The study of modeling experiment in loading properties for super-long single pile in over-wet loess

In order to explore the loading properties for super-long single pile in over-wet loess, a modeling experiment was designed in modeling basin in-door, in which displacement sensor was used to detect the displacement of pile top and camera and dial gauge were used to detect the displacement of pile bottom. The conclusion from the experiment was drawn as following. Axial force of piles decreased in a nonlinear way along the pile body, and the stronger loading was, the more obvious the nonlinear was. Axial force of hollow bottom pile decreased quicker than that of solid bottom pile. Lateral friction of foundation soil gradually acted with the loading increasing and the maximal lateral friction position likely moved down with the loading increasing. When reaching the maximal loading, the maximal lateral friction position was nearly at the 2/3 position of pile. That's the lateral friction of about 2/3 of pile reached the limit, and then the whole pile reached the limit. The relation curve between the lateral friction and displacement of the solid pile was mostly three lines type, while that of the hollow pile showed slow changing feature.