Explosive Preparation of Rocks in Career with Well Retarders

Abstract

The article deals with improving the quality of fragmentation of rocks by blast due to increase in intervals of delay. It shows the change in understanding of the mechanism of rock destruction under the influence of blast loads in recent decades. The mechanical effect of blast loads is manifested not only in crushing of rocks, but also in the weakening of their strength in remote distances from a charge. In the area of the blast wave compressive and tensile loads lead to the development of existing micro-defects and micro-cracks. The rock mass changes its strength properties, passes into a new state, called pre-destruction. The increase of delay time between blasts of charges increases the overall time of the blast, contributes to the merging of cracks and a gradual decrease in the sizes of the structural elements of the rocks. Impact on rocks alternating loads up to 20 or more times allows to increase the distance between the charges.