| 摘要 |
PROBLEM TO BE SOLVED: To improve draining efficiency in tunnel construction. SOLUTION: In a tunnel construction, an upper-half face 10 and a lower-half face 12 each have a draining bore hole 14 formed therein. Each bore hole 14 is drilled from the interior of an excavated surface toward the side of the natural ground. The bore hole 14 has a water-collecting pipe inserted therein, which is obtained by entwining fibers at random with the intersections of the fibers being bonded, to form a three-dimensional mesh, and then constituting a hollow pipe body of the three-dimensional mesh. Fitted at the periphery at an end of the water-collecting pipe on a rear end side is a connecting sleeve formed of a hollow cylindrical steel pipe. Furthermore, connected to the opening end of the sleeve on the side of the natural ground is one end of a suction hose 26, which has the other end thereof connected to a collective connector 28. The collective connector 28 communicates with a vacuum pump 32 via a pipe arranged therebetween.
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