Study on the superposition effect of stress waves and crack propagation law between blastholes at different angles

The drilling and blasting method is extensively employed in various industries such as mining and infrastructure construction. In the majority of blasting operations, strip-charges are predominantly utilized, while blastholes often exhibit an angled orientation in practical engineering scenarios. To investigate the stress wave superposition effect and the crack propagation law among blastholes at varying angles, this study employs a high-speed digital image correlation system to conduct blasting model experiments. The results indicate that: the fractal dimension of the crack propagation trajectory decreases progressively as the angle increases. the von Mises strain-time curve of the specimen initially increases and then decreases. As the angle between the blastholes widens, the fractal dimension of the crushing zone and blasting crack among the blast borehole decreases accordingly, suppressed the blasting effect of the blasted medium. On the central axis between the two holes, the stress superposition becomes more obvious in the direction away from the initiation point, and the peak value of strain is the highest at the bottom of the blastholes. When the angle between the blastholes is 30°, the strain in the specimen takes the longest to decline from peak to valley, and the blasting stress wave sustains its influence for an extended duration, thus maximizing the use of blasting energy. Conversely, when the angle between the blastholes is 0°, the specimen experiences the shortest duration of blasting action and the least efficient energy utilization.