| 摘要 |
PURPOSE:To repair a flexible film without damaging its strength by using a system in which the abrasion losses of the flexible film can be detected before the abrasion losses reaches a strength member. CONSTITUTION:An abrasion detection layer 4 is provided to the outermost film layer of a flexible film rising and falling dam provided across a river on the river bed, by which the degree of the abrasion can be soon observed and repairing can be attained before the abrasion damage reaches cloth or cord layer 1 as resinforcing members. In this case, the abrasion detection layer 4 may be provided over the whole surface of a carpet or on the portion where abrasion is great, and a thin layer tinted differently from the outermost film layer 3 may be used. In this way, as the abrasion proceeds, different-color layer or cloth layer appears and thereby the degree of abrasion can be judged. |
