新疆大西沟水库坝基异常气体分析

Study on abnormal gas in dam foundation of Daxigou Reservoir

为了查明大西沟水库坝基异常气体的来源,了解是否存在有害气体,并判断其对工程的影响。采集溶有异常气体的水样和坝基岩样,分别进行了相关水化学分析试验和岩石磨片鉴定。结果表明:异常气体为硫化氢(H2S),气体来源具有热化学还原反应的成因条件或存在微生物硫酸盐还原的可能;溶于水中的气体对钢筋混凝土、预应力混凝土有强腐蚀性,对水泥砂浆和素混凝土有弱腐蚀性。

In order to investigate the source of the abnormal gas in the dam foundation of Daxigou Reservoir and find out wheth- er there exist harmful gases and determine the causes of the abnormal gas and its impact on the engineering project, the water samples containing abnormal gas are collected for water - related chemical analysis and the rock samples of dam foundation are collected for rock grinding identification. The abnormal gas of dam foundation is identified as Hydrogen Sulfide （H2S） Gas, which is caused by thermochemical reduction reaction and slfate reduction of microorganism. The analysis on the groundwater in the dam foundation reveals that the dissolved H：S is strongly corrosive to the reinforced concrete and the pre -stressed concrete and slightly corrosive to the cement mortar and the plain concrete.