| 摘要 |
PROBLEM TO BE SOLVED: To enable cleansing processing of placed concrete in an initial stage of hardening of the same. SOLUTION: A water leading apparatus has an expandable water conduit 22, a hydraulic jack 24, and a raw water conveying portion 26. The water conduit 22 is a double pipe consisting of an inner pipe 22a and an outer pipe 22b, and both the edges thereof are opened. The raw water conveying portion 26 has a casing 26a, a filter layer 26b, and an impervious sheet 26c which is hot-water soluble. The casing 26a is of a box shape, and has an open end thereof, which is arranged so as to face an excavated wall surface on the side of natural ground A. The casing is provided with a permeable plate 26e which defines a passage space 26d above the bottom thereof. The filter layer 26b is housed in the casing 22a in a manner being mounted on the permeable plate 26e. The hot-water soluble impervious sheet 26c is dissolved when brought in contact with hot water at a predetermined temperature.
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