Study on damage characteristics of blasthole surrounding rock under high temperature

The shock damage of brittle rock under high temperature generally reflects its cracking characteristics, which is of significance in practical engineering of dry hot rock energy resources. In this paper, the parameters of the HJC constitutive model that can reflect the temperature effect are obtained by simulating the granite failure process with Hopkinson pressure bar under different temperatures. For a single blasthole, the granite damage and cracking characteristics under different temperatures are studied. The results indicate that the crush area around the blasthole is not sensitive to temperature changes under the blasting loading while the crack area increases substantially under 100℃ temperature but changes little between 100℃ and 500℃. Then keeping the blasting load peak(1 500 MPa) unchanged, the increase of loading rate has a great influence on the crack area at room temperature but a negligible influence at high temperature. And the increase of explosion load impulse or the action time can result in the expansion of crack area obviously, especially at a high temperature between 100℃ and 500℃. Therefore, to reduce the crush area and increase the crack area of surrounding rock during the dry hot rock cracking process, the low-detonation-velocity explosive is suggested to use for controlling the crush area. And raising the charge weight correspondingly to increase the load action time can increase the crack area for better cracking effect. Although the high ground temperature can affect the impact property, cracking effect induced by explosion will be enhanced. © 2020, Science Press. All right reserved.