Patent US 4,100,750

The invention relates to a hollow auger and to a method for producing piles cast in the ground. The method is characterized in that one uses an auger provided with a removable cutting head and which is able to slide in a sealed manner in the blade support tube of the auger and in that the injection of concrete, taking place through a central passageway provided in the cutting head, is undertaken in two successive stages, a first stage in which concrete is injected into the support tube by progressively raising the cutting head to a predetermined level, namely zero level in the latter and a second stage in which the auger is raised from the drill-hole by exerting a constant pressure on the cutting head and by injecting concrete in order to maintain this head at the predetermined level. The invention has application in the manufacture of piles cast from concrete.