Evaluation of the Consistency of Rock Joint Surface Morphology Based on Grayscale Surface-Differential Box Counting and Mechanical Tests

The accurate evaluation of the geometric morphology of rock and rock-like material joint surfaces was considered crucial for studying the mechanical properties of joint surfaces. A method based on grayscale surface and differential box-counting for evaluating the consistency of rock joint surface morphology was proposed in this study. The fractal dimensions of natural red sandstone joint surfaces and 3D printed restored joint surfaces were quantitatively identified. The consistency of the joint surface morphology of the samples was validated on both the image scale and the macroscopic mechanical scale using two approaches: CNN feature extraction and variable-angle shear tests. The validation results demonstrated a high degree of convergence, thereby confirming the accuracy of the proposed method. This study could provide a reference for the determination of the fractal dimension of joint surface morphology and the consistency research.