Based on the principle of fluid-structure coupling numerical simulation program, PFC2D particles flow, which uses its built-in FISHTANK function library and FISH language, the flow equation and pressure equation of fluid domain have been defined. The process of grouting slurry diffusion in the formation and shape are simulated and calculated. By adjusting the parameter of step and perm in PFC’s command stream, grouting effects in different penetration gravels are obtained. Numerical simulation indicates that action modes between serous fluid and ground soil are mutually affected by the grouting pressure; foundation structure will be destroyed as the grouting pressure increases excessively. Stressed states around the drilling hole have been analyzed theoretically. The theoretical results are consistent with the simulation ones. When split grouting action occurs the porosity and strain increase.