面板堆石坝垫层渡汛离心模型试验研究

Centrifugal model tests on the flood retaining scheme using cushion layer of a slab faced rockfill dam

西北口水库大坝是我国建设的第一座百米级钢筋混凝土面板堆石坝,其百年一遇洪水渡汛水位降落幅度21.63 m,水位骤降速度最大可达3.65 m/h。面板尚未浇筑前的堆石坝体需临时拦洪渡汛,坝体垫层既起面板垫层作用,还要保证堆石坝体安全渡汛,水位骤降对垫层将产生拖拽力作用,影响到垫层的稳定性。本文通过面板堆石坝垫层渡汛离心模型试验,对不同渗透性垫层安全渡汛进行了试验研究,试验研究成果被西北口面板堆石坝工程施工期安全渡汛设计采纳,为面板坝工程建设特别是施工期安全渡汛提供了技术支撑。

Xibeikou concrete faced rockfill dam is the first case of such a type of dam with a height of 100 meters.The drawdown of reservoir level prior to a flood with a reoccurrence of 100 years reaches a magnitude of 21.63 m,and the maximum rate of drawdown is about 3.65 m/h.Before casting the concrete slabs,the flood should be retained by the filled dam.The cushion material,which serves as a foundation of concrete slabs and is responsible for the safety during flood season,is subject to the drag of seepage force during drawdown of the reservoir level,and its stability needs careful verification.In this study,centrifugal model tests were conducted on flood retaining schemes using cushion materials with different permeability.These experimental results have been adopted in controlling the flood during construction of the dam,and have provided technical support for the safety of dam during flood seasons.