| 摘要 |
PURPOSE:To promote execution efficiency and to reduce a cost by forming circular segments having the same form, and assembling it in a cylindrical shape by using a box shield excavator having a polygonal section. CONSTITUTION:A box shield excavator 20 with a square section, etc., having a drum cutter 1 and rig cutters 2 is provided. After that, an erector ring 7 is placed in the excavator 20 in a freely turnable manner and, at the sametime, inclined jacks 12 and 13 are provided thereto through a coupling member 18. Then, circular segments 15 and 16 having the same form are formed. After a segment 15 other than the top is held by a holding section 14 of the front end of the jacks 12 and 13, the ring 7 is tunnel to set it in a specific position. In addition, the last segment 16 of the top is mounted, and after the member 18 and the jacks 12 and 13 are operated to project the sent to the outside once. it is moved downward to load it in a specific position. According to the constitution, execution can be safely and efficiently carried out, and a cost of the segment can be reduced. |
