To investigate the influence of mining rate on the development of fracture structures in water-bearing coal after implementing water injection for rockburst prevention in the working face

uniaxial compression tests at various loading rates were conducted on coal samples with different moisture contents (Dr

Se

Sa). The mechanical properties and acoustic emission characteristics of these water-bearing coal samples were analyzed under different loading rates. Using fractal dimension and scanning electron microscope (SEM)

the fracture mechanism of the microstructure of these coal samples was revealed. The results show that an increase in water content weakens the peak strength of coal samples

induces a delay in acoustic emission ringing count and energy signals

and the lubrication effect of water reduces the proportion of tensile cracks in coal samples. Particle hydration is the primary reason for the reduction in brittleness and the alteration of fracture characteristics

with fractures transitioning from brittle to plastic and from transgranular to intergranular. An increase in loading rate inhibits the full propagation of internal cracks in coal samples

enhances their peak strength and elastic modulus

and reduces cumulative damage during the initial loading stage

resulting in acoustic emission ringing counts and energy signals gradually approaching their peak values. The cumulative energy of acoustic emissions shifts from a pattern of long-term slow increase followed by short-term sudden increase to a pattern of short-term slow increase followed by short-term sudden increase. The faster the loading rate

the smaller the slope of the k-value on the curve (where is the total mass of the fragments

is the mass of fragments smaller than the equivalent side length )

the larger the fractal dimension

the less fragmented the coal sample

and the brittleness of the coal sample is enhanced

altering its fracture morphology. The research results can provide a solid experimental basis for rapid

safe

and efficient production in working faces.