Abstract: Numerical simulation method was used to explore the influence of in-situ stress on rock core discing under different stress combinations. The results showed that when the in-situ stress exceeds a certain value， rock core discing occurs. When the radial stress reaches 35MPa， rock core discing occurs， and the radial stress is the main factor that affects rock core discing， while the axial stress only leads to the partial failure on core surface. At the same radial stress， the core discing weakens with the increase of axial stress. The formation process of core discing is mainly dominated by shear failure， accompanied with a little tension failure. Rock core discing is a complex mechanical process.

Key words: rock core discing, radial stress, axial stress, shear failure, tension failure