Image Number 10 for United States Patent #4842447.
The invention is related to a kind of fabrication method and device of hollow reverse circulation piles of which the central hollow portion is installed with a movable sand barrel between which and the surrounding reinforcing cage, positioning device for movable sand barrel is installed. For starting the work, grouting to scheduled height from bottom of pile bore is made first and then grouting between pile bore wall and outer wall of movable sand barrel is conducted. Meanwhile, sands are poured into movable sandbarrel. By virtue of sensors on the inner and outer walls of movable sand barrel, the pressure between concrete grout and sand will be kept in equilibrium to avoid reverse grouting due to opposite pressure. Then, the sand barrel is pulled up step by step so that the pile poured with sand at its central part is primarily completed. Water is finally poured into the central part and sand is suctioned out to complete the hollow-typed reverse circulation pile. Its distinctive features are simplified and quick work process at low cost with high commercial value.