| 摘要 |
PROBLEM TO BE SOLVED: To provide a side ditch with a slit, both the side surfaces of which are made thin, which can reduce the manufacturing cost by reducing the amount of concrete to be used, which eliminates the fear of breakage of the manufactured slit, and which facilitates transportation and laying work by virtue of weight reduction even when transported and laid. SOLUTION: This square column-shaped side ditch 1 with the slit, in which a hollow passage 2 is provided in the direction of an axial center; a top surface is provided with the slit 3 which makes the hollow passage 2 communicate with the outside, is characterized in that both the side surfaces of the side ditch 1 are formed as thin side surfaces; and a wedge-shaped interval maintaining implement 4 is detachably attached to the slit 3 at an interval. COPYRIGHT: (C)2004,JPO&NCIPI
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