Fractal fracture characteristics and acoustic emission analysis of soft rock-coal combinations under low-frequency disturbance

To explore the fracture mode and failure characteristics of soft rock-coal combinations under different disturbance amplitudes, this paper conducted dynamic uniaxial compression tests under different disturbance amplitudes. The results indicate that low-frequency disturbances can weaken the load-bearing capacity of the specimen. The failure modes of specimens vary under different disturbance amplitudes, and low amplitude disturbances are not sufficient to cause overall cracking and failure of the specimens. In addition, as the disturbance amplitude increases, the fractal dimension of the composite after fracture shows a fluctuating trend, reaching its maximum value at 3 MPa and its minimum value at 4 MPa, with an overall range of 1–3. Finally, the absolute energy and waveform characteristics of acoustic emission can display the fracture damage of the specimen during the disturbance process. This study provides a theoretical basis for understanding and preventing coal rock dynamic disasters.