| 摘要 |
PURPOSE: A large diameter drilling method using a percussion rotary drilling (PRD) method is provided to drill most of an inner surface by using a PRD unit to successively drill the inner wall along the curved surface of the inner wall on an external casing, thereby easily and rapidly drilling big-sized holes. CONSTITUTION: A large diameter drilling method using a percussion rotary drilling (PRD) method comprises the following steps. A guide unit (10) is pressed in a position for drilling. Drilling units (20) for a PRD method are successively inserted into the space of the guide unit for drilling. An inner casing and a first connection unit are drawn. The remains of a drilled part are air-pumped out. A steel pipe is inserted into the drilled part. Grouting and cement are injected between an outer casing and the steel pipe. |
