高土石坝大交角挑流消能水垫塘优化布置

Optimizing layout of plunge pool for a high earth dam with large angle of ski-jump energy dissipation

通过如美水电站整体模型试验,从水流流态、水垫深度、动水压力、下游河道流速分布等特性,对比研究了增设二道坝和降低底板高程两类优化方案。结果表明,大交角挑流消能水垫塘下游增设二道坝,其效果与二道坝高度、泄量、河谷宽度等密切相关,会恶化出流与下游河道的衔接;降低水垫塘底板高程对下游衔接影响较小,且可有效增加水垫深度,降低水垫塘临底水力指标。

Through the integral model test of the Rumei Hydropower Station,characteristics of flow pattern,water cushion depth,hydrodynamic pressure and velocity distribution at the downstream channel were studied.Optimization schemes of adding a subsidiary dam and lowering the bottom elevation of the plunge pool were compared.The results show that the effect of adding a subsidiary dam downstream the plunge pool is closely related to the height of the subsidiary dam,the discharge and the width of the valley,and can worsen the joint of the outflow and the downstream channel.Lowering the bottom elevation of the plunge pool has little influence on the downstream connection,and it can effectively increase the depth of the water cushion and reduce the near-bottom hydraulic indexes of the plunge pool.