A validated particle flow code (PFC2D)-based model was developed to investigate the indirect tensile mechanical behavior of shale containing two central parallel cracks under Brazilian splitting test conditions.The results show that preexisting cracks have a significant and insignificant influence on the tensile strength of shale under LPL and LVL conditions,respectively.When L ≥ 10 mm,changing the L and H values has little effect on the tensile strength of shale.However,the inclusion of preexisting cracks have a positive effect on reducing the anisotropy of the shale specimens,and in the case of an L/D ratio of 0.3,the shale anisotropy is the lowest.Four failure modes were formed at different β and θ values under LPL conditions.In the case of β≥ 60°,the failure mode is mainly affected by β,and when β ≤ 45 °,the failure mode is more complicated than in the case of β≥ 60°.Only three major failure modes were observed under LVL conditions;in the case of 45°≤β≤75° and θ≤30°,the most complex failure mode occurred.