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TIME-VARYING MULTIFRACTAL ANALYSIS OF CRACK PROPAGATION AND INTERNAL FRACTURE PROCESS OF COAL UNDER DYNAMIC LOADING

Civil Engineering and Architecture, Anhui University of Technology, Maanshan, Anhui 243002, P. R. China

State Key Laboratory Cultivation Base for Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo Henan 454003, P. R. China

E-mail Address: junjuncumt@126.com

Corresponding author.

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ENYUAN WANG

Key Laboratory of Gas and Fire Control for Coal Mines, China University of Mining and Technology, Xuzhou Jiangsu 221116, P. R. China

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QISONG HUANG

Civil Engineering and Architecture, Anhui University of Technology, Maanshan, Anhui 243002, P. R. China

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HOUCHENG DING

Civil Engineering and Architecture, Anhui University of Technology, Maanshan, Anhui 243002, P. R. China

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, and

LONG DANG

China Coal Technology and Engineering Group, Shenyang Research Institute, Shenyang, Liaoning 110016, P. R. China

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https://doi.org/10.1142/S0218348X21500894Cited by:6 (Source: Crossref)

Abstract

Coal failure behavior under dynamic loading is significant for dealing with the failure issues encountered in underground coal mines. In this study, the crack propagation and internal fracture process of coal under dynamic loading were investigated by a split Hopkinson pressure bar (SHPB) experimental system and numerical approach, respectively. The experimental and numerical results show that the coal crack propagation and internal fracture surface manifest significant multifractal features. Further, multifractal analysis suggests that the multifractal feature becomes more and more significant during the dynamic loading. The formation mechanism of the multifractal features was further discussed, and the result demonstrates that the crack propagation path within coal is essentially a multifractal structure, thus causing the total fracture behavior of coal to show multifractal features under dynamic loading. Moreover, the multifractal spectrum parameter $Δ α_{L}$ was proved to be closely related to the brittle fracture property of coal, which transpires that the multifractal feature is feasible to evaluate the coal brittleness under dynamic loading and also applicable to predict the coal failure risk in underground coal mines.

Keywords:

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