Abstract: Based on the geological structure of columnar jointed rock mass, artificial columnar jointed rock mass specimens with different column dip angles and transverse joints were made of cement mortar. Uniaxial compression tests were carried out to investigate the effect of dip angles and transverse joints on mechanical behaviour and failure modes. The results showed that the shape of various curves of deformation modulus and peak strength with dip angles were similar to the letter “U” which indicated significant anisotropy. With the dip angles changed, the failure modes of columnar jointed rock mass under uniaxial compression would be different. Four typical failure modes were summarised, i.e., the splitting failure orthogonal to column axis, shear-sliding failure, comprehensive failure of splitting and shear-sliding, splitting failure along the column axis. Since the transverse joints cut off columns, the integrity of rock mass was reduced along the axial direction, which influenced the distribution and coalescence of splitting fracture. Thus, the bearing capacity of columnar jointed rock mass was largely affected by the transverse joints.

Key words: columnar jointed rock mass, transverse joints, anisotropy, failure mode, uniaxial compression test