Abstract: The aim of this research is to investgate the influence of pumping and drainage time on the bearing characteristics of static drill rooted drainage pile. Several groups of model tests of static drill rooted drainage pile and ordinary static drill rooted pile were performed with pumping and drainage time as the variable to compare the change of pore pressure and the bearing capacity of pile foundation at different stages. Results show that in the process of vacuum-pumping, the pore pressure around drainage pile dissipates rapidly within the first eight hours, and then slows down gradually. Compared with that of ordinary static drill rooted pile, the ultimate bearing capacity of drainage pile foundation after vacuum negative pressure pumping and drainage for 3 hours, 8 hours, and 72 hours, increases by 56%, 61%, and 74%, respectively, and the anti-deformation ability increases by 10.2%, 89.8% and 124.5%, respectively. Pumping and drainage has a good popularizing value as it significantly accelerates the cement-soil solidification, improves the mechanical properties of soil around the pile, and then enhances the bearing capacity and anti-deformation capacity of the pile foundation.

Key words: static drill rooted drainage pile, model test, drainage time, cement soil, bearing capacity