MESOSCALE STRUCTURE RECONSTRUCTION AND ANISOTROPIC BEHAVIOR MODELING OF LAYERED ROCK UNDER SPLITTING-TENSILE LOADING

Various meso-scale representations of layered rock are formed by the directional arrangement and cementation of the minerals on a layered structure, which is obviously anisotropic in the mechanical behavior. This study presents a meso-scale particle discrete element model, which can demonstrate the meso-scale structure of slate by introducing a spatial correlation function. Based on the derivation of mechanical parameters on the meso-scale, the numerical simulations for slate Brazilian splitting tests with different bedding angles (θ) are conducted to investigate the anisotropic behavior. The simulation shows that there are three typical failure modes due to the various arrangements of bedding structures, including tensile failure at θ ≤ 30°, combined shear and tensile failure at θ=45°~75°, and splitting-tensile failure at θ>75°. The splitting tensile strength and the fracture energy decrease with the increase of θ. The proposed method is able to describe the anisotropy characteristics and the deformation-fracture behavior for layered rocks, which is in a good agreement with corresponding experiments.