| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for opening a hole on a sheath tube for re-injecting precast concrete grout, the hole being opened on a precast concrete structure at a diameter small as possible and damaging the precast concrete structure only a little, without a concern over a damage to a tensile material inserted into the sheath tube, and the hole being opened in a short period of time.SOLUTION: A method for opening a hole on a sheath tube for re-injecting precast concrete grout is for opening a hole on a sheath tube Y of an existing precast concrete structure X for re-injecting precast concrete grout into the sheath tube Y, and includes the following steps: a concrete drilling step in which a concrete part of the precast concrete structure X is drilled to a position close to an outer surface of the sheath tube Y, using a drilling machine 2 having a drive motor 20 for rotating a shaft 21 and a drill bit 22 measuring 30 mm or less in diameter and fitted at a tip of the shaft 21; and a sheath tube hole opening step in which a hole is opened from an end of a hole H1 drilled in the concrete drilling step to penetrate through a part of the sheath tube Y, by striking a sheath surface using hole opening jigs 5 to 7 made of a material of a hardness lower than a tensile material inserted into the sheath tube Y.SELECTED DRAWING: Figure 13 |
