Damage prediction and improvement method based on cutting mode of circular empty hole

Area of Science:

• Rock mechanics
• Blasting engineering
• Geotechnical engineering

Background:

• The empty hole effect is crucial in cutting blasting.
• Understanding dynamic stress evolution and fracture mechanisms in rock masses is essential for optimizing blasting operations.

Purpose of the Study:

• To establish a 2D calculation model for dynamic stress evolution in hole walls.
• To predict dynamic fracture mechanisms and damage distribution in rock masses under longitudinal wave action.
• To compare the failure mechanisms and space utilization of circular versus square empty holes.

Main Methods:

• Integration of the Hopkinson effect and Saint-Venant principle to model dynamic stress.
• Development of a two-dimensional calculation model for hole wall stress.
• Experimental verification of calculation and numerical simulation results.
• Comparative analysis of circular and square empty hole models.

Main Results:

• Theoretical calculations align with simulation results, showing periodic dynamic stress evolution in circular cavities.
• Hole shape significantly influences rock mass failure: circular holes experience 'interval ring' destruction, while square holes exhibit extensive tensile and shear failure.
• Square empty holes offer 8.5 times greater space utilization than circular holes.
• Circular empty holes generate greater vibration effects with lower rock breaking energy proportion.

Conclusions:

• The shape of empty holes critically affects rock mass failure modes and space utilization in cutting blasting.
• Square empty holes are more effective in promoting rock mass failure and space utilization compared to circular holes.
• Further research into optimizing empty hole geometry for specific blasting applications is warranted.