Abstract: The static drill rooted nodular pile is a new type of composite pile foundation which consists of precast nodular pile and the cemented soil along the pile shaft. The bearing capacity of this composite pile is promoted via the cemented soil around the pile shaft which improves the skin friction and the enlarged cemented soil base which promotes the tip bearing capacity. A field test by self-balanced method is conducted to investigate the tip bearing capacity of this new type of pile; the theoretical tip displacement formula is also adopted to calculate the tip displacement of the composite pile. In addition, a model test is conducted to study the tip bearing capacity of the new type pile with different relative positions of the precast nodular pile base and enlarged cemented soil base. The results of the field test and model test show that: the enlarged cemented soil base can truly promote the tip bearing capacity of the new type pile; the tip bearing capacity of this new type of pile seems to be fully mobilized when the nodular pile tip is at the middle of the enlarged cemented soil base; the theoretical tip displacement formula can be applied to this new composite pile foundation; and the theoretical tip displacement-tip load curve fits well with the measured curve when the nodular pile tip is at the middle of the enlarged cemented soil base.

Key words: static drill rooted method, nodular pile, self-balanced method, enlarged cemented soil base, base bearing capacity