Abstract:

The authors describe results from an experimental program in which instrumented model piles were jacked into layered soils in a test chamber. The pile sinking mechanism of jacked pile was discussed. A number of pile installations were carried out to study the change of penetration resistance，end resistance and side resistance with penetration depth of pile . The behaviors of different resistances crossing different soil interfaces during the process of pressing pile and soil pressure are obtained. Moreover, the test series was designed using both open and closed end to investigate the effect of different pile ending forms on the side resistance of pile, and the change of soil plug of open-ended pile during the penetration process are discussed. The experimental results indicate that the end resistance plays important role during penetration in clay soil; because of the pile side horizontal stress release, the side resistance decreases with the depth at the same elevation, appearing “friction fatigue”.

Key words: layered soil, jacked pile, penetration process, model test, end resistance, shaft resistance, piles