| 摘要 |
PROBLEM TO BE SOLVED: To provide a highly reliable seal construction without making a vertical shaft large. SOLUTION: A cavity portion 11 is provided inside a wall body excavated with a side wall, and a tube having a tube main body and a cushion material 13 is provided in this cavity portion. Position of this cavity portion 11 is determined so as to cut the cushion material 17 by the side wall, piping 15 is connected to the tube main body, and the other end of this piping 15 is connected to an air or water supply source (not shown in Figure) provided at the inner side of the side wall 3.
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