Abstract: The implanted drainage pile can eliminate the excess static pore pressure in the adjacent soil layer and improve the soil strength on the side of the pile. It is a new type of pile foundation technology suitable for deep soft soil ground in coastal area. In order to study the dissipation law of excess pore water pressure and the development of consolidation degree in the adjacent soil layer, the cement-soil is regarded as the smearing zone, and based on the assumption of elliptic column drainage body and the coordinate transformation method, an analytical solution of consolidation of implantable drainage pile under vacuum negative pressure was derived. The reliability of the theoretical solution was verified by model tests, and then an example analysis was carried out. It is found that the vacuum negative pressure transfer is mainly concentrated near the vertical drain, and the plane distribution of excess pore pressure in the soil layer shows a shape of “8”. The duration of vacuum negative pressure and permeability of cement-soil have significant influence on the reinforcement effect of drainage pile. The permeability of cement-soil decreases rapidly under the action of drainage consolidation and hardening, and thus the duration of vacuum drainage should be controlled within 5 days. The research results lay the foundation for the further development and application of the implanted drainage pile technology.

Key words: drainage pile, static drilling rooted pile, vertical drain, consolidation, excess pore water pressure