某平原水库坝基渗漏成因分析

Causes Analysis of Seepage in the Dam Foundation of Plain Reservoir

针对某平原水库渗漏现象,采取安全监测、地质勘探和无损探测及数学模型等多种手段,对比了蓄水前后库周地下水渗流场差异,查明了坝基含水层中弱透水层连续性及缺失段,高密度电阻探测结果说明坝基含水层较深,应用坝体坝基及库周观测孔实测值开展了水库三维渗流反演计算,在此基础上对高水位水库大坝三维渗流场进行了预测计算。综合分析成果,揭示了水库渗漏成因,解释了库周浸没现象。结果表明,因地基相对隔水层渗透性大且有缺失段导致防渗体系不健全是水库渗漏主要原因,同时库内外广泛分布且封堵不彻底的农用机井缩短了有效渗径,增大了水库渗漏量。

Aiming at the leakage phenomenon of a certain plain reservoir, various means, such as safety monitoring, geological investigation, nondestructive detection, mathematical model, were adopted to compare the difference of groundwater seepage field around reservoir before and after impoundment. The continuity and missing segment of weak permeability in aquifer of dam foundation were found out. The high density resistivity detection results show that the aq- uifer in dam foundation is deeper. The observed values of reservoir observation hole and dam foundation were used to car- ried out reservoir seepage inversion analysis. The 3D seepage field of high water level reservoir dam was predicted. Com- prehensive analysis results reveal the causes of reservoir leakage and explain the phenomenon of reservoir submersion. The results show that the main reason for reservoir leakage is the lack of seepage prevention system due to the large permeability and missing segments of the relative aquifuge in foundation. At the same time, the wide distributed incomplete sealed agricultural pumping wells shorten the effective seepage path and increase the leakage of reservoir.