| 摘要 |
PROBLEM TO BE SOLVED: To provide an impervious wall capable of cutting off a bleeding channel generated around a tunnel, by restraining looseness of base rock caused by construction. SOLUTION: This impervious wall is constructed in a shaft 4, and has a continuous groove 10 excavated outward so as to separate from the shaft 4 for turning downward from a water cut-off plug 6 in the shaft 4. Highly concentrated bentonite slurry 11 is filled inside the continuous groove 10, and the substantially umbrella-shaped impervious wall 7 is formed. The impervious wall 7 is constituted by being joined in close contact with the outer periphery of the water cut-off plug 6 formed of a bentonite block arranged in the shaft 4. COPYRIGHT: (C)2006,JPO&NCIPI
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