Plugging Mechanism of Open-Ended Piles

The mechanism of the plugging phenomenon at the toe of vertically loaded openended piles was observed in this study by using a micro-focus x-ray CT scanner. The behavior of the surrounding ground at the pile toe is discussed based on the observation of the movement of iron particles, which were mixed into the sand and made layers in the sand layer. The movement of the sand particles was extracted from visualized x-ray CT data. In addition, the movement of the sand particles was extracted using the PIV (Particle Image Velocimetry) method. The CT images of the experimental results showed that the condition of the wedge formation below the open-ended pile was clearly different from that below the closed-ended pile. Although the penetration resistance of the open-ended pile and the closed-ended pile was similar, the movement of soil inside the open-ended pile was not stopped but restricted, as shown by intermittent increases and decreases in penetration resistance during pile penetration.