Laying manner and that device null of the large-diameter pipe due to open

摘要

PROBLEM TO BE SOLVED: To efficiently and safely install a large diameter pipe underground by an open shield method. ;SOLUTION: The backfill end part is sufficiently compacted to shorten the backfill length by back-filling an anchor seat attachable/detachable to/from a lagging 3 supported in the vicinity of a mouth of a pipe P1, and burying it in the ground. The lagging 3 has through holes for hooks and anchor belts in a lower end to book the anchor belt of the anchor seat. Projecting frames provided on a transverse strap member and a longitudinal strap member of a tensioning and supporting device movable in the pipe are locked to a joining part pipe of an installed pipe, the device is connected and fixed to a receiving frame 7 of the lagging by a high tensile steel bar to prevent the pipe from coming off. The true circularity of the pipe is maintained by closely attaching the transverse strap member and the longitudinal strap member of a true circularity maintaining device movable in the pipe. Both devices have a hydraulic jack to closely attach both strap members to an inner wall of the pipe when the jack is expanded.;COPYRIGHT: (C)2001,JPO