Performance Analysis of Rock Bolts at the Stope Back to Determine Suitable Reinforcement

In case of severe yielding around the excavations reinforcement is to be installed to improve the ground conditions. This study incorporate fully grouted rock bolts in the roof of stope backs for the analysis of performance of bolts in terms of axial load and shear stress that may develop along the interface of bolt rod and grout material. The performance of rock bolts is obtained as a function of bolt length, and bolt spacing for a given grout material property and a given geo-mining condition. The confinement provided to the rock mass is also estimated and analyzed for the improvement of safety factor of crown pillars. In this study, a steeply dipping orebody, having decreasing width with depth, has been modeled considering horizontal cut and fill method of stoping at four depth levels. These analyses have been conducted based on numerical models considering Drucker-Prager material model in plane strain condition. Results of the study provide valuable insight into performance of rock bolts, their impact on safety factors and confining stresses near the excavation boundary for proper design of reinforcement.