Calculating the time within which the emulsion explosive sensitized by gas microbubbles preserves the susceptibility to the initiating pulse

Abstract

Introduction. The paper considers the behaviour of the sensitizer, gas microbubbles (GMB). The matters of emulsion explosives (EE) reliable detonation in the course of blasting are addressed. Research objective. To improve the reliability of blasting operations that apply EE, the research aims to develop the procedure calculating the time within which a borehole descending charge of EE, sensitized by GMB preserves the ability to initiate. Methods of research are based on analytical research describing GMB deformation under the impact of hydrostatic pressure of the charge column as well as further motion of GMB in the pseudoplastic liquid. Results. It is known that with the sensitization of EE, GMB, with a decrease in total porosity below a certain critical value, EE lose the ability to initiate. In descending blast wells, under the influence of excessive hydrostatic pressure of the charge column, the size of the GMB decreases and the overall porosity of the EE decreases due to the compression of these microbubbles, which negatively affects the detonation capabilities of the EE. In this case, as shown in the article, after the formation of the borehole charge, an additional, slowly progressive decrease in the porosity of the EE occurs due to the ascent of the GMB. This contributes, after a certain period of time, to the loss of the ability to detonation decomposition by the downhole charge of the EE, which must be taken into account when the charge is in an explosive well for a long time. An analytical solution has been obtained that makes it possible to estimate the time of preservation by a borehole descending charge of EE, sensitized by GMB, the ability to initiate. The solution takes into account the heterogeneity of the GMB in size and the power of the intermediate detonator used to initiate the EE charge. Conclusions. The regularities obtained in the article make it possible to increase the reliability of blasting operations using EE, sensitized GMB.