Light, efficient piling rig including drilling tool with cased section carrying shallow spirals

摘要

This new unit forms in-situ concrete piles. Following boring by displacement drilling, the foot of the pile is to be integrated into solid, load-bearing ground. The new drilling tool includes a displacement drilling tube (1). Its outer diameter is just less than the diameter of the bore being constructed. This tube carries a continuous spiral (2), projecting only a few centimetres beyond its surface. The tube length covers the displacement bore (9). At the base of the tube the spiral drilling screw (3) is fastened, its length (6) corresponding to the depth to be drilled in the load-bearing ground and its outer diameter the same as that of the upper spiral section. The shaft (13) is as small in diameter as feasible, and is controlled by that of the concreting tube (4), whilst also offering the minimum drilling resistance. Also claimed is the correspond method of piling.