The Energy Principle of Coal and Gas Outbursts: Experimentally Evaluating the Role of Gas Desorption
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ORIGINAL PAPER
The Energy Principle of Coal and Gas Outbursts: Experimentally Evaluating the Role of Gas Desorption Yang Lei1,2,3 · Yuanping Cheng1,2,3 · Ting Ren4 · Qingyi Tu1,2,3 · Longyong Shu5 · Yixuan Li1,2,3 Received: 12 February 2020 / Accepted: 8 September 2020 © Springer-Verlag GmbH Austria, part of Springer Nature 2020
Abstract Outburst energy is a major factor influencing coal and gas outbursts, albeit its estimation is difficult owing to the lack of amenable means for quantification of gas desorption. In the past decades, determining the mechanism of outbursts is one of the most challenging issues in rock mechanics. In this study, a triaxial coal and gas outburst simulation system was employed to perform simulated experiments using He (to rule out the influence from gas ad-desorption), N 2, and C O2. This facilitated understanding of the energy principle underlying the said outbursts and evaluation of the effects of gas desorption on outburst development. Results of this study indicate that outburst energy and energy consumption are influenced by several factors, including outburst pressure, outburst intensity, ejection distance, and particle size of ejected coal. Among these, gas desorption demonstrates the greatest influence when performing controlled tests (using He). Considering the effects of gas desorption, the total outburst energy can be increased by 1.35–2.95 times, thereby causing an enormous increase in the destructive potential of outbursts. Additionally, values of the coal crushing and transport energies can be enhanced by the order of 118.9–206.6% and 157.8–406.6%, respectively, thereby resulting in a stronger conveying capacity of outburst coal– gas flow along with severe coal fragmentation. A further analysis of the energy distribution indicated that in the development stage, gas desorbed from coal acts as the force driving coal transport, whereas free gas energy is mainly consumed during coal crushing. Findings of this study highlight the importance of quantifying contributions of coal gas towards effective interpretation of outburst-causing mechanisms. Keywords Outburst mechanism · Gas desorption · Experimental simulation · Energy analysis List of symbols A1 Elastic energy of coal (J) E1 Elastic energy of unit coal mass (J/m3) ML Mass of coal loaded in chamber (kg) * Yuanping Cheng [email protected] 1
Key Laboratory of Coal Methane and Fire Control, Ministry of Education, China University of Mining and Technology, Xuzhou 221116, China
2
School of Safety Engineering, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China
3
National Engineering Research Center for Coal and Gas Control, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China
4
School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW 2522, Australia
5
Mine Safety Technology Branch, China Coal Research Institute, Beijing 100013, China
W2 Energy consumption of crushed coal (J) E Elastic modulus (MPa) P1 Gas pr
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