A recent study by researchers led by Pengxiang Zhao investigates how varying interface angles affect the mechanical properties and energy dissipation characteristics of coal-rock composites during uniaxial compression. This research sheds light on the diminishing compressive strength and elastic modulus associated with steeper interface angles, thereby enhancing our comprehension of the factors contributing to mine safety and stability.
Mining operations increasingly deal with the complex nature of coal and rock interactions as operations progress to greater depths. Rising instances of coal and gas outbursts pose significant risks. A key focus of this study was the mechanical properties and energy characteristics of coal-rock combinations, particularly under conditions similar to those found during standard mining operations. This includes destructive phenomena such as the accumulation of energy at interface angles formed between these layers.
The study employed rigorous experimental methods, utilizing the DYD-10 universal testing machine to test multiple specimens of coal-rock combinations with interface angles set at 25°, 30°, 35°, 40°, and 45°. Each specimen underwent uniaxial compression until failure, allowing researchers to capture stress-strain curves and energy dissipation patterns effectively.
Data analysis indicated significant findings: the compressive strength values upon reaching interface angles of 25° and 30° measured 1.71 and 1.61 MPa respectively. The measured value at 35° was 1.43 MPa, and as interface angles approached 40° and 45°, compressive strength showed notable declines of 1.29 and 1.19 MPa respectively. This steady decrease indicates how interface angles critically impact specimen performance and structural integrity during loading.
A notable observation relates to energy dynamics during failure. Researchers categorized energy evolution characteristics over distinct stages, encompassing compaction, elastic response, plastic fracture, and post-peak failure. The most significant energy storage occurred during the initial elastic and fracture stages, contributing to over 90% of total energy presence during these phases of loading. The energy dissipation coefficient, which quantifies the ratio of elastic energy to dissipated energy, displayed notable increases—suggesting variations directly correlated with the interface angles involved.
By establishing the relationship between interface angles, mechanical strength, and energy dissipation characteristics, the study elucidates broader implications on how coal-rock combinations behave under stress. This insight can significantly inform mining strategies, particularly concerning minimizing risks associated with rock burst disasters.
While the initial findings contribute valuable perspectives on the subject, future investigations can continue to explore the underlying mechanisms behind energy transformation during coal-rock interaction.