Analysis of Energy Dissipation and Failure Law of Gabbro under Cyclic Dynamic Load

In order to study the damage law and failure mode of pegmatite gabbro under cyclic loading, the Split Hopkinson Pressure Bar (SHPB) and PFC3D numerical simulation software were used to carry out cyclic impact tests of pegmatite gabbro at different impact velocities, and the damage characteristics and failure law were analyzed. The results show that: Under low impact velocity, the original cracks of the rock specimen are first compacted and then gradually destroyed with the increase of the number of cycles, and the dynamic compressive strength of the rock specimen increases first and then decreases gradually. With the increase of the number of cycles, the proportion of rock reflection energy and energy consumption density generally show an upward trend, and the proportion of transmission energy generally shows a downward trend. The damage variable of the rock specimen first shows a negative growth and then a steady growth, and the damage variable of the specimen increases rapidly before the macroscopic failure occurs. Under high impact velocity, the rock specimen will be destroyed in each cycle, the dynamic compressive strength of the specimen increases with the increase of the number of cycles, and the damage variable of the specimen also increases with the increase of the number of cycles. The failure process of the specimen under cyclic loading was simulated by PFC3D, and it was found that the rock specimen was always destroyed along the longitudinal plane under cyclic loading.