Influence of Confining Pressure on Nonlinear Failure Characteristics of Coal Subjected to Triaxial Compression

Qiuping Li, Jie Liu (), Shouqing Lu, Zaiquan Wang, Hao Wang, Yimeng Wu, Yupu Wang, Di Ying and Mingjie Li
Additional contact information
Qiuping Li: Department of Safety Engineering, Qingdao University of Technology, Qingdao 266520, China
Jie Liu: Department of Safety Engineering, Qingdao University of Technology, Qingdao 266520, China
Shouqing Lu: Department of Safety Engineering, Qingdao University of Technology, Qingdao 266520, China
Zaiquan Wang: School of Civil Engineering, Qingdao University of Technology, Qingdao 266520, China
Hao Wang: Department of Safety Engineering, Qingdao University of Technology, Qingdao 266520, China
Yimeng Wu: Department of Safety Engineering, Qingdao University of Technology, Qingdao 266520, China
Yupu Wang: Department of Safety Engineering, Qingdao University of Technology, Qingdao 266520, China
Di Ying: Department of Safety Engineering, Qingdao University of Technology, Qingdao 266520, China
Mingjie Li: Department of Safety Engineering, Qingdao University of Technology, Qingdao 266520, China

IJERPH, 2022, vol. 20, issue 1, 1-17

Abstract: The stress of a coal seam increases with an increase in the mining depth, which makes the failure mechanism of a coal mass more complex. To reveal the deformation and failure law of deep coal, a series of triaxial experiments was carried out via laboratory experiments and numerical simulation experiments to analyze the influence of the confining stress on the nonlinear failure characteristics of coal. Based on the crack-propagation model, the values for the inelastic flexibility S 1 and the damage variable D were calculated. The results showed that the value of S 1 decreased with an increase in the confining stress, which indicated that the increase in the confining pressure could inhibit the crack propagation and that the inhibitory effect was more obvious when the confining pressure increased in a small range of 4 to 12 MPa. The damage variable decreased with an increase in the confining pressure at the yield point; moreover, with an increase in the initial confining pressure, the damage rate gradually decreased. The coal body changed from the compression state to the expansion state when moving from the yield point to the peak point, and the compression value of the yield point and the dilation value of the peak point increased with the increase in the confining pressure. After the coal body entered the yield stage, the change in the confining pressure had a more significant effect on the damage to the coal body.

Keywords: triaxial compression; crack propagation; damage variable; coal-body destruction (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2022
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