## 3 Results
### Cumulative Infrasonic Energy Characteristics  
The variation in infrasonic cumulative energy reflects the cumulative process of damage in the loading process of rock specimens. In order to better reflect the change characteristics of rocks in the loading action of infrasound, infrasonic cumulative energy characterization is further carried out after the cumulative infrasonic energy rate is added. Figure 13 shows the infrasonic cumulative energy characteristics of the rock specimens under uniaxial compression, and the infrasonic cumulative energy before peak strength shows a significant dramatic increase. In the initial stage, the stress and strain of the rock specimens show a linear relationship, showing elastic deformation, and there is basically no damage or fracturing inside the rock specimens; the infrasonic cumulative energy grows slowly, and the infrasonic cumulative energy at point A is 0.1156 V\({}^{2}\). After point A, the growth rate of infrasonic cumulative energy increases significantly, and microfractures and damage began to appear inside the rock specimen. By point B, the infrasonic cumulative energy is 0.1375 V\({}^{2}\), and from point A to point B, the infrasonic energy increased by 0.0219 V\({}^{2}\). By point C, the infrasonic cumulative energy was 0.1658 V\({}^{2}\), and from point B to point C, the infrasonic energy increased by 0.0283 V\({}^{2}\). The infrasonic cumulative energy continues to increase, the number of fractures rapidly increases and propagates. The infrasonic cumulative energy is 0.1754 V\({}^{2}\) at point D. The infrasonic energy increases by 0.0096 V\({}^{2}\) from point C to point D. The infrasonic cumulative energy tends to stabilize or slightly increase, and the destruction of the rock specimens and the generation of fracture are essentially completed. Before peak strength, the infrasonic energy increases by a total of 0.0598 V\({}^{2}\) from point A to point D, indicating that there is a significant expansion and penetration of the internal fracture of the rock at this stage. The cumulative energy signature of infrasonic waves under cyclic loading and unloading can be similarly categorized into three stages, as shown in Figures 14 and 15. (1) The relatively stable period of infrasonic cumulative energy: During the low-stress period of the first and second cycles, the infrasonic cumulative energy increases slowly, and there is no obvious sudden change in infrasonic amplitude, which is due to the fact that during the compaction stage of the rock, the internal microfractures and micropores are compressed, and a small amount of new fractures is produced, which causes less damage. (2) The period of rapid growth of infrasonic cumulative energy: With the continuous strengthening of stress, the cumulative energy increases significantly, and the amplitude changes are obvious, especially when the peak stress is reached each time, the infrasonic cumulative energy increases significantly. The increment of the cumulative energy of the  
Figure 12: Characteristics of infrasonic energy rate under the cyclic loading and unloading of rock specimen A-4. rock specimens near point A is also significantly increased by 0.0067 V\({}^{2}\). The abnormal fluctuation of the infrasonic amplitude is significant in this stage, and a large number of new fractures are generated or expand inside the rock and the infrasonic activity starts to be active. (3) Destruction precursor period: In the high-stress stage of the fifth and sixth cycles; infrasonic activity is very active; the cumulative energy increment is the most significant; the cumulative energy increment of the rock specimens near point C is 0.1796 V\({}^{2}\), of which the cumulative energy increment is the largest near the point C of the upper stress limit of the fifth cycle; and the cumulative energy near points D and E is not significant but the amplitude appears to have very obvious fluctuations. Fractures rapidly expand, converge, and penetrate and the mechanical properties deteriorate sharply.