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HYDRODYNAMICS AND ACOUSTICS
2021 ◊ Volume 2 (92) ◊ Issue 1 ◊ p. 5-12
V. V. Boiko*, A. A. Kuzmenko*, O. M. Chala*, D. V. Hlevnyuk*
* Institute of Hydromechanics of NAS of Ukraine, Kyiv, Ukraine
On the actual number of the simultaneously blown-up borehole charges
Gidrodin. akust. 2021, 2(1):005-012
TEXT LANGUAGE: Russian
ABSTRACT
Explosive work in industry, including mining in the extraction of minerals, is carried out mainly with borehole charges. In doing so, a systemic division of the explosion block into separate groups is provided. Each group consists of individual borehole charges and is a set of dispersed ones. The groups explode according to the scheme of short-delayed blasting at certain intervals of at least 20 ms. The seismic effect of such an explosion is determined by the formula of lumped charge. The dispersed charges are effectively used when driving trenches in mining, forming screens and cracks near protected objects. Only this blasting method provides an evaluation of the seismic effect when switching from one charge diameter to another. Moreover, one can determine the detonated number of charges in one group, which may differ from that calculated in the drilling and blasting project. The article discusses the physical essence of the processes accompanying the simultaneous detonation of dispersed charges. The effect of the directionality of the seismic impact of an explosion of dispersed charges relative to the line of their location is studied. The results of experimental studying of seismic action of short-delayed mass explosions in quarries are analyzed. These data are obtained when exploding the dispersed charges. Based on them, a technique was developed to determine the practical numbers of the simultaneously exploded borehole charges that are not provided for by the passport of a mass explosion. At the same time, in parallel with the mass explosion, the single borehole charge is exploded. The proposed method allows for realistic determining the seismic effect of mass explosions on protected objects and practical recommendations on this issue.
KEY WORDS
earthquake velocity, seismicity factor, detonator response time, wellbore charge, mass explosion, effective charge weight, number of charges