| 摘要 |
PROBLEM TO BE SOLVED: To provide a side ditch with a slit which improves the product strength by making the upper wall of the side ditch thin and which can turn the concrete quantity to be used therefore to bottom wall side to increase a product strength without enhancing the production cost, without any fear of breakage of slits or cracking at the lower ends of both lower ends of the wall, and facilitate haulage. SOLUTION: The side ditch with a slit has a substantially square columnar shape, and provided with a hollow space in the axial direction. The hollow inside communicates with the outside through the slit which is formed straightly in the axial direction at the upper face. Columnar notches ate formed downward perpendicularly at the central position in the breadthwise direction of the sliter at the upper face and a metallic spacer tool having a cylindrical pipe shape is detachably fitted in the notch as a feature.
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