Experimental study on the effect of grouting reinforcement on the shear strength of a fractured rock mass

To study the strengthening mechanism and effect underlying the reinforcement of a fractured rock mass with grouting, compressive shear tests were conducted with an RMT-150B rock mechanics test system. Prefabricated structural surfaces were strengthened with a new inorganic dual-liquid grouting material at five water–cement ratios (0.6–1.5). The effects of these water–cement ratios of the grouting on the deformation, strength, and failure characteristics of the prefabricated structural surface were analyzed. The results show that reinforcement with grouting significantly influenced the bearing capacity of the structural surface. The shear strength of the structure was significantly improved and the deformation resistance of the structural surface was enhanced. The shear stress–displacement curves, generated in compressive shear tests of the grouting-reinforced structures, were all nonlinear. The shearing process comprised three stages: elasticity, yield, and failure. Decreasing the water–cement ratio of the grouting material weakened the plasticity of the grouted structural surface and enhanced its brittleness. The deformation type changed from plastic slip to brittle shear. The shear strength, cohesion, and angle of internal friction of the grouting-reinforced structural surface increased with decreasing water–cement ratio.