Energy dissipation of rock specimens under high strain rate with single joint in SHPB tensile tests

The energy dissipation in single jointed rocks under high strain rate is investigated by the split-Hopkinson pressure bar (SHPB) technique. The dynamic split tensile tests on both intact granite specimens and man-made single jointed granite specimens with a thickness-diameter ratio of 0.5 are carried out. The compressive analysis on the temporal responses of incident energy, reflection energy, transmission energy and absorbed energy stored in the rock specimens is performed. The anisotropy characteristics of energy dissipation of the jointed rock are discussed based on the analysis of energy distribution. The results show that the absorbed energy of rock specimens in SHPB tests increases with the increment of strain rate. The fracture modes of jointed granite with different angles are different from each other. There are three kinds of fracture modes: sliding failure along the joint, combination of splitting failure and slide failure, and splitting failure. When the incident energy stays constant, the absorbed energy with shorter incident time is less than that with longer incident time. The distribution of absorbed energy corresponding to the joint angle within range of 0, 90° is found to be quite similar with the shape of letter “U”, which further proves the anisotropic characteristics of the single jointed rock in the dynamic split tensile tests. The research results can provide references for the dynamic tensile mechanical properties of jointed rock.