中文摘要：

在面板完好的条件下,面板堆石坝坝体的渗透稳定性很容易满足要求;在面板止水破损和面板失效的不利条件下,过渡区的渗流控制作用对于大坝的渗透稳定性具有关键意义。结合水布垭大坝实例,通过层间系数的分析,认为必须通过试验研究过渡料对垫层料的反滤保护作用。通过反滤试验研究了水布垭全级配过渡料对垫层料的反滤效果和渗透变形规律,结合已发表的研究成果进行综合分析,探讨了过渡区的渗流控制作用机制：过渡料与主堆石区一起,可对坝体起到很好的排水作用;在面板止水破损和面板失效的不利条件下,垫层料内部可能会发生颗粒迁移和内部结构调整,但在过渡料的反滤保护作用下可维持渗透稳定;初次遇到这种工况时,过渡区自身会有少量细粒流失,但其骨架将维持稳定,借助于主堆石区的支撑作用,过渡区将继续发挥其反滤和排水的双重作用。

英文摘要：

For concrete faced rockfill dams,while the concrete face functions normally,the seepage stability of the dam is satisfied;while the concrete face cracks locally or does not work properly,it is pivotal for the transition zone to control seepage field in the dam and to keep seepage stability.Taking the concrete faced rockfill dam of Shuibuya Hydropower Station for example,the coefficient between cushion layer and transition zone is analyzed;it is indicated that tests are necessary to study filtering and protection of transition zone for cushion layer.Tests are performed with cushion layer and transition zone material of whole size gradation;and the seepage deformation and filtering effect is studied.Synthesizing the test results and the results in author＇s papers published already,the mechanism for the transition zone to control the seepage field in superhigh concrete faced rockfill dam is concluded.The transition zone,together with the main rockfill zone,could drain efficiently water from cushion layer.Ones the concrete face cracks or does not work properly,the interior structure of the cushion layer would change with the fine particles moving downward along water flow.Fortunately,with the protection of transition zone,the particles would stop around the interface between the two zones;and seepage stability of the cushion layer would be maintained.In the first abnormal experience,some fine particles would move out from the transition zone;but the framework of the material would remain stable.With the support of the main rockfill zone,the transition zone could continue to function at both aspects of filtering and drainage.