TY - JOUR
T1 - Numerical investigation on crack development and energy evolution of stressed coal-rock combination
AU - Zhang, Heng
AU - Lu, Cai Ping
AU - Liu, Bin
AU - Liu, Yang
AU - Zhang, Nong
AU - Wang, Hong Yu
PY - 2020/9
Y1 - 2020/9
N2 - To uncover the failure and instability mechanism of coal-rock combination under loading, it is very crucial to investigate crack development and energy evolution. In this work, the uniaxial compressive and Brazilian split tests of coal-rock combinations were first performed. Secondly, the corresponding numerical models were built using the UDEC-Trigon method. Based on numerical results, the number, length and macroscopic area of cracks during failure and instability were determined, and the crack development and energy evolution rules were analysed. The main conclusions were obtained as follows: 1) the stress thresholds of crack initiation and damage of coal-rock combination rose with the increasing height ratio of coal to rock. The maximum event count of acoustic emission (AE) appeared earlier than the peak strength; 2) the failure and instability of coal-rock combination occurred when crack propagation and connection in central coal exceeded the damage limit. The shear failure was dominant mechanical behaviour of coal with the ratio 9:1 of shear to tensile fractures. The cracks connection was presented as a shear failure surface with an inclination angle of 15°–30° in coal and a vertical tensile failure plane in rock; and 3) the energy evolution in coal-rock combination was described as follows: the larger the height ratio of coal to rock is, the higher the cumulative energy is, and the faster the speed of energy dissipation is, indicating the higher risk of rockburst triggered by failure and instability of coal-rock combination.
AB - To uncover the failure and instability mechanism of coal-rock combination under loading, it is very crucial to investigate crack development and energy evolution. In this work, the uniaxial compressive and Brazilian split tests of coal-rock combinations were first performed. Secondly, the corresponding numerical models were built using the UDEC-Trigon method. Based on numerical results, the number, length and macroscopic area of cracks during failure and instability were determined, and the crack development and energy evolution rules were analysed. The main conclusions were obtained as follows: 1) the stress thresholds of crack initiation and damage of coal-rock combination rose with the increasing height ratio of coal to rock. The maximum event count of acoustic emission (AE) appeared earlier than the peak strength; 2) the failure and instability of coal-rock combination occurred when crack propagation and connection in central coal exceeded the damage limit. The shear failure was dominant mechanical behaviour of coal with the ratio 9:1 of shear to tensile fractures. The cracks connection was presented as a shear failure surface with an inclination angle of 15°–30° in coal and a vertical tensile failure plane in rock; and 3) the energy evolution in coal-rock combination was described as follows: the larger the height ratio of coal to rock is, the higher the cumulative energy is, and the faster the speed of energy dissipation is, indicating the higher risk of rockburst triggered by failure and instability of coal-rock combination.
KW - Acoustic emission
KW - Coal-rock combination
KW - Crack development
KW - Energy evolution
KW - Rockburst
UR - http://www.scopus.com/inward/record.url?scp=85088922860&partnerID=8YFLogxK
U2 - 10.1016/j.ijrmms.2020.104417
DO - 10.1016/j.ijrmms.2020.104417
M3 - Article
AN - SCOPUS:85088922860
SN - 1365-1609
VL - 133
JO - International Journal of Rock Mechanics and Mining Sciences
JF - International Journal of Rock Mechanics and Mining Sciences
M1 - 104417
ER -