Abstract: With the development of the technique for constructing the cast-in-place piles with high frequency vibratory hammers, the cast-in-place piles have been widely used in construction engineering. The penetration mechanism of the pile sleeve driven by high frequency vibratory hammers remains unclear, and particularly the squeezing effect in the sleeve penetration has yet to be investigated. In this paper, a finite elements and infinite elements coupling model is developed for simulating the sleeve penetration process driven by high frequency vibratory hammers, and used to study the squeezing effects such as ground heaves, lateral soil displacement and excess pore pressure generation. The results indicate that the horizontal displacement induced by soil compaction increases with the increase of sleeve penetration depth, and for the vertical compaction displacement, the heave increases in shallow soil layers and the settlement increases in deep soil layers as the sleeve penetration depth increases. The maximum compaction displacement lags behind the sleeve penetration depth. The reason for heave in shallow soil layers is that the horizontal stress increment causes an increase in the vertical stress, and the depth of heave interface increases with the increase of dynamical load amplitude, while decreases with the increase of vibration frequency. The excess pore pressure increases with the increase of sleeve penetration depth, and exhibits an exponential attenuation trend as the radial distances increases.

Key words: sleeve for cast-in-place pile, high frequency vibration, squeezing effect, finite elements