Micro-seismic (MS) technique can be used to appreciate rock failure process and severity of damage by quantifying micro-earthquakes in terms of time, location, grade, and energy release. Based on 3D laser detection and high-precision micro-seismic monitoring, this study analyzes the MS activity, stress and displacement evolution linked with the instability/failure property of hidden goaf incorporating several blasting disturbances in an open pit mine. MS monitoring outcomes reveal two arch fracture zones in the goaf roof, and MS occasions are mostly intense at rock-intersecting interface of north–south goafs. Evolution of apparent stress, apparent volume, and displacement reveals that the goaf is currently in a stable state. The current investigation offers a novel field method and view of inspecting the stability of goaf subjected to blasting disturbance in mines.

The creep behavior of deep weak rock masses is important due to an underground opening. Appreciating the nature and source of these deformations requires the knowledge of rock mass and ground support interaction. The theoretical solution of the backfill’s internal stresses needs to consider the time‐dependent effect. In the present study, the coupling interaction between the creep behavior of the nearby rock material and the internal stresses in the backfilled stope is considered and the interaction characteristics are given analytically. A solution is then proposed regarding the time‐dependent stress distribution in suborbicular backfilled stope interaction with creeping rock. Besides, the correctness of the theoretical solution is verified by numerical simulation, while influential parameters such as stope buried depth, lateral pressure coefficient, horizontal stress ratio, creep time of surrounding rock mass, delay time of the backfill, and Young’s modulus are thoroughly discussed. Research shows that when the stope buried depth becomes large as well as the rheological effect of the nearby rock materials becomes significant, the stress distribution in the backfill material exceeds its self‐weight stress and presents significant time‐dependent characteristics. The delayed backfilling weakens the backfill’s ground support effect on the nearby rock material. Hence, timely and multipoint simultaneous backfilling is needed for a stope with significant rheological deformation of surrounding rock mass. Lastly, this work will offer useful knowledge while designing the backfill materials for underground mines.

There are few studies on the management methods of large‐scale goaf groups per the specific surrounding rock mass conditions of each goaf. This paper evaluates comprehensively the stability of the multistage large‐scale goaf group in a Pb‐Zn mine in Inner Mongolia, China, via the modified Mathews stability diagram technique. The volume of each goaf to be backfilled was quantitatively analyzed in the combination of theoretical analysis and three‐dimensional laser scanning technology. The corresponding mechanical characteristics of the filling were determined by laboratory testing while formulating the treatment scheme of the large goaf group using the backfill method. The applicability of the treatment scheme using the backfill was verified by the combination of the numerical results of the distribution of the surrounding rock failure zone and the monitored data of the surface subsidence. The research results and treatment scheme using the backfill can provide a reference for similar conditions of mines worldwide.

This study investigates how mine backfill interacts with pillars to enhance load-bearing mechanisms in underground mining using the bonded-block modeling method. Through systematic numerical simulations of single- and three-pillar systems, we evaluate critical design parameters—backfill ratio, backfill’s cohesion, lateral confinement pressure, and pillar height-to-width ratio—to quantify their effects on cooperative load-bearing behavior. Key findings reveal that backfill provides essential horizontal passive support to pillars, with this stabilizing effect amplifying as the pillars fragment or undergo lateral expansion. Increasing the backfill-to-roof contact ratio due to the lateral expansion and squeezing effect of the pillar to the adjacent backfill strengthens the lateral constraints, reducing the tensile failures and axial crack propagation in the pillars at peak stress. In multi-pillar configurations, higher backfill cohesion improves system stability by redistributing loads across adjacent structures. Practical guidelines are proposed. Low-cohesion backfill with high filling ratios is recommended for single pillars to absorb energy during sudden failures, while high-cohesion backfill optimizes stability in multi-pillar systems. These insights advance the design of safer and more efficient backfill–pillar support systems in mining engineering.

This study investigates the stability of deep granite roadways under cyclic loading and unloading, focusing on the energy evolution of surrounding rock in the Sanshandao Gold Mine. In-situ stress measurements between − 835 m and − 1140 m reveal a horizontally dominated tectonic stress field, with both maximum and minimum horizontal stresses increasing approximately linearly with depth. On this basis, true triaxial cyclic loading–unloading tests were carried out on granite specimens to simulate burial depths of 500–2000 m. The results show that irreversible principal strains in the σ₁ and σ₃ directions increase approximately exponentially with cycle number, whereas the σ₂ direction exhibits an almost linear trend. With repeated cycling, axial elastic energy continues to accumulate while circumferential dissipated energy grows and then stabilises, indicating a damage-induced energy conversion mechanism in which a large part of the input energy is consumed by plastic deformation, frictional sliding and crack development rather than being released catastrophically. Using these insights, an energy-based support design framework was developed and applied to the − 1050 m haulage roadway at Sanshandao, where an optimised split-set support system with enhanced energy-absorption capacity significantly improved roadway stability. The proposed energy dissipation framework and associated support strategy provide a practical basis for mitigating dynamic hazards in deep hard-rock mining.

Using a tessellation method in Neper, the simplified 3DEC‐GBM (three‐dimensional discrete element grain–based model) is proposed for generating joint models with different roughnesses. The model is extended by implementing the generalized effective stress law to mimic the shear behavior of unsaturated sandstone. The grain‐scale mechanical parameters of the model were calibrated to correspond to the mechanical behavior of sandstone samples measured in the laboratories. The simulations accurately explain complex macroscopic shear behavior in terms of the mesoscale interaction of grains. The modeling results show that water has a deteriorating effect that weakens the strength of the joint, and the degree of reduction in joint strength rises with increasing saturation. Increasing normal stress and roughness can all improve the shear strength of the joint. We conclude that the proposed model is a convenient approach to analyze the shear response of unsaturated sandstone at varying roughness and normal stress.