, the mechanical characteristics and failure modes of the coal-rock composite show different characteristics from the monomer. In order to explore the effect of different coal-rock ratios on the deformation and the failure law of the combined sample, the RMT rock mechanics test system and acoustic emission real-time monitoring system are adopted to carry out uniaxial compression tests on coal, sandstone, and three kinds of combined samples. The evolution rules of the mechanical parameters of the combined samples, such as the uniaxial compressive strength, elastic modulus, and Poisson’s ratio, are obtained. The expansion and failure deformation characteristics of the combined sample are analyzed. Furthermore, the evolution laws of the fractal and acoustic emission signals are combined to reveal the crack propagation and failure mechanism of the combined samples. The results show that the compressive strength and elastic modulus of the combined sample increase with the decrease of the coal-rock ratios, and Poisson’s ratio decreases with the decrease of the coal-rock ratios. The strain softening weakens at the postpeak stage, which shows an apparent brittle failure. The combined sample of coal and sandstone has different degrees of damages under load. The coal is first damaged with a high degree of breakage, with obvious tensile failure. The acoustic emission energy value presents different stage characteristics with increasing load. Crackling sound occurs in the destroy section before the sample reaches the peak, along with small coal block ejection and the partial destruction. The energy value fluctuates violently, with the appearance of several peaks. At the postpeak stage, the coal samples expand rapidly with a loud crackling sound in the destroy section, and the energy value increases dramatically. The crack propagation induces the damage in the sandstone; when the energy reaches the limit value, the instantaneous release of elastic energy leads to the overall structural instability.

Study on Acoustic Emission of Rock Damage Based on Physical Cellular Automata

2012 ◽  
Vol 170-173 ◽  
pp. 179-182
Author(s):  
Zhi Tao Ma ◽  
Yong Ping Wang ◽  
Sai Jiang Liang ◽  
Dong Chuan Gao
Keyword(s):  
Nonlinear Dynamics ◽  
Acoustic Emission ◽  
Cellular Automata ◽  
Elastic Energy ◽  
Physical Phenomenon ◽  
New Method ◽  
Rock Deformation ◽  
Dynamics Analysis ◽  
Rock Damage ◽  
Analysis Method

Rock acoustic emission a physical phenomenon during the rock deformation, it is also an effective method used to study the properties of rock damage. In this article, from the aspects of elastic energy, a discrete nonlinear dynamics analysis method was established based on physical cellular automata. Using this new method, the properties of acoustic emission during the rock deformation and damage were studied, and the results were compared with related previous research achievements, and the results show that this new method based on cellular automata is reasonable and effective.

Study on the characteristics of coal rock electromagnetic radiation (EMR) and the main influencing factors

2018 ◽  
Vol 148 ◽  
pp. 216-225 ◽  
Author(s):  
Xiaoyan Song ◽  
Xuelong Li ◽  
Zhonghui Li ◽  
Zhibo Zhang ◽  
Fuqi Cheng ◽  
...  
Keyword(s):  
Electromagnetic Radiation ◽  
Influencing Factors ◽  
Coal Rock

scholarly journals Numerical Study of Rock Fragmentation Process and Acoustic Emission by FDEM Based on Heterogeneous Model

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Qi Liu ◽  
Penghai Deng
Keyword(s):  
Acoustic Emission ◽  
Mechanical Response ◽  
Numerical Study ◽  
High Energy ◽  
Uniaxial Compression Test ◽  
Rock Damage ◽  
Heterogeneous Model ◽  
Damage And Fracture ◽  
Heterogeneous Rock ◽  
Rock Model

Rock has the characteristics of natural heterogeneity and discontinuity. Its failure phenomenon induced by external force involves complex processes, including the microcrack initiation, propagation, coalescence, and the macrocrack formation. In this study, the Weibull random distribution based on the rock microstructure characteristics is introduced into the combined finite-discrete element method (FDEM) to establish the heterogeneous rock model, and the mechanical response and damage evolution of rock samples in uniaxial compression test are simulated. The results show that FDEM simulation with loaded heterogeneous rock model can reflect the progressive development of rock damage, fracture, and acoustic emission (AE) activity in real rock well. Meanwhile, the statistical analysis indicates that the number and energy evolution of AE events with different fracture modes in the model are consistent with the macroscopic failure mode of rock. The change of b-value also agrees with the increasing trend of high-energy events in the loading process. This method provides a new tool for the analysis of rock damage and fracture evolution.

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