Study on mechanical properties of coal rock grouting reinforcement under hydraulic fracturing

In order to solve the problems of instability and disturbance collapse of roadway surrounding rock in the process of coal mining, a splitting grouting reinforcement method is proposed. The splitting coal samples were grouted with cement-based slurry and epoxy resin with different water-cement ratios, and uniaxial compression experiments were carried out. Combined with acoustic emission and VIC3D monitoring system, the compressive strength and macroscopic failure characteristics of coal samples reinforced with different grouting materials were discussed. The experimental results show that: the compressive strength of grouting reinforcement increases with the decrease of water-cement ratio, and the strength of epoxy resin to the consolidation body is significantly improved, but the reinforcement effect is basically the same as that when the water-cement ratio is 0.6; in the aspect of the failure characteristics of the reinforced body, the stress concentration first occurs at the joints of the coal sample, with the extension of the loading time, the cracks are finally destroyed after initiation, expansion and penetration. The failure positions all occur in the non-reinforced zone, indicating that the splitting grouting reinforcement can improve the integrity of the coal rock.