| 摘要 |
PROBLEM TO BE SOLVED: To construct a branching/confluent part by a shield machine of ordinary specifications, without requiring to construct a shaft possessing an aboveground part. SOLUTION: A segment of the branching/confluent part of a preceding tunnel 100 is constructed by a steel material structure segment 101, and before penetratingly passing the shield machine of a confluent underground tunnel, a concrete partition wall 110 is arranged in the preceding tunnel, and a cylindrical segment removing device 10 is arranged, and while being pressurized and circulated by injecting and filling an electrolytic solution 24a from the aboveground part into a space for fluid-tightly sealing the inner periphery of the steel material structure segment and the outer periphery of the segment removing device, the steel material structure segment 101 is electrically eroded and removed by anodic melting by impressing voltage from a DC power source 17 with the steel material structure segment 101 as an anode and the segment removing device 10 as a cathode, and is substituted with a filler capable of excavating by the shield machine. COPYRIGHT: (C)2007,JPO&INPIT
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