Abstract: Through analyzing the existing definitions of damage variables, we try to use the fractal dimension as a characteristic of the rock damage variable and establish the relationship between fractal dimension and damage degree. According to the calculation method of box-counting dimension and digital image storage principles, to compile the simple digital image of a box-counting dimension algorithm based on Matlab. Combining with practical project of blasting, the digital panoramic borehole camera system is taken for field-test. Through extracting the crack from images of the before explosion and post-explosion of blasts rock, then some graphics processings are made to get the fractal dimensions corresponding to cracks. Finally, damage increments under the action of blasting are determined. The results show that the using fractal dimension to describe the damage of rock, overcomes the disadvantages of other definition methods which involve too much rock characteristic parameters, so as to explore a new way to study the damage degree and evolution process of rock damage.

Key words: blasting loading, damage variable, fractal dimension, crack