| 摘要 |
PURPOSE:To raise the efficiency of operations by a method in which an annular hole of the same diameter as a supporting pile is formed in the ground by a cylindrical drill, and soil discharged from the upper part of the drill in the annular hole is scooped and discharged by a bucket to the ground surface. CONSTITUTION:An annular hole is drilled in the ground by jetting pressure wate from a jet port 12 while turning the rotary support shaft 8 of a cylindrical drill 9, and the excavated soil is scooped up by a spiral projecting blade 15. A soil discharger 16 is lowered through a wire 22, buckets 19 and 19' are opened and lowered to the upper end position of the drill 9, and the buckets 19 and 19' are closed to house soil. The soil discharged 16 is then raised to discharge the soil to the ground surface. |
