Fracture characteristics of iron ore under uncoupled blast loading

作者

Jinjing Zuo Renshu Yang Min Gong Xinmin Ma Yanbing Wang
单位

School of Civil and Resource Engineering, University of Science and Technology Beijing State Key Laboratory for Geomechanics and Deep Underground Engineering （Beijing） School of Mechanics and Civil Engineering, China University of Mining and Technology-Beijing
摘要

A blasting experiment was conducted on iron ore samples by considering multiple coupling charge coefficients. The resulting internal fracture and damage characteristics were quantitatively analyzed via computerized tomography(CT), scanning, and three-dimensional(3D) model reconstruction. The results show that the iron ore primarily displayed radial and circumferential cracks along the blast hole under an explosive load. When the decoupling coefficient was small, the crack surface was dominated by transgranular fractures in the form of intracrystalline fractures. As the uncoupling coefficient increased, the crack surface exhibited transgranular and intergranular coupled fracture modes. Using fractal theory to analyze crack distribution characteristics, as the decoupled coefficient increased, the body fractal dimension tended to decrease, and the degree of damage gradually decreased. The degree of damage reached a turning point when the decoupling charge coefficient was approximately 1.33. A numerical simulation suggested that the explosion energy transmitted to the iron ore and the effective stress decrease sharply when the decoupling coefficient exceeds 1.33. In some optimal uncoupling coefficient range, excessive fragmentation of the ore body is prevented, thereby allowing full use of the explosive energy.
基金项目(Foundation)

supportedbyChinaPostdoctoralScienceFoundation(No.2020TQ0032)；theKeyProjectsofNationalNaturalScienceFoundationofChina(No.51934001)；theFundamentalResearchFundsfortheCentralUniversities(FRF-TP-20-037A1)；theInterdisciplinaryResearchProjectforYoungTeachersofUSTB(FundamentalResearchFundsfortheCentralUniversities)(FRF-IDRY-20-019)；
文章目录

1. Introduction
2. Specimen processing
3. Effects of uncoupled charging on the iron ore failure law
3.1. Iron ore fracture surface under uncoupled charging
3.2. CT scanning and 3D reconstruction of iron ore
3.3. Fractal dimensions of a radial uncoupled 3D body
3.4. Relationship between decoupled coefficient and blasting action
4. Conclusions
引用格式

Jinjing Zuo,Renshu Yang,Min Gong,Xinmin Ma,Yanbing Wang.Fracture characteristics of iron ore under uncoupled blast loading[J].International Journal of Mining Science and Technology,2022,32(04):657-667.