Abstract: In the light of the ultrasonic technology which has been applied effectively in the petroleum industry, an ultrasonic plugging removal system which is suitable for dike relief well has been independently developed. The process of backward silting of the relief well was simulated in a large laboratory permeameter, and the self-developed ultrasonic equipment was employed to remove the plug. The effect of the proposed ultrasonic technology was studied through permeation test with constant water head, and the influence of sand sample density and driving hydraulic gradient on the effect of ultrasonic technology were also studied. The experimental results revealed that the aquifer was blocked by the reversed filling suspension. The drainage capacity of relief well dropped, and the artesian head rose. After the plugging removal using the self-developed ultrasonic technology, the permeability of the relief well and surrounding aquifer was enhanced, the outlet flow of relief well pipe increased, and the decompression ability was ameliorated. The relief well recovered by over 60% using the present ultrasonic technology. In addition, reducing the density of sand sample raised the porosity of sand sample and boosted the drainage and decompression capacity before silting, but the silting degree could aggravate. The density of sand sample had no significant effect on the degree of ultrasonic plugging removal. However, with small sample density, ultrasonic technology can achieve equal plugging removal effect in a short time. Escalating the driving hydraulic gradient in the process of ultrasonic de-plugging could help upgrade the ultrasonic effect by prompting the exfoliated silt fine particles to precipitate out from the aquifer.

Key words: dike relief well, backward silting, ultrasonic, plug removal system, penetration test