| 摘要 |
PROBLEM TO BE SOLVED: To provide a U-groove having the upper parts of right and left side wall parts capable of developing a high rigidity against a soil pressure applied thereto from various directions in the U-groove usable for agricultural irrigation channels, industrial channels, drainage channels and general civil engineering channels and drainage channels. SOLUTION: Thus U-groove formed with hard synthetic resin or fiber- reinforced resin is formed in a corrugated shape by continuously forming recessed line parts and projected line parts alternately in the longitudinal direction of the groove. The recessed line parts and projected line parts are continuously formed ranging from the bottom wall part of the U-groove to the upper ends of the right and left side wall parts, and a reinforcement wall closing the recessed line parts and extended outward is continuously formed at the upper ends of the right and left side wall parts in the longitudinal direction of the groove. COPYRIGHT: (C)2003,JPO
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