Field test and numerical simulation of precast pile with drainage channels on the side

In view of the challenges posed by construction on deep soft coastal ground, this study introduces the precast drainage pile (PDP) technology. This innovative approach combines precast pipe piles with prefabricated vertical drains, installed through static pile pressing and subsequently subjected to vacuum negative pressure for the consolidation of surrounding soil. To evaluate the efficacy of PDP technology, a comparative analysis was conducted between precast pile and PDP, incorporating field testing and numerical simulation. The investigation focused on the evolution of excess pore water pressure, deformation, and pile bearing capacity. Results indicated that vacuum negative pressure drainage could induce rapid initial dissipation of pore water pressure, followed by a slower rate. Excess pore pressure decreased more rapidly and significantly closer to the drained pile, aligning with drainage consolidation theory. After 5 days of consolidation, the PDP exhibited a 16% increase in ultimate bearing capacity compared with the undrained pile. Numerical simulation outcomes closely matched field measurements. The enhancement in pile bearing capacity was found to correlate hyperbolically with drainage time, culminating in a 26.5% ultimate increase. The research achievements facilitate the development of new pile technologies in coastal soft soil areas.