小湾水电站拱坝设计

Design of Arch Dam for Xiaowan Hydropower Station

小湾拱坝是该工程设计的难点之一，坝高２９２ｍ，河谷较宽，坝顶弦长８２６ｍ，地震设防标准高，设计加速度为０．３０８ｇ；坝址区分布有多条回级以上断层及蚀变带，岩体卸荷发育深．坝体的应力及变位和两岸坝肩岩体的变位都达到了相当高的量级，拱坝设计中遇到的许多问题已超出了现行拱坝设计规范的范围．在这些特定的条件下，设计出一个合理安全的拱坝是相当困难的．本文简要介绍了小湾拱坝在可行性设计阶段（原称初步设计阶段）的体形优化、坝体应力分析、坝肩岩体稳定分析，以及基础处理等方面的设计内容．

Arch dam is one of the design difficulties to Xiaowan Project. The 292 m high arch dam with its crest arc chord 826 m long is located in a wide valley. The standard of earthquake-proof is high,earthquake acceleration is 0. 308 g,Many faults which are more than grade Ⅲ and many altered belts spread under the dam site,rock mass is of deep develOPed relief state. Stress and strain of the dam as well as the strain of rocks under the abutments on both banks reach rather high order. Many problems go beyond the scope of arch dam design at present. It is very difficult to devise a safe and reasonable arch dam under the particular conditions. This poper deals with the shape optimized,stress analysis of the dam body,rock stability of abutment and foundation treatment during the feasibility design stage (i. e the original preliminary design stage)of Xiaowan Arch Dam.