In order to extract the mineral resources existing at great depths, the mining industry is facing new serious challenges to safe and productive mine operation, and such challenges arise largely as a result of the high pressures imposed on deep mine excavations. In order to investigate the effect of confinement on rock fracturing under dynamic loads, blasting experiments by using cement mortar plates, which are square with a single centralized borehole, have been carried out. Two kinds of confinement, i.e. uniaxial and biaxial, are applied to the square plates. In the study of defect effect, circular cement mortar plates with randomly distributed defects are employed, the results show that confinement and defects affect rock fracturing significantly.