Experimental and Numerical Analysis of Fluid-Injection Unloading Rock Failure Process

The aim of this study is to investigate the mechanical responses and failure characteristics of fissured rock-like materials subjected to fluid injection unloading, using a combination of laboratory experiments and numerical simulations. A novel configuration of fissured rock-like specimens containing a single fluid-injection borehole has been fabricated in the laboratory to allow for simultaneous application of mechanical loads and internal fluid pressure. Advanced techniques, such as 3-D X-ray computed tomography and 3-D digital image reconstruction, have been utilized to examine the effects of initial unloading states on the morphological characteristics of internal fracture networks under coupled hydro-mechanical unloading conditions. Furthermore, a series of numerical simulations have been conducted to deepen our understanding of the fluid-injection unloading failure mechanisms.