水电站工程建设对河道泥沙含量变化的影响——以金安桥水电站为例

摘要

During the construction of hydropower station, the waste soil and residue were directly abandoned in the river way, and altered the sediment amounts in the construction areas and downstream rivers.Taking Jin'anqiao hydropower station as example, we analyzed the change dynamic of sediment in the disturbed river through the hydrometer method. The results are following: (1) the sediment amount changed greatly in different construction stages. In the early and late construction stages, the sediments were 3.99and 4.55 times more than the average value of many years respectively; (2) the upstream and downstream sediments varied with rainfall and construction progress, in 2005, the downstream sediment was 1.99％lower than the upstream sediment, however, from 2006 to 2008, the downstream sediment were 24.58％,27.19％, and 375.51％ greater than the upstream sediment, respectively.%由于水电工程建设的特殊性,导致弃土弃渣直接进入河道现象比较严重,致使施工区及以下河道泥沙含量发生显著变化,严重影响库区使用寿命和河道行洪安全.本文运用比重法对金安桥水电站工程建设过程中受影响河道的泥沙含量进行测定,以分析其动态变化特征及控制措施.结果显示:(1)施工初期和末期的工程开挖对河道泥沙含量的贡献率较大,分别是多年平均值的3.99倍和4.55倍;(2)年内河道上下游断面泥沙含量变化也较大,2005~2008工程区上下游河道断面泥沙含量变化差异性较大,下游泥沙含量分别比上游高出-1.99 %、24.58%、27.19%和375.51%.