Reaction Degree and Selecting Sensitive Geological Factors for Coal and Gas Outburst Forecast

2014 ◽  
Vol 13 (3) ◽  
pp. 597-600
Author(s):  
Caifang Wu ◽  
Teng Li
Keyword(s):  
Coal And Gas Outburst ◽  
Gas Outburst ◽  
Geological Factors ◽  
Reaction Degree

Application of Radar Velocity Tomography for Detecting Coal and Gas Outburst in Deep Coal Mining

2014 ◽  
Vol 513-517 ◽  
pp. 3659-3662
Author(s):  
Cui Du ◽  
Xin Jun Xu ◽  
Xing Yu Li
Keyword(s):  
Geophysical Methods ◽  
Coal And Gas Outburst ◽  
Mine Safety ◽  
Gas Outburst ◽  
Safety Production ◽  
Geological Factors ◽  
Radar Velocity ◽  
Mining Coal ◽  
Ground Penetrating ◽  
Velocity Tomography

Among the main geological factors to cause the disasters of mine safety production in deep mining, coal and gas outburst is the first major calamity that restricts colliery exploiting. Aiming at this problem, current geophysical methods were reviewed and compared, and the velocity tomography technology using ground penetrating radar was studied. Two models with ground stress anomaly and collapse columns were built and inverted using LSQR algorithm, respectively. The results show that the proposed method gives very consistent results with respect to the models information, and uncertain features of inverted models were identified accurately. This verified radar velocity tomography is effective and practical.

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

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Qingyi Tu ◽  
Yuanping Cheng ◽  
Sheng Xue ◽  
Ting Ren ◽  
Xiang Cheng
Keyword(s):  
Tectonic Stress ◽  
Coal And Gas Outburst ◽  
Future Research ◽  
Tectonic Movement ◽  
Gas Outburst ◽  
Research Areas ◽  
Dynamic Factors ◽  
Restructuring Process ◽  
Geological Factors ◽  
Inducing Factors

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.

Deformation Analysis for Coal and Gas Outburst Cavity

2011 ◽  
Vol 121-126 ◽  
pp. 2607-2613
Author(s):  
Qian Ting Hu ◽  
Wen Bin Wu ◽  
Guo Qiang Cheng
Keyword(s):  
Damage Zone ◽  
Coal And Gas Outburst ◽  
Gas Content ◽  
Combination Method ◽  
Deformation Analysis ◽  
Failure Zone ◽  
Finite Element Code ◽  
Cavity Volume ◽  
Gas Emission ◽  
Gas Outburst

Outburst cavity formed during coal and gas outburst can be pear shaped, elliptical, or just like an irregularly elongated ellipsoid, its capacity is always smaller than the volume of ejected coal. And the gas emission quantity is almost 4 to 10 times as gas content in ejected coal. These are two different expressions of the same problem. To find the reasons for the decrease of outburst cavity volume and the increase of gas emission quantity per ton, by using the finite element code ANSYS, the damage zone and the failure zone of the outburst cavity were determined based on the static and dynamic combination method. In this paper, the reason for the decrease of the outburst volume was explained.

scholarly journals Mechanical criterion for coal and gas outburst: a perspective from multiphysics coupling

2021 ◽  
Author(s):  
Ting Liu ◽  
Baiquan Lin ◽  
Xuehai Fu ◽  
Ang Liu
Keyword(s):  
Control Method ◽  
Risk Identification ◽  
Controlling Factors ◽  
Gas Pressure ◽  
Critical Values ◽  
Coal And Gas Outburst ◽  
Strong Interactions ◽  
Gas Outburst ◽  
Multiphysics Coupling ◽  
Coal Strength

AbstractAlthough a series of hypotheses have been proposed, the mechanism underlying coal and gas outburst remains unclear. Given the low-index outbursts encountered in mining practice, we attempt to explore this mechanism using a multiphysics coupling model considering the effects of coal strength and gas mass transfer on failure. Based on force analysis of coal ahead of the heading face, a risk identification index Cm and a critical criterion (Cm ≥ 1) of coal instability are proposed. According to this criterion, the driving force of an outburst consists of stress and gas pressure gradients along the heading direction of the roadway, whereas resistance depends on the shear and tensile strengths of the coal. The results show that outburst risk decreases slightly, followed by a rapid increase, with increasing vertical stress, whereas it decreases with increasing coal strength and increases with gas pressure monotonically. Using the response surface method, a coupled multi-factor model for the risk identification index is developed. The results indicate strong interactions among the controlling factors. Moreover, the critical values of the factors corresponding to outburst change depending on the environment of the coal seams, rather than being constants. As the buried depth of a coal seam increases, the critical values of gas pressure and coal strength decrease slightly, followed by a rapid increase. According to its controlling factors, outburst can be divided into stress-dominated, coal-strength-dominated, gas-pressure-dominated, and multi-factor compound types. Based on this classification, a classified control method is proposed to enable more targeted outburst prevention.

The Impact Analysis of Coal’s Elastic Energy on the Coal and Gas Outburst Shock Wave

2012 ◽  
Vol 616-618 ◽  
pp. 390-395
Author(s):  
Cheng Wu Li ◽  
Tian Bao Gao ◽  
Shan Yang Wei ◽  
Teng Li
Keyword(s):  
Shock Wave ◽  
Elastic Energy ◽  
Impact Analysis ◽  
Dynamic Theory ◽  
Coal And Gas Outburst ◽  
Calculation Formula ◽  
Theory Analysis ◽  
Gas Outburst ◽  
Quantitative Calculation ◽  
The Impact

According to the gas dynamic theory, this paper deduces the approximate calculation formula on elastic energy of a tons of coal through theory analysis, and then gets the quantitative calculation method between incident overpressure and reflected overpressure of the coal and gas outburst shock wave. The calculation formula in this paper is in line with the measured values, and so its validity has been verified. The analysis result shows that the effect of the elastic energy during the process of coal and gas outburst should be considered when the depth of the coal seam is great and the coal’s modulus of elasticity is small.

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