Failure mechanisms of electronic detonators subjected to high impact loading in rock drilling and blasting

Abstract In rock drilling and blasting, the misfire of electronic detonators will not only affect the rock fragmentation result but also bring serious potential safety hazards to engineering construction. An accurate and comprehensive understanding of the failure mechanisms of electronic detonators subjected to impact loading is of great significance to the reliability design and field safety use of electronic detonators. The spatial distribution characteristics and failure modes of misfired electronic detonators under different application scenarios are statistically analysed. The results show that under high impact loads, electronic detonators will experience failure phenomena such as rupture of the fuse head, fracture of the bridge wire, falling off of the solder joint, chip module damage and insufficient initiation energy after deformation. The lack of impact resistance is the primary cause of misfire of electronic detonators. Combined with the underwater impact resistance test and the impact load test in the adjacent blasthole on site, the formulas of the impact failure probability of the electronic detonator under different stress‒strength distribution curves are deduced. The test and evaluation method of the impact resistance of electronic detonators based on stress‒strength interference theory is proposed. Furthermore, the impact failure model of electronic detonators considering the strength degradation effect under repeated random loads is established. On this basis, the failure mechanism of electronic detonators under different application environments, such as open-pit blasting and underground blasting, is revealed, which provides scientific theory and methods for the reliability analysis, design and type selection of electronic detonators in rock drilling and blasting.