Abstract:Based on the phenomenon of loading condition sensitivity,which exists in the uniaxial compression tests of rocks,a numerical study is conducted to investigate the effect of loading conditions on the deformation behaviors and failure patterns of rocks with different sizes and shapes under uniaxial compression,using a self-developed numerical code EPCA2D. It is concluded that,for rocks with the same homogeneity,the size and shape effects are mainly caused by the mismatch of mechanical properties between rock specimen and loading platen. The simulation results agree with the experimental phenomenon well. Different friction conditions between loading platen and specimen¢s ends are considered in the simulation. Results indicate that the discreteness of uniaxial strength and deformation behaviours with different frictions exist even when the frictions are reduced to a very low value. Therefore,it is unfavourable to improve the experimental quality by reducing the frictions.