The granite samples collected from the underground powerhouse of Pubugou Hydropower Station were tested on MTS815 Flex Test GT rock mechanics test system under uniaxial compression condition. During the whole test process, the acoustic emission events were monitored by PCI-2 based AE system. Based on the cylinder-covering spatial fractal model, the spatial distribution features of AE events and the changing law of spatial fractal dimensions at different stress levels were studied. The experimental results showed that there are little AE events at low stress stage. The AE events become gradually active as the stress increasing and the cumulative number of AE events raises exponentially when the stress is close to the peak strength. The fractal dimension values gradually decrease from 3 to 2 with the increase of stress and reach the minimum value when the loading is equal to the peak strength. At the later stage of elastic deformation, the spatial fractal dimension values decrease obviously with the microcracks in granite sample gathering in the nearby field of failure surface. The complexity of AE events spatial distribution can be characterized properly by its fractal dimension, and these results agree with the research results of rock burst in references.
