Engineering formulas for dimensioning of deformation and damage zones in jointed rock mass under impact of blasting in quarries in Transbaikalia

Abstract

Currently, there are five characteristic zones of blast-induced impact in quarries: crushed zone, radial cracking zone, severely fractured zone, blast-induced residual stress zone, and blast-induced load zone. Knowledge about the size of the zones is very important in the technological processes of mining. The size of the crushed zone governs the amount of ore over-grinding and loss. The size of the radial cracking zone is reflective of the spacing of blastholes. The size of the severe fracturing zone is characteristic of the geometry of an unstable pit wall area. The zone of blast-induced residual stresses in rock mass and its size affects the slope stability of pit wall. The purpose of this study is to develop engineering formulas for calculating the sizes of deformation and damage zones in jointed rock mass during short-delay blasting in quarries. The mathematical and numerical analyses of the complex theoretical expression provided engineering formulas for dimensioning of the blasting-induced impact zones in quarries. The reliability of the formulas is proved by the comparison with the full-scale testing data obtained in quarries in Transbaikalia.