STUDY ON THE EXCESS PORE WATER PRESSURE RESULTED FROM PILE DRIVING IN SOFT FOUNDATION

A relatively high excess pore water pressure(EPWP) arises while driving a pile group in a workshop. The maximum reached 120 kPa. Furthermore, a Lateral displacement of about 1.5m of the piles top is observed after excavation of foundation to avoid the potential problems induced by instability of excavation of foundation and decrease of pile bearing capacities, two kinds of treatment processes as setting prefabricated drains before or after pile driving are adopted. By comparing the EPWP dissipation laws of the foundation which are treated by the two processes, it is found that driving pile should be carried out after setting vertical drains, and a suitable space between the vertical drains is helpful for dissipating EPWP. Moreover, such a treatment can ensure the safety of project, and is timesaving.