环形预应力锚索在二滩水电站拱坝中孔结构上的应用

二滩水电站拱坝泄洪中孔出口弧形工作闸门支承结构的预应力锚索由直线形改为环形，锚索穿过预埋在坝体内的环形护管安装，达到了不削弱坝体结构，又使其周围应力趋于均匀的目的。但锚索长度增加１倍以上，单束长达７４ｍ，且为环形，施工难度大。为此，在设计与施工技术上进行了一系列开拓性的工作以保证工程质量，现已完成６个中孔的７２束环形预应力锚索的施工。

Application of ring pre-stressed anchorage cable in the hole structure of Ertan Arch Dam

The pre stressed anchorage cables in the support structure of the radial working gate of flood releasing hole in the arch dam of Ertan Hydropower Station are changed from straight into ring. The cables go through the ring protective tube which is pre buried in the dam body, so that it could make their surrounding stresses be well distributed under the condition that the structure of dam body cannot be weakened. Because the length of the cable doubles (up to 74 m for single bunch cable) and is ring, the cable construction is very difficult. As a result, the design and construction technologies have been improved greatly in order to guarantee the quality of the project. Up to now, the construction of 72 bunches of ring pre stressed anchorage cable has been completed.