Stress–Seepage Coupling of Cataclastic Rock Masses Based on Digital Image Technologies

To explore the mechanical properties of cataclastic rock masses and the laws of their permeability changes under hydraulic pressure, cataclastic rock masses in shattered fault zones are sorted according to their particle size. Rubble is sorted under the same conditions to acquire digital images in sections and extract spatial distribution information. Due to significant numerical differences between rocks and pores in pixel functions and image matrices, MATLAB functions are developed for threshold segmentation. Using linear interpolation, three-dimensional digital analysis models are built. Based on these models, interconnected networks of spatial structures and spatial distribution features of stress, seepage and speed are identified for cataclastic rock masses. The seepage flow of cataclastic rock masses is approximated based on the maximum and minimum particle sizes. Additionally, an experimental study is performed with a seepage tester on cataclastic rock masses. According to the results, the impacts of the particle size on seepage differ significantly under different stress conditions. The seepage flow curve determined from the experiment is within the hydraulic pressure flow scope determined based on the maximum and minimum particle sizes. The seepage is in line with Forchheimer’s equations, but sharply contrasts with the theoretical results of Darcy’s law. This simulation method can be used as a reference for studying seepage–stress coupling of cataclastic rock masses.