Study on diffusion law and mechanism of different types of single fracture grouting slurry

The small area pre-grouting of water-bearing layers is often used in shaft excavation, clarifying the slurry diffusion law is the basis for determining the slurry diffusion range and formulating the grouting schemes. Different types of grouting models for a single fracture considering the fluid-solid coupling effect were established. The influences of factors such as grouting pressure, grout density, and fracture opening on slurry diffusion and fracture deformation were analyzed. The grouting slurry diffusion tests for smooth single fractures and rough single fractures were conducted using the rock mass fracture grouting test system. The research results show that the farther the distance from the grouting hole, the smaller the slurry diffusion radius within the same period, that is, the slower the slurry diffusion speed. When the slurry spreads to a certain distance, the grout pressure at different grouting rates all drops to the same pressure. Increasing the number of grouting holes is more effective than increasing the grouting speed. The greater the roughness of the crack, the less the amount of slurry in the length direction of the crack, and thus the less the total amount of slurry required, that is, the shorter the grouting time.