The 25mm thick weighty metal tube is driven Using the conclude closed by a steel shoe. On achieving the expected driving resistance, a complete length cage is reduced in on the tube and crammed with higher slump concrete. The tube is then vibrated out leaving a shaft of concrete. From https://cast-in-situ-piles-in-ban73880.post-blogs.com/53682149/new-step-by-step-map-for-cast-in-situ-piles