| 摘要 |
PURPOSE:To quickly damp the energy of shooting flow to streaming flow by a method in which two kinds of more of columnar concrete blocks having vertical sides, joined horizontal cross sections, and greatly different heights are alternately laid closely to each other on the river bed. CONSTITUTION:An overflow port 2 is provided on the center of the upper end of a permeable dam 1, through which great amounts of water flows down to become a shooting flow on the bed protective work 3. In the bed protective work 3, high blocks 6 and low blocks 7 are alternately set closely to each other in a checkered form, and the horizontal cross section of the blocks 6 and 7 is shaped into a joined form. The river bed can thus be closely covered to prevent the occurrence of scouring of the basal portion of the river bed. The partial exchange of these blocks can be easily made even after the completion of the block construction work. |
