Abstract: Irregular columnar joints network models were firstly prepared by using the Voronoi diagram random simulation method and 3D printing technology. White cement slurries were chosen as the rock-like material and poured into the 3D printing irregular columnar joints network models. Then the single columns were removed from the 3D printing models, and the white latex and 502 glue were used to bond the single columns together. In doing this, the irregular columnar jointed rock mass specimens were obtained. Laboratory uniaxial compression tests were carried out on these specimens to investigate the strength and failure modes. The experimental results show that the changes in the uniaxial compressive strength against the dip angle β resembled a "J" shape trend, which indicates that the anisotropy of the uniaxial compressive strength is remarkable. Three typical failure modes are summarized, including splitting failure along the columnar joints, shear failure along the columnar joints and the axial compression failure along the single columns, and the failure patterns are somewhat different from those of the regular columnar jointed rock mass specimens. Furthermore, the experimental results in this study were compared with previous results with respect to the columnar jointed rock mass specimens bonded by pure cement slurry. The results show that the weaken effect of the columnar joints can be more adequately reflected using the specimens bonded by white latex and 502 glue than those bonded by cement slurry.

Key words: rock mechanics, irregular columnar jointed rock masses, model test, uniaxial compression test, failure mode