Mechanism of iron ore blasting fracture using axial uncoupled charges  

作　　者：Yuanyuan You Renshu Yang Jinjing Zuo Zhen Yang Jin Li Yong Zhao Haibao Yi 

机构地区：[1]School of Mechanics and Civil Engineering,China University of Mining and Technology-Bejing,Beijing 100083,China [2]School of Resources and Safety Engineering,University of Science and Technology Beijing,Beijing 100083,China

出　　处：《International Journal of Minerals,Metallurgy and Materials》2025年第4期788-801,共14页矿物冶金与材料学报(英文版)

基　　金：financially supported by the National Natural Science Foundation of China (No. 52227805);the Fundamental Research Funds for the Central Universities (Ph.D. Top Innovative Talents Fund of China University of Mining and Technology Beijing) (No. BBJ2024085);the National Natural Science Foundation of China (Nos. 52474026 and 52208384)。

摘　　要：The axial uncoupling coefficient and air deck effect in blasting significantly influence the effectiveness of rock fragmentation.This study employs a passive confinement device to conduct continuous charge and five different axial uncoupling coefficient blasting ex-periments on cylindrical iron ore samples to explain the rock-breaking mechanisms associated with various axial uncoupling coefficientsand air deck effects. It utilizes advanced techniques such as computer tomography(CT) scanning, deep learning, and three dimensional(3D) model reconstruction, to generate a 3D reconstruction model of “rock explosion cracks” under varying axial uncoupling coefficients.This model illustrates the spatial distribution and configurations of explosion cracks. Integrating box-counting dimension and fractal di-mension theories enables the quantitative analysis of the three-dimensional fracture field and the extent of damage in rocks subjected toexplosive forces. Laboratory 3D experimental results indicate that continuous charging produces the most extensive damage, while a un-coupling coefficient of 1.50(case 1) results in the least. A moderate air deck length enhances blasting effectiveness and rock fragmenta-tion. For identical charge quantities. In contrast, increasing the charge amount with a constant air deck length further augments rock frag-mentation. A rock blasting calculation model was developed using LS-DYNA numerical simulation software under various axial uncoup-ling coefficients. This model depicts the dynamic damage evolution characteristics of the rocks and variations in hole wall pressure. Thenumerical simulation results of cumulative rock damage align with the laboratory findings. In addition, increasing the air deck length re-duces the peak of the explosion shock wave, decreasing the peak pressure in the charge and air sections by 37.8% to 66.3%. These re-search outcomes provide valuable theoretical support for designing and optimizing axial uncoupling coefficients in practical applications.

关 键 词：computer tomography BLASTING charge structure 3D reconstruction DAMAGE 

分 类 号：TD2[矿业工程—矿井建设]