| 摘要 |
PROBLEM TO BE SOLVED: To provide an economical long-sized forepoling construction method for enabling reuse (repetitive use) of a guide pipe. SOLUTION: In this long-sized forepoling construction method, the guide pipe 11 is installed obliquely and upward in the front of a tunnel in the direction of tunnel excavation from a cutting face 71 in the vicinity of a boundary of the cutting face 71 in a tunnel cavity part 70 and an internal wall face 72 of the tunnel cavity part 70, and then a long pipe 12 having a smaller diameter than that of the guide pipe is installed on the natural ground 50 through the guide pipe 11 to reinforce the natural ground 50. A guide pipe constituted by connecting a plurality of separable unit pipes 11A mutually in the longitudinal direction is used as the guide pipe 11 in this construction method. COPYRIGHT: (C)2010,JPO&INPIT
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