| 摘要 |
PROBLEM TO BE SOLVED: To provide an entrance packing device surely enabling a cutoff when a tunnel is built by using an excavator, in which a joint section is projected from an external surface, and a tunnel shell element. SOLUTION: The entrance packing device has an excavator body 14, a male joint section 22, a first packing 38 having a first hole 76 approximately corresponding to the outside diameter of a female joint section 24 and being installed on the wall surface 54 side of the starting shaft 30 and a second packing 40 having a thickness thinner than the packing 38, having a second hole 78 smaller than the hole 76 and being mounted on the inner side of the shaft 30 than the packing 38. A section inner than the hole 76 of the packing 40 is penetrated to the starting-shaft entrance 32 side, exceeding the hole 76 in the case of a pipe jacking by the excavator body 14, and a push-back to the starting shaft 30 side from a starting-shaft entrance 32 of the packing 40 by water pressure is prevented by the packing 38. COPYRIGHT: (C)2004,JPO
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