Study on visual simulation experiment of water-displacing grouting in fractured aquifer

In this study, a visual test platform for water-displacing grouting in a fractured aquifer is innovated which involves transparent materials and a coloring fluid design, thus making the visual monitoring of the water displacement by slurry possible. Meanwhile, various parameters, including the grouting pressure, fracture water pressure, fracture opening, fracture angle, and fracture combination form can be adjusted based on demand to further study the mechanism of water-displacing diffusion by slurry in the fractured aquifer under the comprehensive action of multiple factors. The reliable experiment platform is verified by comparing the theoretical and experimental results of grouting in a single fracture. On this basis, the experimental study on the water-displacing diffusion by slurry in the fracture networks is carried out. The conclusions are as follows: (1) in the bifurcated fracture structure, the pressure at the intersection of the main and minor fractures is most affected by the width of the minor fracture, and the pressure change at different positions equidistant from the intersection of each minor fracture increases with growing included angle between the main and minor fractures; (2) the pressure at each point in the fracture network escalates linearly with the growth of grouting pressure, and the closer to the grouting opening, the greater the pressure growth value; and (3) the water–cement ratio has no significant effect on the pressure of each point in the bifurcated fracture structure, but when the ratio builds up, the total time of water-displacing diffusion by slurry decreases.