ABSTRACT
The theoretical formula of the cylindrical diffusion model of radial tube flow for sand layer penetration grouting, considering the tortuous effect, was embedded in COMSOL Multiphysics to explore the curtain formation mechanism of ground drilling grouting in a water-rich sand layer. The grouting of three adjacent grouting holes during a ground drilling grouting project for the main shaft of Guotun Coal Mine was numerically simulated. Moreover, the formation of a grouting curtain and the distribution law of the pressure isosurface and velocity field during slurry diffusion were analyzed. The results revealed that the volume fraction of cement slurry gradually decreased along the diffusion direction, and slurry volume fractions of (0.6, 0.8] corresponded to the key areas for grouting reinforcement. The isosurface of formation pressure changed from dense to sparse along the direction of slurry diffusion, indicating that slurry pressure rapidly and slowly attenuates near and far from the grouting pipe, respectively.
