Estimation on Pile Driving Resistance and Soil Plug Evolution Mechanism of the Small-bore Steel Jacked Pipe Pile in Silt Foundation

The estimation methods about pile driving resistance of the small-bore steel jacked pipe pile in silt foundation are not mature at present. The relation between pile driving and the soil property are studied using a qualitative approach according to the static sounding measurements and single pile bearing characteristics in the jack-up engineering of a historic building. And the soil deformation mechanism and soil plug formation and evolution rule are analyzed macroscopicly. The pile driving process includes two stages: the stage when the soil plug is unplugged, and the stage when the soil plug is plugged. The two-stage estimation formula of pile driving resistance is put forward and the fitting coefficients of pile tip resistance and side resistance are achieved. The estimation formula can reflect the pile driving resistance change in each soil layers.