大古水电站坝前排沙运行方式与排沙漏斗形态

Desilting operation modes and sand funnel patterns in front of Dagu Hydropower Station Dam

为给实际工程排沙设施的设计和布置提供依据,基于1∶60整体模型,根据淤积泥沙扬动流速相似原理,试验研究大古水电站2条排沙廊道和1个底孔在不同运行方式下坝前库区的排沙效果和排沙漏斗形态。结果表明:排沙洞开启顺序对最终排沙效果影响不大;深水条件下,坝前排沙漏斗形态主要受泥沙特性决定,非黏性沙的排沙漏斗坡度接近于淤积泥沙水下休止角;大古水电站排沙设施的设计方案具备保证电站进水口"门前清"的条件。

Based on the similarity criteria of incipient velocity,an experimental study is performed on a 1∶60 overall physical model to study the sediment flushing effects and sand funnel patterns of two desilting galleries and one bottom tunnel under designed operating conditions to provide a basis for the design and arrangement of the desilting facilities in front of the Dagu Hydropower Station Dam.The results show that the ultimate desilting effect is less affected by the operating order of the desilting tunnels.The patterns of sand funnels are mainly determined by the sediment property,and the slope of the sand funnels is close to the underwater repose angle of non-cohesive sediments under deep reservoir water level.The design scheme for the desilting facilities in Dagu Hydropower Station guarantees the condition of clear in front of the hydropower intake.