TY - JOUR AU - Han, Juncheng AU - Tian, Mengting AU - Xiao, Weimin PY - 2026 TI - Numerical Test Research on the Dilatancy of Irregular Columnar Jointed Rock Mass under Unloading Condition JO - Chinese Journal of Underground Space and Engineering SN - 1673-0836 SP - 1272 EP - 1280 VL - 22 IS - 4 AB - In order to investigate the dilatancy of irregular columnar jointed rock masses (ICJRM) under unloading conditions, a series of three-dimensional discrete element numerical models of ICJRM with seven column dip angles were established, and the compressive strength typical failure characteristics and dilatancy evolution of ICJRM were obtained through numerical conventional triaxial compression tests under unloading confining pressure conditions. The results show that: The shape of peak deviatoric stress Δσ1f vs. dip angle βj curve resembled the letter “J”, where the peak deviatoric stress has the minimum value at βj =60°, and reached its maximum value at βj =90°, and the typical failure modes included splitting along the column and columnar joint surface, shear slipping along the columnar joint surface, and the compression-flexure destabilization of the columns; The dilatancy of irregular columnar jointed rock mass under unloading condition was closely related to the initial confining pressure and dip angle, and the corresponding volumetric strain increment obtained larger values when the dip angles ranged from 30° to 60° indicating a significant dilatancy. UR - https://doi.org/10.20174/j.JUSE.2026.04.16 DO - 10.20174/j.JUSE.2026.04.16