Abstract: Scaling off disease commonly develops in the rammed-earth Great Wall in Northwest China. In order to delay the deterioration process of the Great Wall, more effective reinforcement methods were explored through experiments. First, based on the measured thickness of peeling layers, a liquid-supply duration test was conducted to determine the optimal slurry supply time, which was identified as 18 h for achieving the intended penetration depth. Subsequently, liquid-supply optimization tests were performed, and the most favorable supply mode was selected according to the position of the slurry, the infiltration amount of the slurry, and the water distribution in the wall. To evaluate the reinforcement effect when the penetration purpose was achieved, samples from different radii of the wall in the reinforcement area were tested through wave-velocity test, hardness test, wind erosion test, and disintegration test. In addition, scanning electron microscopy was employed to compare the microstructures of untreated and electro-osmotic-reinforced specimens, aiming to elucidate the underlying strengthening mechanism. The results show that intermittent liquid supply can improve the uniformity of slurry distribution and reduce the difference of water distribution along the radial direction. What’s more, the reinforcement effect of slurry on-off ratio of t∶1 is better than t∶2. Microstructural analysis further reveals that the pores of the reinforced soil are obviously reduced significantly.

Key words: scaling off, electro-osmotic grouting, intermittent liquid supply, infiltration, reinforcement