秋田県における木製治山ダムの開発に関する取組み

抄録

In Akita Prefecture, to promote the demand expansion of the Japanese cedar produced in Akita Prefecture and to activate the local areas by centering timber industry, various civil engineering structures used timber have been proposed and developed, and have been actually constructed. Wooden check dam is one of these, there are two kinds of wooden check dams called “Akita standard”. One of which is “all wood type” dam composed only wood members and lag screws, and usage rate of timber is up to 90%. Another is “hybrid dam” packed the thinned wood and gravels in the steel flexible frame, and usage rate of timber is about 80%. In this study, we presented the details of all wood type wooden check dam and hybrid type. In all wood type wooden check dam, we reported results of the strength test of joint used lag screw and failure test of real-size dam specimen, which were conducted before construction, and monitoring study at construction site. In addition, we accessed the strength property, usage rate and cost performance of each Akita standard dam by comparing the crib dam which ever have spread in the whole country. In the failure test, it was shown that the specimen have safety rate 10 for the design load. With regard to monitoring study, from actual water level inside dams, it found that phreatic line was lower than design position. In comparison with the crib dam, although for used amount of timber Akita standard dam was very effective, for cost there was no difference.