Abstract
•Internal cracks are constructed by CT scanning and 3D reconstruction.•The same conclusion can be drawn by analyzing internal and surface cracks.•Failure mode is governed by joint angle, but persistence and filling show no effect.•Specimen strength and failure feature are affected by joint persistence.
The distribution of joints in rock masses is complex and diverse, existing in a three-dimensional (3D) state within the rock mass. And the destruction of rock also occurs under 3D conditions. This study utilizes computed tomography (CT) scanning, 3D reconstruction via Avizo software, and fractal dimension analysis to quantitatively characterize and qualitatively analyze the fracture surfaces and internal cracks of rock-like specimens containing 3D non-persistent joints under uniaxial compression. The aim is to investigate the failure characteristics of jointed rock-like masses and the influence of the geometric parameters (angle α and persistence λ) of 3D non-persistent joints on these characteristics. The trial results and conclusions obtained are as follows: (1) The joint inclination angle primarily controls the failure mode: the specimens exhibit compression-shear composite failure at α = 30°, shear-dominated failure at α = 45° and 60°, and tensile splitting failure at α = 90°, whereas joint persistence mainly affects strength and post-peak characteristics. (2) CT-based quantitative analysis shows that fracture volume (FV), fracture surface area (FS), and the 3D fractal dimension exhibit similar variation trends: they first decrease and then increase with increasing α, while first increasing and then decreasing with increasing λ. These consistent trends indicate a certain association among the three parameters in characterizing fracture features. The results provide an experimental basis for understanding the 3D failure behavior of 3D non-persistent jointed rock-like materials under uniaxial loading.