宜兴抽水蓄能电站上水库主坝下游堆石区设计优化

Design optimization of downstream rockfill zone in main dam of upper reservoir of Yixing Pumped Storage Power Station

针对宜兴抽水蓄能电站上水库主坝建在倾斜基础面上的特点,为避免下游堆石体后期沉降过大,对下游堆石区设计进行了优化。下游堆石区改为主堆石Ⅱ区,并将高程426.50 m以下的贴坡堆石体设计为"增加变形模量区",其压实标准高于主堆石区;坝体下游堆石填筑施工超前于上游堆石。原型观测数据和反演分析成果表明:"增模区"变形模量显著提高,主坝变形很小;下游堆石区的优化对于减少坝体不均匀沉降、减少上游面板开裂,以及减少堆石体对下游重力挡墙的土压力起到了重要作用。

With regard to the main dam of the upper reservoir of Yixing Pumped Storage Power Station built on an inclined bedrock surface and in order to avoid large post settlement of the downstream rockfill, the downstream rockfill zone was optimized. The downstream rockfill zone was treated as the second main rockfill zone, and the rockfill zone below the elevation of 426.50 m was designed as the ＂increased modulus zone＂ where the index of compaction was required higher than that of the main fockfill zone. Meanwhile, the filling construction of the downstream rockfill began before that of the upstream one. The data of prototype monitoring and the results of back analysis indicate that the deformation modulus in the ＂increased modulus zone＂ obviously increases, and the deformation of main dam is small. The design optimization of the downstream rockfill zone plays an important role in reducing the differential settlement of dam body, the cracks of upstream concrete face slabs and earth pressure of rockfill on the downstream retaining walls.