| 摘要 |
PROBLEM TO BE SOLVED: To provide a shield machine for a branch tunnel excavation capable of efficiently and accurately carrying out work thereof when a tunnel is bored by the shield machine toward the existing tunnel to construct the branch tunnel by making the tunnel communicate with the existing tunnel in a crossover state. SOLUTION: The shield machine A is so constituted that a plurality of divided hood members 2a are mutually and individually arranged on the circumferential surface of a skin plate in a forcedly drivable manner to form a cylindrical hood body 2 and, at the same time, that a screw auger 3 is integrally provided on each divided hood member 2a. The shield machine A is so constituted that each divided hood member 2a is driven forward while excavating the forward ground by the screw auger 3 when it reaches the existing tunnel T to abut the front end thereof on the circumferential wall surface of the existing tunnel, earth and sand taken in the hood body 2 are removed and, at the same time, that the circumferential wall section of the existing tunnel surrounded by the front end of the hood body 2 is disassembled to communicate a tunnel T' with the existing tunnel T in a branched state after a cutter head or the like is removed. COPYRIGHT: (C)2005,JPO&NCIPI |
