Revealing the impacts of fracture morphology and grouting parameter on the slurry diffusion behavior in rough rock fracture with flowing water: Insights from numerical modeling

Investigating the slurry diffusion behaviors in rough fracture with flowing water is essential for predicting the sealing efficiency and optimizing the grouting design. To study the slurry diffusion behaviors in rough fracture with flowing water, a slurry-water two-phase flow model in rough rock fractures with flowing water was proposed utilizing the CLSVOF method, the rhombus-square algorithm, and the Bingham rheological model. The numerical model was validated against theoretical solutions and experimental results. Subsequently, the influences of fracture roughness, fracture aperture, grouting hole diameter, water flow rate, and grouting pressure on slurry diffusion behavior were systematically studied. The results reveal that slurry diffusion undergoes distinct morphological transitions: initial circular diffusion, followed by an asymmetric elliptical shape, and ultimately U-shaped distribution. Water scouring is mainly observed at the upper region, sides, and outlet of the fracture. Fluid pressure decreases with increasing distance from grouting hole and increases over time during grouting. Greater fracture roughness reduces the scouring effect of flowing water and increases fluid pressure. Larger fracture apertures reduce sealing efficiency and promote slurry deposition. Increasing the grouting hole diameter significantly improve the slurry diffusion speed and sealing efficiency. In contrast, higher water flow rates accelerate slurry diffusion speed but intensify scouring along the fracture sides, thereby reducing sealing efficiency. Once the grouting pressure exceeds a certain threshold, its effect on final sealing efficiency becomes marginal. Higher water flow rate and grouting pressure leads to increased fluid pressure near the grouting hole. These findings provide valuable insights for predicting slurry diffusion behavior and optimizing dynamic water grouting strategies in fractured rock masses.