The objective of this study was to investigate the effects of axial static stress, confining pressure, strain rate on the energy dissipation and failure patterns of granite under three-dimensional coupled static-dynamic loading on a modified split Hopkinson pressure bar (SHPB) system. In particular, four levels of axial static stress (25, 50, 75 and 100 MPa), four levels of confining pressure (0, 5, 10 and 15 MPa) and four levels of strain rate (70, 90, 110, 130 s-1) were respectively set up. The test results showed that the absorbed energy per unit volume increased with the decreasing axial static stress, growing confining pressure and higher strain rate. Moreover, it was found that energy storage limit (ESL) played vital roles in the process of energy absorption and release in various situations during the impact: the difference between ESL and initial energy determined the energy absorption value; the ratio between them derived the energy release value when the rock entered early damage stage under static stresses. ESL itself, on the other hand, was proportional to the energy release value when the rock turned into late damage stage before dynamic loading. In addition, the destructiveness had a close correlation with energy dissipation: such a correlation maintained negative when the strain rates were similar and static stress combinations varied; it turned to be positive when static stress combinations were fixed and strain rates varied.
