| 摘要 |
Multistage manufacture of a borehole between two earth shafts 1, 2, a drilling machine 3 first creates and cases a pilot bore between a starting shaft 1 and an end shaft 2, and then an expansion bore is made and cased-in by pulling the expansion tool 7 in the opposite direction, and the accumulating earth is transported solely into the end shaft in opposition to the drilling direction possibly with the aid of a screw conveyor 11, 12. |
