Centrifuge Modeling of Stress and Pore Pressure Responses Due to Closed-Ended Pile Jacking in Silty Clay

摘要

A series of centrifuge model tests were performed to examine the short-term soil stress responses around closed-ended displacement piles during jacking in Shanghai silty clays. Miniature transducers were placed near the piles to monitor the evolution of the total radial soil stress and pore pressure at different positions, which were closely associated with the progress of pile penetration. The results show that these stresses accumulated when the pile approached and decreased when the tip (or shoulder) passed, which indicates that the transducers experienced a loading and unloading process. The maxima of the soil stress or pore pressure increased with the initial depth of the observation positions and decreased with the horizontal distance to the pile axis. Compared with the total radial stress, the arrival of the peak pore pressure had an obvious hysteresis. Three typical modes to describe the stress variations during the pile installation process were summarized. Furthermore, the cumulative total stresses and pore pressures at a given location because of the installation of two piles were investigated.