# Research Progress on the Mechanisms and Control Methods of Rockbursts under Water-Rock Interactions
## 3 Research Progress on Water's Impact in Strain-Induced Rockburst Experiments
### The Weakening Effect of Water on Hard Rock and the Evolution of Internal Microcracks in the Rock  
Investigating how water reduces the strength of hard rock and influences the development of internal microcracks is a crucial area in rock mechanics research. Water infiltration leads to physical and chemical alterations in the rock, which impact its overall strength and stability [47, 48, 49, 50]. Furthermore, water can facilitate the growth and progression of internal microcracks, thereby influencing the mechanical properties of the rock [55]. To study how water promotes rock bursting through the relationship between energy dis  
Figure 3: Stress paths in true triaxial compression tests: (**a**) sample S17–17, (**b**) sample S17–29, (**c**) sample S29–17, (**d**) sample S29–29 ([PERSON] et al., 2018), (**e**) sample W17–17, (**f**) sample W17–29, (**g**) sample W29–17, and (**h**) sample W29–29 [28]. tribution and water content, [PERSON] et al. [55] explored the mechanical properties of hard sandstone samples at various moisture levels and investigated how moisture affects their brittleness. By integrating acoustic emission analysis, they tracked the development of microcracks in hard sandstone and examined how water influences rock brittleness from an energy-based perspective. Axial load tests conducted under varying restraining pressures and moisture levels revealed a significant impact of moisture on rock deformation as deviatoric stress increased. Higher moisture levels corresponded with reduced strain at peak stress, indicating a notable decrease in both the strength and stiffness of the rock. The data on [PERSON]'s modulus and peak strength further demonstrated that these values diminish as moisture content rises, with a Ks value closer to 1, reflecting a more pronounced weakening effect. Additionally, both lateral and volumetric strains after failure were reduced with increasing moisture. The triaxial compressive strength also declined with greater moisture content, underscoring the softening effect of moisture on sandstone. As moisture content increases, peak strength indicators (\(\sigma_{\text{cc}}\), \(\sigma_{\text{ci}}\), \(\sigma_{\text{cd}}\), and \(\sigma_{\text{f}}\)) decline, reflecting a decrease in the rock's load-bearing capacity. In contrast, when moisture levels are held constant, these strength parameters rise with increasing confining pressure, as the pressure helps to prevent rock failure. Additionally, the accumulation of total energy slows as moisture content rises, a critical factor in using water to reduce rock bursts. The rate of elastic strain energy accumulation during the energy storage phase also decreases with higher moisture levels. The rock's energy storage capacity, represented by residual elastic strain energy (RESE), shows a clear linear decline as moisture content increases. However, greater confining pressure enhances the rock's ability to store energy. The energy storage and release mechanism of rocks mainly involves the accumulation and dissipation of strain energy. Uniaxial compression tests show that rocks follow linear energy storage and dissipation laws during loading, i.e., the input strain energy, elastic strain energy, and dissipated strain energy are linearly related to the square of the stress at different unloading points. The energy storage potential includes relative and ultimate energy storage potentials, while the energy release potential reflects the extent of energy release when the rock reaches the damage threshold. The presence of water can seriously affect the microstructural integrity of rocks. Moisture weakens the microstructure of rocks, increases porosity, and reduces bond strength, thus reducing the strength and hardness of rocks. The deterioration of the microstructure directly affects the stress distribution within the rock mass, reducing its energy storage capacity and intensifying the dissipation process.