Numerical simulation of the damage behavior of Brazilian splits in deep shales

The fracture mode of deep shale determines the stability of engineering structures and the efficient development and use of energy. A three-dimensional numerical model of Brazilian splitting was used to investigate the relationship between shale texture characteristics and damage strength. The study analyzed the effects of texture angle and strength on shale damage pattern and tensile strength. The crack evolution process was accurately analyzed using acoustic emission distribution characteristics. The results indicate that the numerical simulation outcomes of Brazilian splitting agree with the experimental results. The cohesive element method can be used to predict the rock's damage behavior. The damage modes of shale specimens are classified into six categories under the coupling of the texture angle and the strength. For shale specimens with central damage, the acoustic emission energy-displacement curves are dominated by a single-peak distribution type. For specimens with mixed damage, including tension-shear mixed damage, the acoustic emission energy-displacement curves are dominated by a multiple-peak distribution type. The tensile strength of shale specimens is significantly anisotropic. The greater the texture strength and the closer the main crack is to the loading diameter direction, the higher the tensile strength of the specimens under the same texture angle. The results of the study also reveal the damage mechanism of shale and provide theoretical guidance for deep engineering applications.