Comparison of penetration resistance and vertical capacity of short piles installed by Standard Press-in in loose sand

In the Press-in Method, a vertical jacking force required for installing a pile is automatically measured for every single pile. This information is expected to be utilized to confirm the vertical performance of the pile. In this paper, results of a series of large-scale model tests are reported to compare the resistance during installation and during static load test. The test pile was a closed or open-ended tubular pile with an outer diameter of 318.5 mm, embedded in a loose sand to around 6 m. Phenomena of pile set-up or set-down were observed in some cases. Through literature review and detailed analyses of the experimental data, the cause of the set-down was concluded to be mainly due to the pile installation being terminated at a depth where the soil strength decreased with depth and to a lesser extent because negative pore water pressure was generated during installation.