A blasting experiment was conducted on iron ore samples by considering multiple coupling charge coef-ficients.The resulting internal fracture and damage characteristics were quantitatively analyzed via com-puterized 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 trans-granular 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 dimen-sion 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.

School of Civil and Resource Engineering,University of Science and Technology Beijing,Beijing 100083,China;State Key Laboratory for Geomechanics and Deep Underground Engineering(Beijing),Beijing 100083,China;School of Mechanics and Civil Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China

[1]Jinjing Zuo;Renshu Yang;Min Gong;Xinmin Ma;Yanbing Wang-.Fracture characteristics of iron ore under uncoupled blast loading)[J].矿业科学技术学报（英文版）,2022(04):657-667

ficients,puterized,intracrystalline

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