| 摘要 |
PURPOSE:To construct a continuous wall which is excellent in impermeability, by a method wherein muddy water and impermeable material can be injected through a hollow fixed frame from the forward end of each bit and the lower end of a hollow fixed frame, and an anvil and a driving mechanism are provided. CONSTITUTION:The upper end face of a rod 2 is struck by means of an anvil 16 through driving of a striking device 15 as a rod 2, projected from the lower end of a hollow fixed frame 1, is rotated, and this performs excavation of a ground 22. Thereafter, simultaneously with excavation of a hole, muddy water 26 is forcibly fed to a muddy water injection pipe 5 to inject it through the forward end of each bit to excavate the ground down to a given depth. An impermeable material, such as mortar, concrete, is forcibly fed to an impermeable material injection pipe 6, and is injected in a hole to replace the muddy water 26 with the impermeable material. This enables excavation of a high- precise continuous hole, enables prevention of collapse of a hole wall through injection of the muddy water 26 into the hole during excavation, and permits an increasse in an impermeable effect without being influenced by crack and a crushed band in a bedrock. |
