Instability Characteristics and Control of Steel Arch-Concrete Supported Deep Drifts under High In Situ Stress

As underground mining extends to greater depths, high in situ stress combined with fractured surrounding rock often leads to severe deformation and instability in drifts, which cannot be effectively controlled by conventional passive support concepts. Taking the -600 m crosscut drift of the Xindongzhuang Gold Mine as the engineering background, this study investigates the mechanical response of deep drifts and proposes a design-oriented framework for stability control. A three-dimensional numerical model in ABAQUS is used to evaluate the original steel arch-concrete support system, showing that it mainly responds after deformation occurs, resulting in stress concentration at the arch feet, significant roof displacement, and local structural failure. To overcome this limitation, an Active Self-Bearing Ring (ASBR) framework is established, in which prestress is introduced as a controlling factor and the interaction between support and surrounding rock is quantitatively described. Two parameters, the self-bearing efficiency coefficient and the stiffness matching coordination coefficient, are defined to characterize this coupled response. Comparative analyses using RS2 indicate that the proposed method not only reduces deformation but also modifies the mechanical response of the surrounding rock, leading to a more uniform stress distribution and a smaller plastic zone, with total displacement controlled within 2.1-4.2 mm. Field monitoring further confirms the effectiveness of the approach.