Investigation of the instability of surrounding rock deformation in deep roadway: From the perspective of stress-driven crack evolution and plastic zone extension

Instability of surrounding rock in deep roadways is a key issue in the research on safe and sustainable mining in coal mines. The development of rock cracks and the expansion of plastic zones directly affect roadway stability, and are likely to lead to disasters such as large deformations, roof caving, and sidewall spalling. This paper focuses on the mechanical mechanism of crack development in the surrounding rock of deep roadways. By establishing a mechanical analysis model, conducting discrete element numerical simulations, and analyzing the engineering case studies, the study extensively investigates the progression of crack development and the propagation of the plastic zone in the surrounding rock of roadways. The study clarifies the stress evolution characteristics of the surrounding rock, revealing the mechanical mechanism by which stress drives crack development, leading to the macroscopic instability of the surrounding rock. Additionally, it identifies the relationship between crack development and the distribution of plastic zones in the surrounding rock. The study emphasizes that the damage to the surrounding rock in the disturbed area near the deep roadway aligns with the direction of the minimum principal stress ( σ 3 ). Moreover, the extension direction of the plastic zone closely corresponds to the direction of propagation of tensile cracks. A risk zoning method for rock layer instability was proposed based on the characteristics of crack development and plastic zone distribution in the surrounding rock. The reliability of the research results was validated through engineering case studies. The research findings have significant theoretical and engineering implications, offering insights into the process of surrounding rock instability in deep roadways and providing a basis for formulating effective control strategies. • A mechanical analysis model was constructed for the formation of macroscopic cracks by activation of fissures by main stress deflection in the surrounding rock of a deep roadway, revealing the mechanical mechanism of the formation of cracks in the surrounding rock. • The elucidation of cracks development in the adjacent rock and the expansion of the plastic zone during roadway construction has been clarified, unveiling the correlation between the crack distribution in the surrounding rock and the distribution of the plastic zone. • Drawing upon the crack formation characteristics and the plastic zone distribution in the roadway perimeter rock, the risk area for instability in the perimeter rock was categorized, and relevant support recommendations were provided.