Open-ended prestressed concrete pipe-piles jacked into soft clay interbeded with silt

The shortage of comprehensive research data to better understand the behavior of the jacked open-ended prestressed concrete pipe piles in soft clay interbeded with silt prompts an experiment program, in which a series of in-situ tests are conducted. Different developments of pore pressure are caused in the vicinity of the piles at different depths during pile installation. Two logarithmic correlations are confirmed to effectively express the function of the normalized peak excess pore pressure to the distance parameter. The maximum outward horizontal soil movement occurs in soft mucky clay layer with poor permeability. The vertical displacement around one pile decreases with the increasing distance, and a majority of the movement occurs during the shallow penetration. The pile annulus resistance and CPT cone tip resistance have similar development during penetration, and this relationship is independent on penetration depth and incremental filling ratio of soil plug. An open-ended pile is prone to performance in a plugged mode as penetrating into a weaker layer, whereas transition to an unplug-mode is observed on reaching an underlying harder layer. A larger diameter with a relative thinner wall for an open-ended pile leads to a higher plug length.