Acoustic emission monitoring technology for coal and gas outburst

Li, Jiangong; Hu, Qianting; Yu, Minggao; Li, Xuelong; Hu, Jie; Yang, Hengquan

doi:10.1002/ese3.289

Cited by 36 publications

(13 citation statements)

References 40 publications

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“…With further unloading, large numbers of cracks can be observed around the excavation boundaries. The strain rockburst is triggered once the accumulated strain energy exceeds the surface energy required for rock fracturing . Because of the unwanted corners, the cubic hole will cause severe roof caving and floor heaving and even intense dynamic hazards.…”

Section: Resultsmentioning

confidence: 99%

Analysis of fractures of a hard rock specimen via unloading of central hole with different sectional shapes

Fan

Chen

et al. 2019

Energy Science & Engineering

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Hard rock failure and rockburst hazards under high in situ stresses have been the subject of deep rock mechanics and engineering. Previous investigations employed cubic rock specimens with a central hole for simulation of rock fracturing around deep tunnels at a laboratory scale, while the failure characteristics and crack evolution behavior around different shapes of holes induced by excavation unloading response have been barely considered. A commercially combined finite‐discrete element method (combined FEM/DEM) was used to investigate the failure characteristics and crack propagation process of typical hard rock specimens (marble) via the unloading of central hole with different shapes. Rock heterogeneity was also considered in the model in combination with the engineering reality. The combined FEM/DEM approach was first validated by simulating uniaxial compression and Brazilian tests. Then, the parametrical analysis was conducted in detail on the basis of five different sectional shapes of central holes, including a circle, ellipse, U‐shape, trapezoid, and cube, and two lateral pressure coefficients. Analysis of crack propagation paths, released strain energy, displacement, and average velocity distribution of the monitoring points around the central hole suggests that the failure degree and destruction intensity are strongly related to the sectional shape and lateral pressure coefficients. Hard and brittle rock failure induced by the excavation unloading effect can be classified as stable failure (slabbing failure) and unstable failure (strain rockburst). The cubic, trapezoidal, and U‐shaped holes within the specimen are the most likely to induce unstable failure, while stable failure is the dominant failure pattern around circular and elliptical holes. The lateral pressure coefficient λ was also found to affect failure position and intensity (only for the axisymmetric section) around the central hole. The influence of rock heterogeneity on failure intensity and range around the central hole within the specimen was also discussed. This study emphasizes the importance and necessity of the excavation unloading effect when evaluating surrounding rock failure around deep tunnels.

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Section: Resultsmentioning

confidence: 99%

Analysis of fractures of a hard rock specimen via unloading of central hole with different sectional shapes

Fan

Chen

et al. 2019

Energy Science & Engineering

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“…They found that mining depth is the most significant factor among all factors, and distance from fault is the most significant contributing factor to outburst. Li et al [11] investigated the acoustic emissions (AE) characteristics of coal and rock samples under loading and monitored and predicted the coal and gas outburst dynamic disasters at the working face using self-developed AE continuous monitoring and early warning equipment. It was found that coal and gas outbursts occurred in stress post-peak zone.…”

Section: Of 13mentioning

confidence: 99%

Expansionary Evolution Characteristics of Plastic Zone in Rock and Coal Mass Ahead of Excavation Face and the Mechanism of Coal and Gas Outburst

2020

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Factors leading to coal and gas outbursts are complicated, and the accuracy of predicting outbursts remains difficult to achieve. Therefore, coal and gas outburst risk are still a scientific challenge in the fields of mining, geology, safe engineering, and rock mechanics. Theories explaining and predicting coal and gas outbursts associated with restored strain and gas energy are hot topics. Based on numerical modelling, the evolution of a plastic zone ahead of an excavation face with change of direction and magnitude of regional pre-mining stress field were analyzed. A mechanical analysis model for the expansionary evolution process of the plastic zone ahead of the excavation face was constructed, and the expansionary evolution characteristics of plastic zone ahead of the excavation face were analyzed. The physical and mechanical process and basic conditions for the initiation and development of coal and gas outbursts induced by evolution of plastic zone were discussed. The research provides some new insights into the mechanism, prediction, and prevention of goal and gas outbursts.

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“…This traditional coal and gas outburst prediction is an empirical sampling‐based, discontinuous, and localized prediction method, which cannot fully meet the needs of high‐yield, high‐efficiency mine safety production. The noncontact dynamic prediction method is the method for assessing outburst risk by monitoring the physical properties of sound, electricity, magnetism, and thermal and gas emission in the initiation process of coal and gas outburst, including the AE acoustic emission signal, electric radiation detection, gas emission, and microseismic monitoring methods . These methods are dynamic and continuous in time and space, and only require minimal work.…”

Section: Introductionmentioning

confidence: 99%

Applications of online integrated system for coal and gas outburst prediction: A case study of Xinjing Mine in Shanxi, China

Zhao

Sun

Cao

et al. 2020

Energy Science & Engineering

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In this study, an indicator model and system for coal and gas outburst prediction are identified and established based on gas geological anomalies, mining stress, and gas emission characteristics. In this regard, the coal and gas outburst prevention techniques and mine rules in China are taken into account. In addition, using this model, an online integrated system and database for coal and gas outburst prediction were built for Xinjing Mine in Shanxi Province. The application results of the prediction system indicate that the system software and hardware can guarantee early warning of coal and gas outburst. The system is continuous and stable, and the early warning results are issued in a timely and accurate manner. The accuracy of the early warning results is high and consistent with the actual risk of the mine. K E Y W O R D Scase study, coal and gas outburst, coal mine, multisource information, prediction | 1981 ZHAO et Al.

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Acoustic emission monitoring technology for coal and gas outburst

Cited by 36 publications

References 40 publications

Analysis of fractures of a hard rock specimen via unloading of central hole with different sectional shapes

Analysis of fractures of a hard rock specimen via unloading of central hole with different sectional shapes

Expansionary Evolution Characteristics of Plastic Zone in Rock and Coal Mass Ahead of Excavation Face and the Mechanism of Coal and Gas Outburst

Applications of online integrated system for coal and gas outburst prediction: A case study of Xinjing Mine in Shanxi, China

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