Numerical Analysis and Engineering Application of Polymer Grouting in Rough Fractures Under Slurry–Rock Coupling Conditions Based on Spatial Frequency Domain

The purpose of this paper is to analyze the diffusion mechanism of polymer slurry in rough fractures under slurry–rock coupling, which has important practical significance for polymer grouting repair of rock fractures. The rock mass fracture with random roughness is constructed in the spatial frequency domain, and the random rough fracture slurry diffusion model is established; then, a model experiment is established to verify the accuracy of the numerical method. Finally, the fluid–solid coupling diffusion mechanism in the grouting process is analyzed. The results show that (1) the maximum flow rate of slurry increases with the increase of overall roughness. The coarser the fracture, the more irregular the velocity distribution along the fracture opening direction. (2) The stress in rough fractures gradually decreases with the direction of slurry diffusion. The rougher the fracture, the greater the stress fluctuation, the more phenomena of stress concentration appear at the tip. (3) The stress field is greatly influenced by the shape of fractures, in depressed areas, where stress mutations can easily lead to plastic damage and secondary fractures.