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Mechanical behavior and damage mechanism of loaded coal and rock

Feng Luo (School of Mining and Geomatics Engineering, College of Mining and Geomatics Engineering, Hebei University of Engineering, Handan, China)
Guodong Li (School of Mining and Geomatics Engineering, College of Mining and Geomatics Engineering, Hebei University of Engineering, Handan, China)
Hao Zhang (School of Mining and Geomatics Engineering, College of Mining and Geomatics Engineering, Hebei University of Engineering, Handan, China)

World Journal of Engineering

ISSN: 1708-5284

Publication date: 12 June 2017

Abstract

Purpose

The purpose of this paper is to obtain the mechanical behavior and damage mechanism of the coal and rock near the stope under the stress state and stress paths of the surrounding rock with the dynamic mining.

Design/methodology/approach

Through the three-axial compression test and the uniaxial compression test by meso experiment device, the mechanical behavior and fracture evolution process of coal and rock were studied, and the acoustic emission (AE) characteristics under uniaxial compression of the coal and rock were contrasted.

Findings

Under the three-axial compression, the strength of coal and rock enhance significantly by confining pressure. The volume of outburst coal shows obvious stages: compression is followed by expansion. The coal first appear to undergo compaction under vertical stress due to volume decrease, but with the development of micro- and macro-cracks, the specimens appeared to expand; under the uniaxial compression, through the comparison of stress–strain relationship and the crack propagation process, stress drop and fracture of coal have obvious correlation. The destruction of coal was gradual due to the slow and steady accumulation of internal damage. Due to the influence of the end effect, the specimens show the “conjugate double shear failure”. The failure process of the coal and rock and the characteristics of the AEs have a corresponding relationship: the failure causes a large number of AE events. Before the events peak, there was an initial stage, calm growth stage and explosive growth stage. There were some differences between the rock and coal in the characteristics of the AE.

Originality/value

These research studies are conducted to provide guidance on the basis of mine disaster prevention and control.

Keywords

Acknowledgements

This research is financially supported by the National Natural Science Foundation of China (51474039, 51404046), Science and Technology Research Program for Colleges and Universities supported by Education Department of Hebei (QN2015069, BJ2016010).

Citation

Luo, F., Li, G. and Zhang, H. (2017), "Mechanical behavior and damage mechanism of loaded coal and rock", World Journal of Engineering, Vol. 14 No. 3, pp. 200-207. https://doi.org/10.1108/WJE-03-2017-0059

Publisher

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Emerald Publishing Limited

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