In the process of porous blasting excavation in engineering projects such as mining, hydropower stations, and tunnels, the delay time between adjacent blast holes significantly influences the characteristics of rock fracture and fragmentation. In order to visually explore the changing characteristics of strain and displacement between adjacent blast holes under different delay times, polymethyl methacrylate (PMMA) plates were used to simulate rock materials, and 2D digital image correlation (2D-DIC) testing methods were employed to measure the explosive strain field with different delay times (0 µs, 5 µs, 15 µs, 40 µs, 70 µs) for dual holes. Full-field principal strain cloud maps and displacement fields of PMMA boards in two-dimensional spatial coordinates were obtained, and the representative monitoring points were analyzed. The experimental results show that the maximum values of the first compressive principal strain peak and the first tensile principal strain peak at the connecting center of the two holes exist at a delay time of 0~40 µs under blasting conditions with the same hole distance and single hole charge. At the center point of the connection between the two holes, the interval time between the two principal strain peaks decreases with the increase in delay time. The maximum principal strain on the central vertical line of the connection line decreases exponentially with the increase in hole distance, and the attenuation trend increases first and then decreases with the delay time between 0 and 40 µs. At the peak of strain, the maximum average displacement of the connecting center of the two holes exists in the delay time between 0 and 40 µs. With the increase in delay time, the displacement trend between the two explosion holes gradually changes from shear to tension, and the vulnerable damage area increases, which makes the communication between the two explosion holes easier. This study can provide a basis for the precise selection of delay times between blasting holes in engineering.

Deep rock will be influenced by the excavation disturbances of different degrees, which seriously affects the safety production of underground mines. Considering that deep rock will be impacted by different temperatures and varied disturbance degrees, this work analyzes the effect of temperature on the dynamic properties of marble by means of the dynamic and static combined SHPB test device. The results reveal that as the temperature climbed, the diameter and height of the specimen increased and the mass and longitudinal wave velocity dropped. The variation laws of total stress–strain curves after varied high temperatures are substantially the same; the peak stress was negatively correlated with the action temperature. At 25 °C~400 °C, the failure mode of specimens is less affected by temperature. When the temperature is higher than 400 °C, the failure degree of specimens increases with the growth of temperature. At 25~400 °C, the above energy varies minimally. At 400~800 °C, with the increase in temperature, the incident energy, transmitted energy and absorption energy decrease, and the reflection energy increases gradually.

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.

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.