| 摘要 |
PROBLEM TO BE SOLVED: To provide a construction method for a tunnel branch part for reducing adverse influence effected to a surrounding environment by extremely reducing a required work yard on the aboveground side. SOLUTION: This construction method is characterized by constructing a branch part 5 by adjacently arranging a plurality of box body elements 10 in the peripheral direction by a pipe jacking method; forming an outer shell part 14 with a road 12 side aboveground part formed in a blocked-up cross-sectional shape as the starting end A, and with a side surface of a main line tunnel 1 as the terminating end B; and excavating the inside of the outer shell part 14 to be communicated with the inside of the main line tunnel 1. The initially arranging first box body element 10a is applied with thrust by a jacking machine 22 from the rear end side by excavating the ground from a starting end A point by a boring machine 20. In this case, reaction of the jacking machine 22 is taken via a bearing plate 26 by a ground anchor 24 arranged on the starting end A side. Next, the second box body element is adjacently arranged to the element 10a. When arranging the second box body element, the previously arranged first box body element 10b is used for receiving the reaction of the jacking machine 22. COPYRIGHT: (C)2005,JPO&NCIPI
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