| 摘要 |
PURPOSE: To construct a primary lining at the tip part circumferential part of a shield machine in parallel with boring operations without requiring any form. CONSTITUTION: An arch boring machine 3 with an outer boring cutter head 5, where a part of the circumference is situated more outward than a circumferential part of the skin plate 2, and an inner boring cutter head 4, where the circumference is situated to come nearer to an inner circumferential part of the skin plate 2, is set up in a tip of the skin plate 2 of an arch type sectional shield machine 1 free of movements in the arch direction of the skin plate 2. Natural ground is expanded more outward than the outer circumferential part of the skin plate 2 and it is bored into an tunnel arch type by both these cutter heads 4 and 5 rotating as shifting this arch boring machine 3 in the arch direction. The shield machine 1 is advanced forward as far as the boring width, and concrete 30 is poured into a cavity part 29 produced in the circumference of the skin plate 2 because of expansion boring and thereby a primary lining job is carried out, while the natural ground in an inner part of the shield machine 1 is thus bored. |
