Influence of different structural installation conditions on the progress of wear of wooden check dam elements

Abstract

This study was constructed in 1953 with the aim of clarifying the effects of differences in structural installation conditions, such as the downstream slope and the installation of concrete dams directly above, on the degree of wear of wooden check dam elements. A wear survey was conducted on the wooden check dam, and wear was compared with that of the wooden check dam located downstream. As a result, in the second to fourth tier counted from the top, there is a difference of nearly two times in the average value of the residual ratio of the cross-sectional area, and a small downstream slope affects the progress of wear. Considering the fact that sand and gravels with large particle sizes are suppressed at the time of water discharge by the concrete dam directly above, the wear of the elements is 1–5 years with the flow of water containing fine sediments in non-flooding. It was considered to be progressing in the range of 2 mm/year. The number of years of loss of element diameter is estimated to be up to 100 years in the case of an element diameter of about 200 mm, which is not largely inconsistent with the actual condition of the wooden check dam, which has been destroyed for 98 years in this survey site.