| 摘要 |
PROBLEM TO BE SOLVED: To provide a shield tunnel widening method which is inexpensively carried out without using a special shield machine etc. SOLUTION: According to the shield tunnel widening method, after construction of a shield tunnel by assembling segments, a chemical solution is poured into the shield tunnel to form a poured section 10a, and then an upper segment 5a is removed, followed by excavating the poured section 10a, to thereby form an excavated section 15a at a widening scheduled location. Thereafter a lower segment 7a is removed, and a lower portion widening segment 19 is set, followed by removing side segments 9a, 9b, 9c. Then the removed lower segment 7a and the side segments 9a, 9b, 9c are set at the widening scheduled location, and an upper widening segment 25 is set, followed by setting the upper segment 5a at the widening scheduled location. In this manner widening of the shield tunnel is carried out. In order to ensure the rigidity of the tunnel during execution of widening work, a jack timber 11, a lower support 21, and an upper support 27 are set in the tunnel. COPYRIGHT: (C)2009,JPO&INPIT
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