Abstract: To investigate the longitudinal initiation and diffusion mechanism of rock fracturing and grouting, the movement law of the rheological property of slurry and the form of the crack propagation are analyzed considering the mechanical properties of the injected rock mass and ground stress. In addition, the longitudinal fracturing diffusion model considering the rheological property of slurry is established, and the initial pressure of longitudinal fracturing and the expansion conditions of fracturing channel are given. Taking the fracture geometry and the rheological property of the slurry into account, the slurry diffusion equation is derived and verified by experiments. Studies have shown that, in addition to the factors such as grouting pressure and grouting rate, the diffusion range is also controlled by the height of the grouting section, the strength of the injected rock body, and the rheological property of the slurry during longitudinal fracture grouting. These influencing factors are all negatively correlated with the fracturing diffusion radius and positively correlated with the grouting pressure. The rock mass with high strength and the liquid with great viscosity can lead to high resistance encountered by the fracturing grouting, which can further result in difficult crack propagation. The research results can provide a theoretical reference for fracture grouting designs of the bedrock in the future.

Key words: rock grouting, grout viscosity, longitudinal fracturing, diffusion mechanism