水布垭面板堆石坝过渡料设计及其渗透变形特性研究

Study on Design Requirements and Seepage Deformation Characteristics of Transition Zone Material for Shuibuya Concrete Face Rockfill Dam

对于水布垭水电站这样的超高混凝土面板堆石坝,过渡料的渗透稳定和渗流控制作用非常重要。回顾了水布垭大坝过渡料设计要求的研究确定过程;介绍了采用专门研制的大型仪器和供水供压系统,首次针对全级配过渡料开展的渗透变形试验工作。对比试验成果、设计要求及预测的大坝运行状况,认为:过渡区渗透性下限在设计要求之内,上限超过设计上限一个量级,排水性好于设计要求;在面板完好的正常运行条件下,过渡区的渗透稳定性可以满足要求;在面板失效且水库仍然维持设计水位的极端条件下,过渡区的细料会流失,内部结构失去稳定,但是在主堆石区的支撑下骨架仍将稳定。

The seepage stability and the role of the transition zone material to control seepage field is very important for the super high concrete faced rockfill dam （CFRD） of Shuibuya Hydropower Station. The study process of its design requirements was reviewed. With big seepage test apparatuses and water supply system set up specifically for this project, seepage deformation tests were performed for the first time on the whole size gradation curves of the transition material. The test results were compared with the design requirements and the expected situation of the seepage field in the dam. The lower limit of the material permeability coincides with the design, and the upper one would exceed the design with one magnitude. So the transition zone will drain more quickly than design. Under the normal condition that the concrete face functions well, the seepage stability of the transition zone will be satisfied. While the concrete face cracks locally or does not work totally and reservoir water level remains at design water lev- el, fine grains would be driven out from the transition zone. Then the interior structure of the material would be unstable, but the framework of the transition zone would remain stable with the support of the main rockfill zone.