云南省巧家县白鹤滩水库建成后,位于金沙江右岸富水冲洪积扇内的白鹤滩水电站移民安置用地中,钻孔揭露大量空腔,为了探究该地块地下水渗流规律及空腔连通特征,采用示踪试验进行研究。本次示踪试验历时2 d,以荧光素钠为示踪剂,采用V1600型可见分光光度计在波长为495 nm时检测样品中荧光素钠吸光度,根据决定系数R²=0.945 1的荧光素钠浓度-吸光度标准曲线换算荧光素钠浓度,获得单峰型荧光素钠浓度时间序列曲线。通过示踪试验揭示了场地区地下水整体由东向西流动,往区域最低排泄基准面金沙江排泄。场地区有2个地下水主要径流通道:①钻孔BK4163—BK4114—BK486方向;②钻孔BK4163—BK4224方向。同时根据 Qtracer2计算模型将示踪剂浓度曲线进行了定量分析,得出了过水通道的结构参数和水力学参数。

After the completion of Baihetan reservoir construction in Qiaojia County, Yunnan Province, a large number of cavities were exposed by boreholes in the resettlement land of residents, which is located in the water-rich alluvial fan on the right bank of Jinsha River. A Two-day tracer test was carried out to explore the groundwater seepage law and cavity connection characteristics. Fluorescein sodium was selected as tracer, and the V1600 visible spectrophotometer was used to detect the absorbance of sodium fluorescein in the sample with a wavelength of 495 nm. The absorbance of sodium luciferin concentration was converted according to the standard curve of sodium luciferin concentration versus absorbance with R²=0.945 1. The time series curve of sodium fluorescein concentration with single peak was also obtained. The tracer test unveil that groundwater flows from the east to the west in general and discharges to the Jinsha River at the lowest datum level of regional discharge. Two main channels of groundwater runoff were revealed in the field area: borehole BK4163-BK4114-BK486 direction and borehole BK4163-BK4224 direction. In addition, the structural parameters and hydraulic parameters of runoff channels were acquired via quantitative analysis of concentration curve of the tracers by using Qtracer2 calculation model.