Digital reconstruction of three-dimensional contours and its application to microstructural evaluation of postblast rock fissure surfaces

Abstract

Fracture surface contour study is one of the important requirements for characterization and evaluation of the microstructure of rocks. Based on the improved cube covering method and the 3D contour digital reconstruction model, this study proposes a quantitative microstructure characterization method combining the roughness evaluation index and the 3D fractal dimension to study the change rule of the fracture surface morphology after blasting. This method was applied and validated in the study of the fracture microstructure of the rock after blasting. The results show that the fracture morphology characteristics of the 3D contour digital reconstruction model have good correlation with the changes of the blasting action. The undulation rate of the three-dimensional surface profile of the rock is more prone to dramatic rise and dramatic fall morphology. In terms of tilting trend, the tilting direction also shows gradual disorder, with the tilting angle increasing correspondingly. All the roughness evaluation indexes of the rock fissure surface after blasting show a linear and gradually increasing trend as the distance to the bursting center increases; the difference between the two-dimensional roughness evaluation indexes and the three-dimensional ones of the same micro-area rock samples also becomes increasingly larger, among which the three-dimensional fissure roughness coefficient JRC and the surface roughness ratio R_s display better correlation. Compared with the linear fitting formula of the power function relationship, the three-dimensional fractal dimension of the postblast fissure surface is fitted with the values of JRC and R_s, which renders higher correlation coefficients, and the degree of linear fitting of JRC to the three-dimensional fractal dimension is higher. The fractal characteristics of the blast-affected region form a unity with the three-dimensional roughness evaluation of the fissure surface.