Abstract: Currently, industrial and mining enterprises primarily use grouting techniques to modify and reinforce water-bearing sand layers. Accurate grouting at the sand layer level and consolidation of loose water-bearing layers are key challenges in the grouting modification of deep wells with thick loose layers. This study proposes the concept of slurry-water replacement, derives the power-law fluid seepage diffusion equation considering the slurry-water replacement effect, and establishes and verifies the power-law fluid spherical permeation grouting diffusion mechanism under the slurry-water replacement effect through experiments. Using COMSOL, a three-dimensional numerical model of power-law fluid permeation grouting diffusion under the slurry-water replacement effect was established, and the seepage diffusion characteristics of power-law grout in water-bearing sand layers were analyzed. By analyzing the impact of porosity, grout hole spacing, and grouting pressure on the volume of water-bearing sand layers, the key factors affecting the volume of water-bearing sand layers were identified: grouting pressure > grout hole spacing > sand layer porosity. Slurry-water replacement grouting addresses the issues of limited grouting diffusion range and poor grouting effect in water-bearing sand layers under high water pressure.

Key words: water-bearing sand layer, power-law fluid, slurry-water replacement effect, penetration diffusion, numerical simulation