Study on the diffusion and migration law of anti-dispersion grout during the dynamic water grouting process in rough fractures

Anti-dispersive grouting materials are widely used in the sealing and management of sudden water disasters in mine fractures, and the study of its diffusion law and sealing effect in dynamic water fractures is of great significance for grouting operations and groundwater hydrology research. In this study, four groups of polyacrylamides (PAM) modified cement - sodium silicate (C-S) slurries with different viscosity characteristics were prepared and their rheological characteristics were analyzed. Spatial frequency synthesis was used to simulate the rough fracture surfaces, and the diffusion and transport processes of each group of slurries in different rough dynamic water fractures were numerically simulated. The results show that the high viscosity slurry has better grouting effect in the rough fracture of dynamic water. In the direction of parallel flow diffusion, the slurry with strong viscosity time-variable has the phenomenon of “viscous barrier”, and the loss of pressure gradient is slowed down with the distance of diffusion. The increase of the fracture roughness reduces the stability of the flow field in the process of grouting. However, in the direction of reverse flow and crosswise diffusion, due to the “retention effect” of slurry on the surface of rough fractures, the slurry shows a longer diffusion distance in the fractures with higher roughness.