| 摘要 |
PROBLEM TO BE SOLVED: To form a branch junction part of a tunnel by directly cutting a joint side face part of a main line tunnel with a branch junction tunnel shield boring machine while stably supporting earth pressure and water pressure from the surrounding ground. SOLUTION: This branch junction part construction method for a shield tunnel includes the processes for installing horizontal temporary support beams 21 between an internal wall surface 19 of the main line tunnel 11 and an internal wall surface 20 of a branch junction tunnel 12, arranging connection pieces 24 each having an abutting surface 24a on an end face of a tunnel outer enclosure body 15 of the main line tunnel 11, an abutting surface 24b on an end face 16a of a tunnel outer enclosure body 16 of the branch junction tunnel 12, and an abutting surface 24c on one end face 25a of a horizontal proper support beam 25, while covering the natural ground surface 26 of a joint side face part 12a exposed by removing cut segments 14, and removing a main line temporary center pillar 18 and a branch junction line temporary center pillar 21 after erecting each horizontal proper support beam 25 between the abutting surface 24c of the connection piece 24 and the internal wall surface 19 of the main line shield tunnel 11 in place of the horizontal temporary support beam 21. COPYRIGHT: (C)2007,JPO&INPIT
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