Comparison of Energy Evolution Characteristics of Intact and Fractured Coal under True Triaxial Progressive Stress Loading

Abstract

The underground coal mining process is closely associated with frequent energy storage and consumption of coal mass with natural and induced fractures. Exploring the energy evolution characteristics of intact and fractured coal samples could be helpful for dynamic disaster control. In this study, laboratory true triaxial tests on the energy evolution characteristics of intact and fractured coal samples have been carried out and systematically discussed. The results show that the brittleness and peak strength are weakened due to the presence of macro-fractures in coal. The mean peak strength and brittleness for fractured coal are 29.00% and 74.59% lower than the intact coal samples. For both intact and fractured coal, the energy evolution curves are closely related to the deformation stages under true triaxial stresses. When subjected to the same intermediate stress, intact coal stores more elastic strain energy compared to fractured coal. Additionally, the rate of dissipative energy variation is two–three times lower in fractured coal samples compared to intact coal samples.

Study on the Energy Evolution Law and Bursting Liability of Coal Failure with Different Joint Inclination Angles

“…Sci. 2024, 14, 1120 2 of 16 combinations, and original cracks on the energy evolution of coal rock failure [19][20][21]. However, previous studies on energy evolution laws have mostly focused on intact coal rocks or rocks with joints.…”