Method of numerical modeling in the problems of predicting the effect from air gap in blasthole charge design

Abstract

Introduction. The article presents the results of numerical modeling of the effect made the air gap in the borehole charge design on the seismic impact of blasting, base work and the stemming ejection speed. Intensification of mining drives the need for the design of blasting operations with a gentle impact on the rock mass while maintaining the required quality of the explosion. The assessment of the major blast impact on a rock mass may include both the results of collecting statistical observational data in specific mining and technological conditions, and the results of numerical modeling of crush zone formation, seismic impact, and the speed of stemming ejection during a major blast. Numerical modeling allows not only to make a preliminary forecast, but also to conduct a series of computational experiments to select the appropriate parameters of drilling and blasting operations in order to achieve the expected effect. The position and size of the air gap in the borehole charge are considered as such a parameter Research methods. The work uses an integrated method combining analysis, scientific generalization of theoretical and experimental studies relating to air gap in borehole charges, and the use of numerical modeling tools and digital technologies in mining. To simulate the action of an air gap during an explosion with expandable and destructible rock mass walls, a software package was used, consisting of the ANSYS AUTODYN software package, which has proven itself in solving non-stationary problems of nonlinear dynamics, and the software package developed by the members of the Institute of Communications and Information Technologies of the Kyrgyz-Russian Slavic University, to assess the stress-strain state of rocks using parallel computing technology. Results. Gas-dynamic processes relating to air gap were analyzed by the method of numerical simulation; the crush zone was estimated. The simulation tool was adjusted and calibrated based on numerical simulation results comparison with the results of laboratory studies of the air gap effect in wells during an explosion in organic glass. Satisfactory convergence of the results made it possible to use this tool for modeling explosive loading in conditions close to industrial scales. Discussion. The modeling performed allows us to state that the bottom work, the reduction in the stemming ejection speed and in the seismic impact are achieved through the use of an air gap and a reduced proportion of explosive. Thus, the use of numerical simulation techniques in mining problems to solve a wide range of production problems to optimize the charge design is justified. Scope of results. The results are relevant for the problems of optimizing drilling and blasting operations in the mining industry in order to ensure a gentle effect of blast on the environment