Bolted bearing capacity and mechanism analysis of regenerated rock mass based on 3D printing

The interaction between regenerated rock mass and its support structure is complex. To clarify how bolted structures support regenerated rock mass,we investigated the effect of various support parameters on its bearing capacity. Using sand 3D printing technology,we designed and fabricated bolted specimens with different bolt densities and arrangements. We analyzed the reinforcing effects and relationships between support parameters,and examined the bearing mechanism of bolted structures through theoretical analysis. Results show that increasing the number of bolts initially improves the physical and mechanical properties of the regenerated rock mass,but excessive bolting can reduce these benefits. Lateral increases in bolt numbers gradually weaken reinforcement. Higher bolt density helps limit crack development and elastic strain energy release during loading, leading to reduced acoustic emission and lower strain concentration, which suppresses crack initiation and growth. We established a safety factor criterion for the stability of roof and rib bolting structures,confirming that bolt density significantly affects the properties of the bolted body. By coordinating support parameters with those of the regenerated rock mass and leveraging their characteristics,more stable control and optimized bolting design can be achieved.