摘要
为了研究导流洞围堰残梗高程对截流难度的影响,以雅砻江两河口水电站截流为例,对截流流量为550、364m3/s时不同的围堰残梗高程进行对比试验,量测了戗堤龙口和围堰残梗处各项水力特性指标,分析了不同的围堰残梗高程对截流的影响。结果表明,随着围堰残梗高程的增加,龙口水力指标逐渐增加,增大了截流难度;残梗处水流流态由淹没出流转变为自由跌流,且当水流流态为淹没出流时,残梗高程增加,对截流影响不大;水流流态为自由跌流时,残梗高程增加,会显著增加截流合龙难度;截流流量减小时,围堰残梗对截流的影响增大。实际施工过程中,当截流流量为550m3/s,残梗高程为2 604、2 605m时对截流的影响变化不大,考虑到安全、经济、施工工期等因素的影响,建议将围堰残梗高程拆除至2 605m即可。
In order to find out the influence of height of cofferdam stubble on difficulty of river closure, taking Liang- hekou hydropower station for an example, comparative experiments of different height of cofferdam stubble were conduc- ted under the flow of 550 m3/s and 364 m3/s. The hydraulic characteristic indexes at the closure gap and the cofferdam stubble were measured. The influence of different stubble cofferdam height on river closure was analyzed. The results in dicate that the hydraulic index of closure gap increased with the increasing of residual-dyke＇s height and the difficulty of river closure; the flow pattern changed submerged flow into free drop at the residual-dyke. In addition, under the sub merged discharge, the increase of residual-dyke＇s height only had little influence on the river closure; while under the free drop, the increasing residual-dyke＇s height enlarged the difficulty of closure. Besides, with the reduction of water dis- charge, the influence of residual cofferdam on the river closure was enlarged. In reality, considering the factors of safety, economy and construction duration, when the closure flow was 550 m3/s and the residual-dyke＇s height was 2 604 m or 2 605 m, the height of cofferdam stubble was advised to dismantle to 2 605 m.
出处
《水电能源科学》
北大核心
2015年第7期117-120,100,共5页
Water Resources and Power
关键词
围堰残梗
截流
自由跌流
淹没出流
residual cofferdam
river closure
free drop
submerged discharge
