Mesoscopic Crack Initiation, Propagation, and Coalescence Mechanisms of Coal Under Shear Loading
The process of coal and rock shear failure is accompanied by crack formation and coalescence. A better understanding of the crack initiation, propagation, and coalescence processes is conducive to the study of failure processes of coal and rock in underground mines.
Since Sprunt and Brace (1974) introduced scanning electron microscopy (SEM) into rock micro-fracture research, many related studies have followed: Wu and Thomsen (1975) investigated the cumulative number of micro-ruptured Westerly granite samples based on uniaxial compression creep experiments. Tapponnier and Brace (1976) studied the stress-induced crack propagation in Westerly granites. Kranz (1979a, b, 1980) revealed crack growth and development during Barre granite creep. Ingraffea and Heuze (1980) demonstrated crack propagation in limestone and granodiorite under uniaxial compression. Petit and Barquins (1988) analysed crack propagation in sandstone under uniaxial compression. Scholars then began to focus...
KeywordsRock mechanics Shear failure Surface cracks Crack growth
List of symbols
Number of cracks
- ai1, ai2,…, ain
The actual lengths of each of n cracks appearing on an observation surface at a given time ti (mm)
- li1, li2,…, lin
The effective length of each of n cracks appearing on an observation surface at a given time ti (mm)
The effective length of crack j appearing on an observation surface at a given time ti (mm)
The total effective length of surface cracks appearing on an observation surface at a given time ti (mm)
The average rate of propagation of cracks at a given time ti (mm/s)
This research was supported by the National Natural Science Foundation of China (Grant no. 51474040), the Science and Technology Research Project of Hebei Province (Grant no. QN2017031), the Basic and Frontier Research Projects of Chongqing (cstc2016jcyjA0117), the Key Research Development Project of Hebei Province (Grant no. 18273815D), and the Fundamental Research Funds for the Central Universities (Grant no. 106112017CDJQJ248825). In addition, the authors would like to express their sincere gratitude to the editor and the anonymous reviewers for their valuable comments, which have greatly improved this paper.
- Mayo S, Josh M, Nesterets Y, Esteban L, Pervukhina M, Clennel MB, Anton M, Hall C.(2015) Quantitative micro-porosity characterization using synchrotron micro-CT and xenon K-edge subtraction in sandstones, carbonates, shales and coal. Fuel 154:167–173. https://doi.org/10.1016/j.fuel.2015.03.046 CrossRefGoogle Scholar