Citation

Xiao P, Gao Z, Shuang H, Wu M, Cheng Y, Guo C. China Saf. Sci. J. 2022; 32(11): 65-73.

Copyright

(Copyright © 2022, China Occupational Safety and Health Association, Publisher Gai Xue bao)

DOI

10.16265/j.cnki.issn1003-3033.2022.11.2690

PMID

unavailable

Abstract

In order to study the influence of loading rate on the evolution of coal fracture, uniaxial compression tests of coal under different loading rates were carried out. Taking raw coal samples as the research object, the relationship between coal mechanical parameters, deformation field evolution cloud map and acoustic emission signal parameters was analyzed by combining digital speckle technology and acoustic emission technology. The research shows that the compressive strength and elastic modulus of coal increase gradually with the increase of loading rate. The compressive strength increases by 25. 49%, and the elastic modulus increases by 51. 55%. The evolution nephogram of the coal deformation field and the spatial distribution of acoustic emission events can indicate the whole process of fracture development, expansion and fracture. With the increase of loading rate, the failure type of coal body changes from tensile failure to tensile shear composite failure. The relative displacement rate of the localization zone of the coal surface deformation field decreases gradually, and the peak count, peak energy and the number of acoustic emission events increase, while the cumulative count and cumulative energy decrease. The evolution nephogram of the deformation field and the spatial distribution of acoustic emission events can better reflect the evolution characteristics of fracture development, expansion and fracture during coal loading. © 2022 China Safety Science Journal. All rights reserved.

Language: zh