| 摘要 |
PROBLEM TO BE SOLVED: To provide a backing prevention device capable of preventing backing in which a row of jacking pipes is pushed back to a starting shaft side when connecting the pipes during jacking in a jacking method. SOLUTION: The backing prevention device is constituted by: providing a cylindrical connection socket 8 which id internally threaded by a predetermined length in the radial direction from an internal surface of a wall to cross a wall surface orthogonally at a predetermined position of the jacking pipe 10; fittingly providing a fitting rod 4 of a backing support fitting into a special socket 7 from the outside of the jacking pipe 10 by a pouring hole formed by connecting the cylindrical special socket 7 and the connection socket 8 so as to make their axes coaxial from an external surface of the wall and the backing support fitting having the cylindrical fitting rod 4 having substantially the same length as the special socket 7 and inscribing the special socket 7 and provided with a bottom plate of a robust box body 3 connected with one end of the fitting rod 4; and abutting and fixing one face of side faces of the box body 3 on a movable fixing frame 11 provided at an outer peripheral part of the jacking pipe 10. COPYRIGHT: (C)2010,JPO&INPIT
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