Fractal study of media damage under blasting loading

Based on the calculation theory of box-counting dimension,a calculation method to calculate the fractal di- mension of blast-induced cracks is proposed,and the relationship between fractal dimension and damage degree by blasting is established. A box-counting dimension algorithm based on digital image is compiled using Matlab software. The fractal character of blast-induced cracks under both ordinary charge blasting and slit charge blasting is analyzed u- sing the boxing-counting dimension algorithm,and the damage degree of different regions around borehole is deter- mined. The results show that,in ordinary charge blasting,the damage degree induced by blasting reduced with crack propagation,but almost the same in same regions away from the borehole. In slit charge blasting,the damage degree of blast media presents a significant regional and orientated character,in region I,compared to the ordinary charge blas- ting,the damage degree induced by blasting along the slit direction slightly decreased,which reduced significantly in non-slit direction. In region II,the damage degree induced by blasting along the slit direction increased compared to the same region in ordinary charge blasting,while the damage degree decreased in non-slit direction. In region III,the damage degree along the slit direction increased significantly,while it decreased in non-slit direction. The calculation of damage degree induced by blasting based on fractal dimension can be used to quantitatively evaluate the spatial dis- tribution characteristics of blast-induced cracks,so as to explore a new way to study the evaluation law of damage de- gree induced by rock blasting.