关键词: CFG桩, 损伤模型, 倾斜基底, 数值分析, 破坏模式

Abstract: The instability failure mechanism of rigid pile composite foundation under horizontal layered embankment has been studied in depth. However, regarding to the instability failure mode and failure mechanism of rigid pile composite foundation under super- high fill embankment and under inclined foundation conditions, there is still a lack of in-depth disclosure. Based on a project, the ABAQUS finite element software is used to establish a three- dimensional numerical model of the CFG pile composite foundation under the super-high fill load. Taking the stiffness damage of the pile into consideration, the failure mechanism of the CFG pile is studied. The results show that the concrete damaged plasticity model can simulate the mechanical properties of CFG piles well, and can reasonably display the actual process of pile stress release and internal force redistribution after pile failure, and the progressive damage of the CFG pile composite foundation can be analyzed by the software's damage output variable. Under the
effect of ultra-high filling load, the CFG pile on the inclined base may be bent or fractured, and its load-bearing characteristics and failure mode are quite different from those of horizontal layered embankment, which is represented by the bending moment of the central pile of the embankment. The shearing force is relatively large, and the bending and shearing damage of the pile is more likely to occur which is worth attention during design. The bending moment and shearing force of the pile on the left side of the embankment are generally smaller than that of the central pile, and is of less possibility of first damage to it.

Key words: CFG piles, damage model, inclined substratum, numerical analysis, failure mode