| 摘要 |
PROBLEM TO BE SOLVED: To provide a circulating water seal boring system preventing a hole wall from being plugged. SOLUTION: The circulating water seal boring system 10 circulating sealing water in a bore hole 2 by supplying/draining water into/from the bore hole 2 includes a packer 12 blocking a hole opening 2a; an outer pipe 14 provided penetrating the packer 12; and an inner pipe 16 arranged inserted close to a hole bottom 2b through the inside of the outer pipe 14 to secure a clearance 22 between its outer peripheral surface 16a and a hole wall surface 2c and protrusively provided with spacers 20 for controlling the flow direction of the sealing water. COPYRIGHT: (C)2011,JPO&INPIT
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