Measurement of uniaxial compression mechanical properties of thermally dried coal samples by energy and fragmentation characteristic analyses

This study aimed to determine the effects of different drying temperatures on the mechanical properties of coal samples under axial compression. Processed, screened, and water-saturated coal samples were subjected to a blast drying treatment at 25, 50, 75, 100, and 125 degrees C for 4 h. Uniaxial compression mechanical experiments were then performed and the fragments were collected and counted after destruction of the coal samples. Based on the above experimental results, the intrinsic nature of the changes in the mechanical properties of uniaxial compression of coal samples after thermal drying is revealed by the energy evolution and the characteristics of fragment distribution. The results show that with an increase in drying temperature, the energy storage capacity of the coal sample tended to first decrease and then increase, and the energy release capacity gradually increased after the peak. The EESERR index increased exponentially with increasing drying temperature after the uniaxial compression of the coal sample reached the damaged state. In addition, as the drying temperature increased, the brittleness of the coal sample was enhanced, the intensity of uniaxial compression damage increased signifi-cantly, the fragments tended to be distributed in smaller sizes, and the degree of fragment chaos increased.

Automated summary

This study investigated the effects of different drying temperatures on the mechanical properties of coal samples under axial compression. The results revealed that the energy storage capacity of the coal sample decreased and then increased with increasing drying temperature, and the energy release capacity increased gradually after reaching the peak. The EESERR index exponentially increased with drying temperature after the coal sample reached the damaged state. Additionally, as the drying temperature increased, the brittleness of the coal sample increased, the intensity of compression damage increased significantly, and the fragments tended to be distributed in smaller sizes with increased chaos.