龙凤山水库土石坝渗流混水现象研究

龙凤山土石坝在运行的很长一段时期内，坝后排水沟出现严重的混水现象，该现象白天呈周期性变化。利用原子吸收法和X-荧光光谱分析法，对坝后排水沟中的水及析出物进行化学成分分析，研究坝基析出物化学成分的演变规律。研究表明，水质中富含Ca，析出物中富含Fe和Mn。在坝基地下水渗流过程中，地下水与坝基岩石产生物理化学作用，从而导致化学潜蚀。地下渗流水的化学潜蚀作用与坝基岩石性质密切相关。在基性类岩石中，由于富含铁、锰等深色元素，在酸性环境中很容易迁移，因而排水沟中出现Fe2O3和MnO2絮凝状沉淀物，导致排水沟出现混水现象。

Research on seepage muddle water phenomena at earth-rock dam for Longfengshan Reservoir

Longfengshan Eeath-Rock Dam has running for a long time; the muddy water phenomenon has occurred seriously in the gutter. The muddy water phenomenon changed cyclically during the day. The atomic absorption spectrometry and the X-fluorescence spectrometry has been developed to analyze the chemical composition of water and precipitates in the drainage. The chemical constituents’ evolution law of the dam foundation precipitates is researched. Research results show that the water is results rich in Ca and the precipitates are rich in Fe and Mn. In the period of groundwater seepage in the dam foundation, groundwater has physico chemical reaction with the rock foundation, leading to chemical corrosion. The chemical corrosion of groundwater seepage is closely related to the nature of the foundation rock. Basic rock category, because of the rich in iron, manganese, and other dark elements, was prone to migrate in the acidic environment.Fe2O3 and MnO2 flocculation-like sediment would appear in the gutter,resulting in the muddle waters phenomenon in the gutter.