关键词: 软土地基, 单桩沉降, 桩身压缩量, 桩型

Abstract:

The deformation of single piles in soft foundation was studied based on more than 300 in situ data of pile including the settlements at pile-top and pile-tip. The piles are divided into four types: precast concrete pile, hollow concrete pile, steel pipe pile, and cast-in-place pile. Analyzing the in situ data with elasticity theory, a simplified method to predict the shaft compression of pile was presented based on the pile length-diameter ratio. It is shown that the shaft compression of precast concrete pile is the largest, while the compression of cast-in-place pile is the smallest. Therefore, the deformation of single piles is influenced by the squeezing effect obviously. The settlement at pile bottom was calculated by the layer-wise summation method, and the modified method to compute the settlement of single piles was obtained. The comparison analysis for 300 individual piles shows that the modified method can be used to calculate the settlement of pile at working load very well.

Key words: soft foundation, settlement of single piles, shaft compression of pile, type of pile