Influence of Water Content on Energy Partition and Release in Rock Failure: Implications for Water-Weakening on Rock-burst Proneness

As a common disaster in deep-buried hard rock engineering projects, rock-bursts seriously threaten the safety of workers and facilities. Water infusion in rock mass before excavation is usually used for rock-burst prevention. To reveal the underlying mechanism of rock watering for rock-burst inhibition, a series of uniaxial compression tests were carried out on sandstone samples with different water contents. The effects of water content on energy evolution characteristics (i.e., energy partition and energy release) were analyzed during loading process. In addition, a new rock-burst proneness criterion in terms of the release rate of post-peak energy was proposed to effectively evaluate the rock-burst proneness of water-bearing sandstone. The rock-burst proneness of samples with various water contents was calculated and compared. The experimental results have shown that with the increase of water content, the pre-peak strain energy density, elastic energy density, and dissipated energy density are decreased to some extents, as well as the rock-burst proneness. The water-induced reductions of the pre-peak elastic energy and the energy release rate during the post-peak phase collectively result in the decrease of rock-burst proneness of water-bearing sandstone.