Role of the rapid gas desorption of coal powders in the development stage of outbursts

Zhao, Wei; Wang, Chenghao; Jiang, Haina; Jin, Kan; Wang, Haifeng; Wang, Liang

doi:10.1016/j.jngse.2015.12.025

Cited by 160 publications

(67 citation statements)

References 33 publications

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“…However, few of the proposed mechanisms can be successfully applied to explain, predict, and prevent outbursts. Due to the unique characteristics of these destructive, short duration, and high‐intensity events, outbursts are both unpredictable in space and time . It remains difficult to accurately measure in situ stress and gas pressure or to examine coal properties at different scales and for varied impact loads .…”

Section: Introductionmentioning

confidence: 99%

“…Due to the unique characteristics of these destructive, short duration, and high-intensity events, outbursts are both unpredictable in space and time. 5,6,19,20 It remains difficult to accurately measure in situ stress and gas pressure or to examine coal properties at different scales and for varied impact loads. 21 Current wisdom is that outbursts are a violent dynamic instability of the coal mass when the interaction of abnormal geostresses, high gas pressures, and the presence of "outburst-prone" coal reaches a critical condition.…”

Section: Introductionmentioning

confidence: 99%

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Experimental investigation on dynamic strength and energy dissipation characteristics of gas outburst‐prone coal

Fan

Elsworth

et al. 2019

Energy Science & Engineering

113

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We report laboratory experiments to investigate the dynamic failure characteristics of outburst‐prone coal using a split Hopkinson pressure bar (SHPB). For comparison, two groups of experiments are completed on contrasting coals—the first outburst‐prone and the second outburst‐resistant. The dynamic mechanical properties, failure processes, and energy dissipation of both outburst‐prone and outburst‐resistant coals are comparatively analyzed according to the obtained dynamic compressive and tensile stress‐strain curves. Results show that the dynamic stress‐strain response of both outburst‐prone and outburst‐resistant coal specimens comprises stages of compression, linear elastic deformation, then microfracture evolution, followed by unstable fracture propagation culminating in rapid unloading. The mechanical properties of both outburst‐prone and outburst‐resistant coal specimens exhibit similar features: The uniaxial compressive strength and indirect tensile strength increase linearly with the applied strain rate, and the peak strain increases nonlinearly with the strain rate, whereas the elastic modulus does not exhibit any clear strain rate dependency. Differences in the dynamic failure characteristics between outburst‐prone and outburst‐resistant coals also exist. The hardening effect of strain rate on outburst‐prone coal is more apparent than on outburst‐resistant coal, which is reflected in the dynamic increase factor at the same strain rate. However, the dynamic strength of outburst‐prone coals is still lower than that of outburst‐resistant coals due to its low quasi‐static strength. The dissipated energy of outburst‐prone coal is smaller than that of outburst‐resistant coal. Therefore, the outburst‐prone coal, characterized by low strength, high deformability, and small energy dissipation when dynamically loaded to failure, is more favorably disposed to the triggering and propagation of gas outbursts.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental investigation on dynamic strength and energy dissipation characteristics of gas outburst‐prone coal

Fan

Elsworth

et al. 2019

Energy Science & Engineering

113

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“…Furthermore, it has been proved that the high pressure gradient produced by a large volume of gas desorbed within a short period is an essential condition to push the crushed coal into the mining space. 1,[3][4][5][6] According to the theory of the comprehensive effect of coal, gas, and crustal stress, the gas pressure is the power source of coal and gas outburst, and the adsorption and desorption characteristics of coal partly determine the gas occurrence and gas pressure, which affect the probability and | 975 WANG et Al. level of the coal and gas outburst accidents.…”

Section: Introductionmentioning

confidence: 99%

Correlation between coal and gas outburst risk and adsorption properties of coal seams

Wang

Zou

2019

Energy Science & Engineering

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Based on the Langmuir adsorption model, the adsorption constants of eighteen coal samples from the same coal mine with outburst risk, weak outburst risk, and non‐outburst risk were tested by high‐pressure capacity method under different temperature conditions. The results show that the adsorption constants a and b monotonically decrease with the increase in temperature. The relationship between a and temperature shows three stages: accelerated decreasing stage, decelerated decreasing stage, and stable stage. The b decreases with the increase in temperature also shows three stages, namely relative stability, slow decrease, and accelerated decrease. The a × b for the outburst coal seam decreases with increasing temperature, which is similar to b. The a × b for the weak and non‐outburst coal seams decreases with increasing temperature, which is similar to a. Furthermore, the a of the outburst coal seam decreases with the increase in temperature, and the decrease of b is the largest. The a of the weak and non‐outburst coal seams decreases with the increase in temperature, and the magnitude is relatively large. The b decreases slightly, with a smaller magnitude. The a × b of weak outburst seam is smaller than that of non‐outburst seam and is larger than that of outburst seam. The achievements can provide guiding significance for coal and gas outburst prevention and control.

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“…Peng et al used outburst test equipment to analyze the influence of permeability and non-uniform loading, gas pressure and moisture content [15][16][17]. In the recent two years, scholars such as Tu [18], Zhao [19] and Xu [20] studied the effects of gas enrichment and adsorption on the outburst by simulation tests. Therefore, to a certain extent, they promoted the understanding of coal and gas outburst mechanism.…”

Section: Introductionmentioning

confidence: 99%

Experimental Research on the Impactive Dynamic Effect of Gas-Pulverized Coal of Coal and Gas Outburst

Sun

Cao

et al. 2018

Energies

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Coal and gas outburst is one of the major serious natural disasters during underground coal, and the shock air flow produced by outburst has a huge threat on the mine safety. In order to study the two-phase flow of a mixture of pulverized coal and gas of a mixture of pulverized coal and gas migration properties and its shock effect during the process of coal and gas outburst, the coal samples of the outburst coal seam in Yuyang Coal Mine, Chongqing, China were selected as the experimental subjects. By using the self-developed coal and gas outburst simulation test device, we simulated the law of two-phase flow of a mixture of pulverized coal and gas in the roadway network where outburst happened. The results showed that the air in the roadway around the outburst port is disturbed by the shock wave, where the pressure and temperature are abruptly changed. For the initial gas pressure of 0.35 MPa, the air pressure in different locations of the roadway fluctuated and eventually remain stable, and the overpressure of the outburst shock wave was about 20~35 kPa. The overpressure in the main roadway and the distance from the outburst port showed a decreasing trend. The highest value of temperature in the roadway increased by 0.25 • C and the highest value of gas concentration reached 38.12% during the experiment. With the action of shock air flow, the pulverized coal transportation in the roadway could be roughly divided into three stages, which are the accelerated movement stage, decelerated movement stage and the particle settling stage respectively. Total of 180.7 kg pulverized coal of outburst in this experiment were erupted, and most of them were accumulated in the main roadway. Through the analysis of the law of outburst shock wave propagation, a shock wave propagation model considering gas desorption efficiency was established. The relationships of shock wave overpressure and outburst intensity, gas desorption rate, initial gas pressure, cross section and distance of the roadway were obtained, which can provide a reference for the protection of coal and gas outburst and control of catastrophic ventilation.Keywords: coal and gas outburst; laboratory simulation experiment; two-phase flow of a mixture of pulverized coal and gas; shock wave; propagation model

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Role of the rapid gas desorption of coal powders in the development stage of outbursts

Abstract: Based on the desorption experiments of coal particles with different sizes, the possibility of the existence of coal powders in the outburst development stage was studied from the perspective of

Cited by 160 publications

References 33 publications

Experimental investigation on dynamic strength and energy dissipation characteristics of gas outburst‐prone coal

Experimental investigation on dynamic strength and energy dissipation characteristics of gas outburst‐prone coal

Correlation between coal and gas outburst risk and adsorption properties of coal seams

Experimental Research on the Impactive Dynamic Effect of Gas-Pulverized Coal of Coal and Gas Outburst

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