Jianguo Wang

Cemented backfill (CTB) in mining operations is frequently exposed to blasting-induced dynamic disturbances. These disturbances compromise CTB stability. This study employed split Hopkinson pressure bar (SHPB) tests, scanning electron microscopy (SEM), and high-speed imaging to characterize dynamic mechanical response and failure modes of CTB. The results showed that dynamic compressive strength (DCS) increased with impact load. However, damage severity also increased with load. High-speed imaging of crack evolution yielded fractal dimensions between 0.5 and 1.3. Higher fractal dimensions correlated with more extensive macroscopic cracking and greater CTB damage. They also indicated an increased probability of CTB failure and loss of load-bearing capacity. Microstructural observations identified ettringite (AFt) and C-S-H gel as the principal hydration products that provided cohesion and strength. However, pervasive microcracks and micropores accounted for the CTB’s low inherent strength. The findings suggest that reducing dynamic loads during mining operations can mitigate damage to CTB.

The drilling and blasting method remains fundamental to mining and tunneling projects, prized for its simplicity and economy. However, conventional techniques are increasingly challenged by modern safety and environmental standards, particularly in complex geological settings. Slotted charge blasting technology addresses these limitations by offering exceptional control over fracture propagation and damage. This paper provides a comprehensive review of the field, synthesizing global research on its theoretical foundations, advanced diagnostic methodologies, key performance parameters, and engineering applications. We critically analyze the current challenges facing the technology, particularly in weak rock conditions, where extensive plastic deformation and rapid energy dissipation often compromise directional control, and identify promising trends for its future development. Specifically, the integration of intelligent adaptive control and additive manufacturing is highlighted as a key direction. By mapping out a clear trajectory for future research, this work provides a scientific basis to advance the efficacy and safety of slotted charge blasting in demanding engineering environments.

Understanding the combined effects of water and dynamic disturbance on rock behavior is essential for deep underground engineering, where groundwater and blasting often coexist. Existing studies have mainly emphasized static weakening by water or the strength characteristics under impact, while the energy evolution process remains insufficiently addressed. To fill this gap, uniaxial impact compression tests were conducted on dry and water-saturated skarn specimens using a separated Split Hopkinson Pressure Bar system. The relationship between peak stress and impact pressure was analyzed, and the total input energy, releasable elastic strain energy, and dissipated energy were quantified to examine their evolution with strain. The results indicate that water saturation significantly reduces dynamic strength and modifies the damage process. During the compaction and elastic stages, dissipated energy is low but slightly higher in water-saturated specimens due to microcrack initiation. In the plastic stage, dry specimens exhibit faster energy dissipation, while water-saturated specimens show reduced capacity for crack propagation dissipation. Damage–strain curves follow an S-shaped pattern, with water-saturated specimens presenting higher damage growth rates in the plastic stage. These findings clarify the energy-based damage mechanisms of skarn under impact loading and provide theoretical support for evaluating stability in water-rich underground environments.