Experimental determination of the outburst threshold value of energy strength in coal mines for mining safety

Xue, Sheng; Zheng, Chen; Zheng, Xiaoliang; Jiang, Bingyou; Li, Yaobin; Wang, Zhigen

doi:10.1016/j.psep.2020.03.034

Cited by 31 publications

(13 citation statements)

References 24 publications

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“…As can be seen from Figure 4, the fracture gas pressure at 5 m in front of the working face changed greatly, and the outburst duration was generally less than 60 s. Therefore, the gas expansion at 5 m in front of the work-ing face at the moment of 60 s was selected for analysis. According to formula (18), the gas expansion energy of outburst coal seam under different conditions can be calculated.…”

Section: Influencing Factors Of Gas Expansion Energymentioning

confidence: 99%

“…Through experimental research, Liang et al [17] obtained that the influence of gas pressure, coal particle size, and water content on initial gas release expansion energy decreases in turn, and the gas expansion energy increases significantly with the increase of gas pressure. Xue et al [18] obtained that the minimum energy required for outburst is about 1.1 MJ/m 3 ; compared with the free gas energy, the desorption gas energy of coal plays a decisive role in the initiation and spread of outburst. Lu et al [19] analyzed the outburst energy under three different conditions (normal coal, deformed coal, and coal combination) by constructing a numerical analysis model.…”

Section: Introductionmentioning

confidence: 99%

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Gas Expansion Energy Model and Numerical Simulation of Outburst Coal Seam under Multifield Coupling

Cao¹,

Hu²,

Yong-liang³

et al. 2021

Geofluids

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Due to the insufficient understanding of the outburst mechanism, the coal and gas outburst disasters in China are more serious. Gas expansion energy is the main source of energy that causes outburst. In order to explore the distribution law of gas expansion energy in outburst coal seams, a gas-solid coupling equation of outburst coal seams was established. The distribution law of coal stress field, deformation field, gas flow field, and gas expansion energy were simulated and analyzed by using COMSOL Multiphysics. The results showed that from the excavation face to the deep part of coal seam, the stress presented unloading zone, stress concentration zone, and original stress zone. The volumetric strain and permeability reached the minimum, while the gas pressure reached the maximum at the peak value of vertical stress. As time goes on, the gas pressure in the fracture near the working face gradually decreased and was less than the pressure in coal matrix. The total gas expansion energy consists of free gas and desorption gas expansion energy. Affected by the excavation, free gas expansion energy maintained a constant value in the original coal seam and gradually decreased in the area close to the working face. The expansion energy provided by desorption gas was zero in the original coal seam. And it first increased and then decreased rapidly near the working face. Compared with stress and coal seam thickness, gas pressure and initial diffusion coefficient had significant influence on gas expansion energy of coal seam. When the diffusion coefficient was greater than 1e-9 m2/s, the gas expansion energy of the coal seam near the working face was significantly higher than that of the original coal seam, which had the risk of inducing outburst.

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Section: Influencing Factors Of Gas Expansion Energymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Gas Expansion Energy Model and Numerical Simulation of Outburst Coal Seam under Multifield Coupling

Cao¹,

Hu²,

Yong-liang³

et al. 2021

Geofluids

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“…Coal and gas outbursts (hereinafter referred to as outbursts) are a kind of sudden dynamic disaster in underground coal mines which have complicated processes [1,2]. Since the catastrophe process is accompanied by considerable failure effect, outbursts are a great threat to safety exploitation of coal resources, thus becoming a wide concern around the world [3]. In particular, outbursts during coal mining in China are more serious, which is determined by the extremely complicated occurrence environment of coal resources in China [4].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Coal and Gas Outburst Mechanism from the Perspective of Tectonic Movement

Cheng

Xue

et al. 2021

Geofluids

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Coal and gas outburst is the extreme instability caused by stress, gas, and coal. In this review article, dominant factors and inducing factors of outburst were summarized; geologic features of typical outburst cases and the effects of tectonic movement on outbursts were analyzed; the outburst stages with considerations to geologic factors were divided. It was found that inducing factors, including buried depth, tectonic movement, gas composition, coal seam conditions, overlying/underlying rock conditions, and mining mode, control the outburst by influencing the dominant factors (stress, gas, and coal). Among them, tectonic movement is the key of outburst. Influenced by tectonic movement, the primary structure of coals is damaged/pulverized due to the tectonic stress and unique tectonic mode, resulting in the formation of tectonic coals. When external dynamic factors are changed, tectonic coals are crucial to outburst control for its evolution of porous structure as well as the unique mechanical behaviors and gas flowing responses. Besides, the preparation stage of outburst includes the tectonic process and mining process. The former one refers to the restructuring process of the original coal-bearing strata by tectonic movement, while the mining process is the prerequisite of outburst and it refers to the disturbance of human mining activities to the initial coal seams. It is suggested that more work is required on geological factors of outburst, and a few research areas are proposed for future research.

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“…Among them, coal and gas outburst (hereinafter referred to as outburst) attracts worldwide attention toward mine safety (Wang et al, 2020). Outburst is the rapid release of a large quantity of gas in conjunction with ejection of coal into the mine working areas (Yang et al, 2021), which is usually accompanied by enormous destruction effect (Xue et al, 2020). Due to the complexity and non-repeatability of outburst, it is difficult to explain the outburst mechanism under different geological conditions with unified theories (Liu et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Guiding Effect of Soft Tectonic Coal on Coal and Gas Outburst and its Experimental Study

Tu¹,

Xue²,

Cheng³

et al. 2021

Preprint

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Soft tectonic coal commonly exists in coal and gas outburst zones. The physical simulation experiment was carried out to reproduce the influences of soft coal area on the outburst, and the guiding action mechanism of soft tectonic coal on the outburst was investigated. This study concludes that the amount of outburst coal in the experiments of group with local existence of soft coal area are relatively lower. The outburst coal amount (3.8035 kg) and relative outburst intensity (21.02%) in the GR5# experiment were both lower than that in the GN6# experiment of control group. However, the outburst coal in the experiments of group with local existence of soft coal area could be commonly migrated to a long distance, the maximum throwing distances in the three experiments were all over 16.73 m, reaching as high as 20.10 m. Under the gas pressure of 0.30 MPa in the group with local existence of soft coal area, the outburst coal amount (2.7355 kg) was smaller than the amount (2.803 kg) of pulverized coal filled, and the 2.0 cm coal pillar experiences failure only nearby the outburst mouth. As the gas pressure increases, the failure degree of the coal pillar becomes higher and higher until complete failure. The outburst development sequence is changed due to the existence of the soft tectonic soft area. Once the sealing conditions are destructed, the outburst firstly develops in the soft tectonic coal area. Nevertheless, sufficient energy is supplied to transport the coal mass in the soft tectonic coal area to a farther distance, while the residual outburst energy can just result in the outburst of a small quantity of coal masses in the normal area. This research will be of great scientific significance for explaining the soft tectonic coal-induced change of outburst starting and development sequence.

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Experimental determination of the outburst threshold value of energy strength in coal mines for mining safety

Cited by 31 publications

References 24 publications

Gas Expansion Energy Model and Numerical Simulation of Outburst Coal Seam under Multifield Coupling

Gas Expansion Energy Model and Numerical Simulation of Outburst Coal Seam under Multifield Coupling

Analysis of the Coal and Gas Outburst Mechanism from the Perspective of Tectonic Movement

Guiding Effect of Soft Tectonic Coal on Coal and Gas Outburst and its Experimental Study

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