Abstract: In this paper, based on the uniaxial compression test of intact rock samples, the confined grouting reinforcement of cracked rock samples were carried out, and the mechanical properties of grouting reinforced samples were also tested by using self-made grouting system. Meanwhile, the microstructures of cracked rock samples before and after grouting reinforcement were observed by KH-3000 Videomicroscopy. The results show that there are a lot of interpenetrated fissures in cracked samples, and the fracture mechanisms of samples are mainly the tensile failure. Compared with residual strength, the strength of grouting reinforced samples are increased at different degrees due to the filling and consolidation of fracture planes, but the strength recovery coefficient is not high. In addition, the confined grouting reinforcement can promote the transformation of cracked rock samples deformation from brittleness to ductility, and make the lateral and vertical deformation tend to coordination. Moreover, the confining pressure has great effect on grouting amount, radial stain, strength of grouting reinforced samples and strength recover coefficient, and the reinforcement effect can be improved significantly by increasing the confining pressure.

Key words: cracked rock mass, confined grouting, mechanical characteristics, uniaxial compression