ABSTRACT In response to the issue that existing deep soft high‐gas coal seam floor blasting permeability enhancement techniques neglect the influence of in situ stress, a bidirectional loading gas‐solid coupling blasting simulation system was established in the laboratory to achieve multidimensional damage characterization. Comparative simulation experiments were conducted under different burial depths. The results indicate that in situ stress significantly inhibits the propagation of blasting‐induced cracks, with the inhibitory effect intensifying with increasing in situ stress levels. As the burial depth H increases from 0 to 1000 m, the damage reduction in the S3 profile of the coal mass at the distal end of the test block becomes more pronounced, demonstrating that in situ stress exerts a stronger inhibitory effect on crack propagation in low‐strength media at greater distances. In situ stress attenuates the propagation intensity of blasting stress waves, with low‐strength media showing greater sensitivity to the attenuation effect of blasting waves under in situ stress. Numerical simulations using ANSYS/LS‐DYNA software revealed that the damage induced by floor blasting is primarily concentrated at the interface between the floor and coal‐rock, with in situ stress limiting the extent of the crack zone while having minimal impact on the crushed zone. A predictive model based on fractal dimension D and damage quantity w was developed, effectively assessing the degree of blasting damage in coal and rock under different in situ stress conditions. The influence of in situ stress on blasting stress wave propagation exhibits a critical distance. These research findings provide valuable insights for the safe and efficient extraction of deep, soft, high‐gas coal seams.
Zhang et al. (Wed,) studied this question.