Abstract: Based on the characteristics of low frequency periodic pulse pressure, a new method was proposed for seepage control and reinforcement of a dam. A prototype test of a manmade homogeneous embankment demonstrated that the method, considering drilling disturbances and repetitive pulsating pressure on the permeability of strata, was feasible. The clay-cement slurry pulsation diffusion equation was determined using the multi-coupling software COMSOL to investigate the mechanism of fluctuating pressure under the clay-cement slurry diffusion. Finally, this research was successfully applied to the Hebi section of the middle route water diversion channel along the grout curtain slope. The results showed that the 28-day strength of stone was greater than 2 MPa and the permeability coefficient was reduced to approximately 10?5 cm/s, demonstrating that the clay-cement slurry pulsation control grouting technology can significantly improve the stratigraphic continuity. Observations were made on the slurry in the grouting hole near the soil and cement block, the adjacent grouting hole slurry vein staggered lap joint, and the overall performance of the impervious wall space of the three-dimensional structure. Based on a comprehensive analysis of the numerical simulation and the field test results, the dam grouting time fluctuation should remain between 1 800 s and 2 400 s, a reasonable grouting pressure pulsation should be between 0.2 MPa and 2 MPa, the pulse duration should be between 4 s and 8 s, and the pulse interval time should be adjusted to between 2 s and 6 s. These values ensure that the seepage and the reinforcement of the dam grouting remain in optimal engineering ranges. The channel slope continuity and integrity were improved, and significant improvement was noted for grout reinforcement sealing. The coefficient was reduced to 10?5 cm/s, and the core sample remained as a whole with the length up to 40 cm.

Key words: dam, pulsating grouting, clay solidified slurry, prototype test, numerical simulation, South to North Water Diversion Project