Title:
METHOD FOR KEEPING HOLE, PARTIAL CASING FOR KEEPING HOLE, AND HOLE KEEPING DEVICE
Document Type and Number:
Japanese Patent JP3241023
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a hole keeping method which can easily eliminate the fear of collapse at a weak part without reducing the diameter of a dug hole, and to provide a hole-keeping partial casing for use in the hole keeping method, and a hole keeping device for inserting and fixing the partial casing into the bole.
SOLUTION: This hole keeping method forms an enlarged hole part 7 by partially enlarging a weak part 2 of collapsible nature in a hole 1 dug, then inserts a cylindrical hole-keeping partial casing 8 whose diameter can be increased into the hole while its diameter is reduced, and increases the diameter of the partial casing 8 in the enlarged hole part 7 to fix the partial casing 8 to the hole wall of the enlarged hole part 7. The hole-keeping partial casing 8 for use in the method comprises a plurality of casing pads each being long-sized and having an arcuate cross section and vertically arranged into a cylindrical shape, a plurality of collapsible link mechanisms which interconnect the adjacent casing pads in such a manner that the interval between the adjacent casing pads can be increased or reduced, and a locking mechanism for fixing the movements of the link mechanisms while the adjacent casing pads are held apart.
Inventors:
Naotaka Shigeta
Hideo Higashiomori
Hideo Higashiomori
Application Number:
JP17244199A
Publication Date:
December 25, 2001
Filing Date:
June 18, 1999
Export Citation:
Assignee:
Nuclear Fuel Cycle Development Organization
NLC Inc.
NLC Inc.
International Classes:
E21B10/32; E21B7/20; G21F9/34; (IPC1-7): E21B10/32; E21B7/20; G21F9/34
Domestic Patent References:
| JP61158592A | ||||
| JP893374A | ||||
| JP8254093A | ||||
| JP643090U |
Attorney, Agent or Firm:
Yukio Omata