Experimental and Numerical Study on Shear Behaviors of Rock Joints Reinforced by SFCBs and BFRP Bars

To study the shear behaviors of jointed rocks reinforced by basalt fiber-reinforced polymer (BFRP) bars and steel–FRP composite bars (SFCBs), we conduct laboratory tests and numerical simulations to analyze the shear strength, shear stiffness, energy dissipation, and bolt failure modes. Our results show that the shear stiffness of the BFRP bolted specimen is lower than that of the specimens bolted by steel bars and SFCBs, but the residual shear strength is higher. SFCB-reinforced jointed rock has the highest peak shear strength, and its residual strength is similar to that of the steel bar bolted specimen. The total energy absorbed by the BFRP bolted specimen is comparable to that absorbed by the steel bolted specimen. When the bolt inclination angle is 60°, the shear strength of the BFRP bar bolted specimens is higher than that of the steel reinforced one. The failure characteristics of BFRP bar bolted rocks can be categorized as resin matrix fracture, resin matrix and fiber shear, and fracture of resin matrix and rocks. The failure modes of the SFCB divided into surface FRP failure and steel bending. Based on numerical results, BFRP bars have larger axial force than conventional bolts, but lower shear stress. The axial stress of the BFRP bar increases as the bolt inclination angle decreases. Moreover, the BFRP bar is more likely to cause shear cracks at the interface between the rock and the bolt.