The failure process of high stress rock with through-water disturbance based on acoustic emission

Abstract

In the process of deep engineering excavation, the mechanical properties of rock are significantly influenced by the coupled effects of water and high stress, which greatly increase construction difficulty. To more accurately investigate the impact of water disturbance on the failure process of dry rock under high stress and the failure mechanisms of saturated rock in underwater environments, a water environment test chamber and a prefabricated borehole specimen through-water device were designed. A series of experiments were conducted, including uniaxial tests, water-disturbed granite cylinder tests, and through-water disturbance tests on prefabricated hole square specimens. The results showed that the acoustic emission (AE) hits and accumulated energy after the through-water disturbance at the same time were 8.77 and 12.08 times higher than before the disturbance, respectively. And water disturbance increased the proportion of tensile failure and reduced the proportion of shear failure. A key observation was that AE events were mainly generated in the permeation areas near the borehole. The main reason was that under high stress, the weakening effect of water led to the failure of the local mineral structure of the rock, promoting crack extension and triggering overall instability. Notably, failure of the saturated specimens underwater was only observed when the applied load approached the saturation strength of the prefabricated hole square specimens. The study results provide an important theoretical basis for understanding the damage mechanism of water-disturbed rocks in deep engineering, and have significant implications for the design and construction of engineering.