Experimental and numerical analysis of jacked piles during installation in sand

The experimental and numerical analysis of piles jacked into sands are conducted to study the behaviors of sand surrounding the piles on meso-mechanical characteristics and macro-mechanical response. Comparing and analyzing different displacement modes of soil located at different positions relative to the piles demonstrate the process of soil deformation in the lab tests. It is shown by the displacement and the variation of void ratios of soil that the mode of soil displacement and compaction area around the end of the pile appears as a spherical expansion. The variations of dynamic base resistance and shaft resistance and critical depth are analyzed. On the basis of the lab model tests, PFC2D method is introduced to simulate the installation process of jacked pile. It is found that the results of numerical simulation are well consistent with those of the model tests. The macro-mechanical response is exposed by analyzing the variation of meso-parameters. The study is expected to contribute to disclose the mechanisms of compaction effects and the development of driven resistance.