孔内分层柱形装药下岩石试件爆破破坏特征OA

To improve the rock failure effects in open-pit deep hole blasting,a hole-inner layered column charge was designed.Firstly,small charge quantity blasting experiments under different charge forms were conducted to obtain the blasting failure pro-cess and final failure morphology of rock specimens.Then,the DEM-PBM(Discrete Element Method-Particle Blast Method)coupled simulation technique was used to numerically simulate the blasting process of various charges,further visually revealing the blasting failure characteristics of rock specimens.Finally,field tests were conducted to investigate the practical application ef-fects of this charge form.The results showed that under the blasting action of hole-inner continuous column charge,only one blasting crack occurs in the 1/4 section at the top of the rock specimen,dividing it into two parts.The horizontal moving velocity of the rock fragment is 2.0 m·s-1,and a large rock fragment with a diameter of 9.0 cm is produced after blasting.Under the the blasting action of hole-inner layered column charge,multiple blasting cracks occur in the 1/4 section at the top of the rock speci-men,dividing it into several fragments.The horizontal moving velocity of the rock fragment increase into 7.0 m·s-1,and no large fragments with a diameter of more than 5 cm is formed.Numerical simulations visualized the blasting process of rock speci-mens,and verified that the hole-inner layered column charge could eliminate large fragments with a size exceeding 5.0 cm.In practical open-pit deep hole bench blasting,the use of hole-inner layered column charge could significantly enhance the failure degree of rock mass at the top of bench,reducing the large rock fragment rate from 48.1%to 5.6%,which proved its engineer-ing practicality in improving rock failure effects of deep hole blasting.