انتقال رسوب غير چسبنده در سازه هاي سنگريزه اي با استفاده از مدل تلفيقي يك بعدي و آناليز ابعادي

Non-Cohesive Sediment Transport Capacity in Detention Rockfill Using a Combined 1D Model and Dimensional Analysis

Pure rockfill dams have been found specific attention in watershed management and flood control, recently. In addition to hydraulic specific features, one of the important advantages of these structures is their consistency with nature and environment. Normally, floods are accompanied with high sediment loads which may enter the body of dam. When flow through dam body governed by hydraulic gradient higher than the critical one, sediment will pass through and be transported downstream the dam. If sediment load transported through rockfill dam is more than sediment transport capacity of downstream channel, then erosion may occur downstream and if less, excess sediment load will be settled down. Therefore, it is important to determine sediment transport capacity of flow through rockfill dams before building them. For this purpose a 1-D model for flow through rockfill dam accompanied with sediment transport relationship in coarse porous media (rockfill) has been developed. The rockfill dam used in the experiments was consisted of a rectangular block of 600 mm long, 300 mm wide and 300 mm high. The experiments were conducted for two d50 rockfill (14.5 and 21 mm) three d 50 sediment sizes (0.256, 0.362 and 0.512 mm) d 50 , and five flow rates (5 to 13 1/sec). The refered relationship includes some coefficients related to the rockfill media and its flow turbulence which need to be identified. In this regard, experiments have been conducted. The results of the model compared to the observed experimental data have been shown to be reliable.