同位素方法在判定某水电站坝址河床承压水补给源中的应用

某水电站坝址工程勘察论证时,河床部位钻孔揭示存在基岩裂隙性承压水,判定其补给来源对大坝坝基采取相应的防渗工程措施具有关键技术意义.依据稳定同位素和放射性同位素能对水起着标记作用,通过承压水等天然水同位素,包括氘(δD)、氧(δ18O)、氚(3H)、硫(δ34S)的测试和成果分析,为判定河床承压水补给来源提供了有力的证据.研究结果表明:坝址河床承压水来源于左岸大气降水入渗,补给源高程在1 000～1 350m之间.同位素方法在该水电站坝址河床承压水补给源研究中获得了满意的效果.

Application of Isotopes Method on Judging Supplied Source of Confined Groundwater in Riverbed at the Dam Site of a Hydropower Station

There are confined groundwaters of bed rock fissures exposed by boreholes in riverbed during engineering investigation at the dam site of a hydropower station.Judging their supplied source has critical technology meaning to corresponding anti seepage engineering measures that are taken in the dam foundation.According to symbol function of stable and radiation isotopes for waters,they provide powerful evidence for judging supplied source of confined groundwaters in riverbed by tests and results analysis of isotopes of natural waters containing confined groundwaters samples,the isotopes include δD,δ18O,3H and δ34S.The research results indicate that confined groundwaters in riverbed root in infiltration of atmospheric rainfall,and their supplied source elevations are between 1000m and 1350m.Isotopes method is obtained satisfactory effect on research of supplied source of confined groundwaters in riverbed at the dam site of this hydropower station.