Abstract
The distribution of discontinuities in the deep stratigraphic rock mass is random and irregular, and the spatial distribution has statistical self-similarity, which can be analyzed by fractal theory. The borehole wall image obtained based on the ultrasonic borehole imaging technology can clearly reflect the rich structural surface information such as the inclination, density, and crack width of the structural surface in the rock mass. Due to its inherent fractal characteristics, the fractal box dimension of the hole wall image can be used to describe the complexity of the structural surface. In the study, the fractal box dimension of the hole wall image and the RQD value of the rock mass are compared, and it is found that there is a linear correlation between the two. Therefore, the rock quality can be evaluated according to the fractal box dimension value of the hole wall image. Finally, a rapid quantitative evaluation method for rock mass quality classification is established based on ultrasonic borehole imaging technology and fractal method.
Highlights
As the depth of resource extraction increases, human engineering activities are gradually developing into the deep strata
RQD indicators are often used in evaluating rock quality indicators [5], which are widely used in rock mass stability evaluations such as water conservancy and hydropower, mines, underground engineering, and traffic engineering
E engineering background in this article is the exploration hole of the auxiliary shaft in the Xiling mining area of Sanshandao Gold Mine, and the hole depth is -2017 m. e ultrasonic borehole imaging test is mainly carried out for the deep formation, and the borehole wall images from the depth of −874 m and −1635 m are obtained. e quality of the rock wall in the deeper borehole is poor, and the probe is difficult to pass. e coring results for this drill hole show that the lithology is mainly granite, a kind of igneous rock
Summary
As the depth of resource extraction increases, human engineering activities are gradually developing into the deep strata. Advances in Materials Science and Engineering can be used to obtain intuitive and accurate information about the rock formation properties of the borehole wall, and the data of acoustic imaging, video, imaging, and geological data can be compared, and the high-precision information of the rock formations obtained by comprehensive interpretation can be made up for the missing data and information caused by the lack of core drilling [7]. Erefore, it is an important breakthrough to perform digital image processing on high-precision digital borehole wall images acquired by ultrasonic drilling imaging technology to accurately and quickly obtain rock quality characteristics in deep formations. The fractal method is used to analyze the hole wall image, and the correlation between the dimensional characteristics of the hole wall image box and the rock quality is studied, and a rapid and accurate rock quality analysis method based on borehole imaging technology is established [11]
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