Static drilling and rooted pile is a green and environmentally friendly pile foundation construction method, which is mainly composed of PHC pipe pile and cement soil around the pile, and the expansion head treatment is added near the pile end. In order to accelerate and enhance the solidification of cement soil at the head of static drilling pile and further enhance the bearing capacity of pile foundation, the technology of vertical drainage channel and vacuum negative pressure drainage at the expanding head of pile end is proposed. Model tests were carried out to compare the bearing capacity of static drilling pile and static drilling pile with extended head pumping and drainage. The test results show that: The vacuum negative pressure drainage can accelerate the hardening of soil-cement around the enlarged head pile and make it reach the final strength earlier than the traditional static drilling pile. Vacuum negative pressure drainage consolidation strengthens the soil around the pile and the soil at the end of the pile to a certain extent. The ultimate bearing capacity of the enlarged head drainage pile at 28 days of pile formation is about 59% higher than that of the ordinary pile.

In order to study the influence of groundwater flow on the bearing characteristics of static drilling deep-rooted energy pile in coastal area, a model test system of static drilling deep-rooted energy pile in 1.2 m thick soft clay interlaced with sand model ground was designed, so as to test and analyze the temperature, pore pressure, displacement and stress of pile-soil system with or without water flow. The results showed that groundwater flow reduced the temperature variation of pile, ranging from 6.39% to 34.15%. The temperature change of the downstream soil is obviously higher than that of the upstream soil, which is beneficial to reduce the thermal and cold accumulation effect of the soil around the pile. The water flow approximately reduces the hot pore pressure by 11% and the negative pressure by 20% in the surrounding soil, and the cumulative settlement of pile top is approximately reduced by 1/3. The tension stress of pile body caused by temperature is also reduced when groundwater flows. With the increase of load, the influence of water flow on friction decreases. Under the condition of underground flow, the maximum negative friction decreases under the rising and cooling conditions, which is conducive to the long-term work of static drilling of energy pile.