Preliminary study on transparent analysis of continuous evolution of mining-induced stress fields in surrounding rocks of faulted roadway

The variation of stress fields in faulted surrounding rock structures induced by mining disturbance is the fundamental cause of fault-type rock burst. Visually describing and quantitatively characterizing the continuous evolution of mining-induced stress fields in such structures is crucial for revealing the mechanism of fault-induced rock burst and achieving effective source control and prevention. In this study, high-precision transparent physical models of faulted surrounding rock structures were fabricated using 3D printing technology and stress-sensitive photoelastic materials. A self-developed transparent analysis experimental system for mining-induced stress fields in surrounding rocks of mine roadway was employed to capture the continuous full-field stress evolution within the faulted rock structures during coal seam excavation. By improving the ten-step phase-shifting algorithm, the study overcame the error issues associated with traditional digital photoelastic phase-unwrapping methods. This enabled the quantitative analysis of the evolution characteristics of principal stress difference and shear stress within the surrounding rock structures caused by the advance of the working face. The study further revealed the evolution of the "unloading arch", the migration of low-stress zones during mining, and the stress response characteristics in the vicinity of fault. It also identified sensitive regions prone to fault instability and slip under mining influence and proposed the critical conditions for fault slip.The results show that when the fault reaches a critical slip state, the unloading arch merges with the low-stress zone, causing the unloading zone to expand vertically to approximately six times the coal seam height. Meanwhile, the principal stress difference at both ends of the unmined coal seam increases to more than twice the baseline level, and the shear stress on the fault surface rises to approximately 1.3 times its initial value. This research provides both experimental support and a theoretical foundation for accurately understanding the mechanisms and influencing factors of mining-induced fault-type rock burst, thereby contributing to precise risk assessment and effective hazard control.