Dynamic interaction of borehole charges groups in time and its effect on the explosive destruction of a rock mass

Abstract

Purpose. The main objective of the research is to determine the time factors that affect the destruction of rocks under the action of their short-delayed detonation. And dedicated to the solution of the current issue - to reduce the specific costs of explosives for rock crushing by changing the order of work. At the same time, the condition of the rocks destroyed by the explosion is taken into account. The research methodology includes analytical calculations on explosion physics, geomechanical analysis of dynamic destruction of rocks; substantiation of the mathematical model of the tensions distribution and deformations in the crystalline rock and mathematical methods of processing the results of experimental and industrial tests. Findings. Peculiarities and conditions of implementation of balanced blasting of rock massifs with combined borehole charges of modern explosives in an iron out-pit have been investigated. With the use of mathematical modeling, the dependence of the values of the deceleration intervals of groups of borehole charges on the physical and mechanical characteristics of the rocks, taking into account the size of the granulation, was obtained. The originality. The scientific originaliy of the research consists in revealing the patterns of the formation and dissemination of blast wave fronts during the interaction of borehole charges of the author's design (with a differentiated distribution according to the length of the boreholes and the ratio of the masses of their dispersed parts), which are detonated in one series. Specifically, the development of the theory of explosive destruction of rocks consists in establishing the time dependence of the moments of successive detonation of charges in the borehole group from the superposition of the maximum of positive phases in their fronts, which ensures the explosion of the next charge at precisely such a moment to maximize the formation of cracks in the surrounding material. Practical implementation. The practical significance of the research lies in the development of a new effective method of rock blasting in the conditions of open-pit mining, as well as in the substantiation of the technological parameters of the method, which reduces the specific consumption of explosive materials and increases the quality of the iron ore enrichment works production