中文摘要：

国内外的工程实践、计算分析、模型试验表明，高拱坝，特别是坝高超过200m的特高拱坝，坝踵部位因施工期属于强约束区，运行期应力复杂，常常难以确定是否会在基础或坝体部位出现裂缝，而坝踵部位的裂缝有可能会因为高水压力作用发生水力劈裂而进一步扩展，影响拱坝的正常运行。本文提出了在高拱坝坝踵上游面强约束区设置柔性防渗体系的新思路，提出了大型框架式仿真试验方法，可以模拟300m高水压下的柔性材料防裂漏水问题，并对所推荐的材料进行了仿真试验论证。建议的材料和方案已应用于小湾拱坝工程。

英文摘要：

The experience of engineering practice, numerical analysis and model test shows that the occurrence of cracking in arch dam heel, especially for high arch dams, is hard to predict, because this location is under strong constraint during construction and its stress is very complicated after the dams put into operation. The cracks may further expand due to the hydraulic split action of high water pressure. To solve this problem, a new idea of using flexible water tight system to prevent the high water pressure entering the cracks is suggested. A conceptual model test is carried out to verify the feasibility of this new measure. The water head of the model test is as high as 300m. The test result shows that the water tight system is reliable and the material suggested by the authors can be used in engineering practice.