Development of Grouting Test System for Rough Fissure Rock Body and Research on Slurry Diffusion Law

The surface roughness of grout in fractured rock masses has a significant impact on the diffusion characteristics of grout, especially in millimeter-scale fractures. In this study, a self-constructed experimental system for grouting in rough fractured rock masses was used to conduct grout diffusion tests with varying fracture roughness, fracture aperture, and grouting pressure. A theoretical model was developed to account for the combined effects of fracture roughness, aperture, and grouting pressure on grout diffusion, and its validity was verified. The results showed that the theoretical calculations and experimental results had an error rate of around 12%, indicating the high reliability of the theory. Fracture aperture, grouting pressure, and fracture roughness all exhibited nonlinear relationships with the grout pressure distribution. With increasing diffusion distance, the grout pressure decreased, and the rate of decrease gradually slowed down. Fracture roughness and aperture had a relatively small impact on grout pressure, while grouting pressure had a significant influence on grout pressure distribution. The difference in grout pressure between the initial and final stages of diffusion was small, whereas in the middle stage of diffusion, the difference was more pronounced. This research provides a valuable reference for the selection of grouting techniques in the roadway surrounding rock projects.