Effect Of Pile Spaceing On The Performance Of PCC Pile Composite Foundation

It has been acknowledged that PCC pile composite foundation is very effective in improving soft ground where a strict settlement control is mandatory. However, as a new technique treating soft ground, the theoretical research of PCC pile composite foundation is falling far behind its practices. Particularly, the effect of pile spacing on the behavior of PCC pile composite foundation is not well documented and thus delays its applications in field works.A study is launched to address the effect of pile spacing on behavior of PCC pile composite foundation, especially the settlement of composite foundation. The objectives include verification and mechanism study of controlled settlement by adjusting pile spacing, which may provide valuable supports for future experiences. A combination of field study and FEM analysis is used to research the effect of pile spacing on composite foundation. Followings are the main works fulfilled.1. The mechanism of PCC pile composite foundation, the effects of pile spacing on the settlement rate of composite foundation, the load bearing ratios of pile and soil, and the effective improving depth of composite foundation are analyzed through a field study which monitors the behavior of composite foundation with changeable pile spacing.2. The critical issue of interface between pile and soil is addressed by using a FEM for composite foundation. The failure mechanism of interface is analyzed and suggested from an energy viewpoint, which may help the establishment of interface constitutive model and the selection of interface element types.3. The behavior of composite foundation is analyzed by using a 3-D pile-soil interaction FEM. The effect of pile spacing on composite foundation is thus obtained in theory, which is in agreement with field monitoring data.