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Yuanyuan You, Renshu Yang, Jinjing Zuo, Zhen Yang, Jin Li, Yong Zhao, and Haibao Yi, Mechanism of iron ore blasting fracture using axial uncoupled charges, Int. J. Miner. Metall. Mater., 32(2025), No. 4, pp.788-801. https://dx.doi.org/10.1007/s12613-024-3038-x
Yuanyuan You, Renshu Yang, Jinjing Zuo, Zhen Yang, Jin Li, Yong Zhao, and Haibao Yi, Mechanism of iron ore blasting fracture using axial uncoupled charges, Int. J. Miner. Metall. Mater., 32(2025), No. 4, pp.788-801. https://dx.doi.org/10.1007/s12613-024-3038-x
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轴向不耦合装药下铁矿石爆破断裂机理

摘要: 爆破中轴向不耦合系数和空气间隔效应对铁矿石破碎效用具有显著影响。为了揭示轴向不耦合系数和空气间隔效应下的爆破破岩机制,本研究利用被动围压装置,对铁矿石圆柱试样开展了连续装药和5种轴向不耦合系数下的爆破加载实验。通过计算机断层CT扫描、深度学习和三维重建技术,构建了轴向不耦合系数下受爆破作用的“铁矿石—爆炸裂纹”三维重构模型,直观展示了爆炸裂纹的空间分布及其位置与形态。结合计盒维数体分形维数理论,定量分析了铁矿石在爆炸作用下的三维裂隙场与损伤程度。实验结果表明,连续装药的损伤度最大,而轴向不耦合系数为1.50(case1)损伤程度最小。在药量相同的条件下,适度增加空气间隔长度可增强爆破破岩效用;在空气间隔长度相同的条件下,适当增加药量也能提高铁矿石的破碎程度。通过LS-DYAN数值模拟软件建立了轴向不耦合系数下的铁矿石爆破计算模型,捕获了铁矿石的动态损伤演化特征及孔壁压力变化特性,且铁矿石累积损伤数值计算结果与实验室实验结果一致。此外,增加空气间隔长度可以使爆炸冲击波的波峰变缓,装药段和空气段压力峰值降低37.8%~66.3%。研究成果可为现场轴向不耦合系数设计及优化提供了理论支持。

 

Mechanism of iron ore blasting fracture using axial uncoupled charges

Abstract: 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 experiments on cylindrical iron ore samples to explain the rock-breaking mechanisms associated with various axial uncoupling coefficients and 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 dimension theories enables the quantitative analysis of the three-dimensional fracture field and the extent of damage in rocks subjected to explosive forces. Laboratory 3D experimental results indicate that continuous charging produces the most extensive damage, while a uncoupling coefficient of 1.50 (case 1) results in the least. A moderate air deck length enhances blasting effectiveness and rock fragmentation. For identical charge quantities. In contrast, increasing the charge amount with a constant air deck length further augments rock fragmentation. A rock blasting calculation model was developed using LS-DYNA numerical simulation software under various axial uncoupling coefficients. This model depicts the dynamic damage evolution characteristics of the rocks and variations in hole wall pressure. The numerical simulation results of cumulative rock damage align with the laboratory findings. In addition, increasing the air deck length reduces the peak of the explosion shock wave, decreasing the peak pressure in the charge and air sections by 37.8% to 66.3%. These research outcomes provide valuable theoretical support for designing and optimizing axial uncoupling coefficients in practical applications.

 

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