某水利枢纽区渗漏性状分析与防渗处理建议

Analysis on seepage behavior of a water control project and suggestion on its anti-seepage treatment

某水电站建成蓄水后,量水堰便出现了流量较大的渗漏,且随着库水位的抬升,渗漏量呈现出逐渐增大的趋势。此外,渗水水温高于库水,具温水的特征。为了对渗漏原因与渗漏通道进行分析,采用水文地质测绘、水文地质钻探、压水试验、水质全分析、孔内电视、地下水观测等综合勘察方法查明了坝址区岩体透水性、地下水渗流场、渗水特征及水化学特征。结果表明:早期渗水由浅表循环的冷水和深部循环之热水混合而成,且以冷水为主;坝基及绕坝渗漏通道以岩层层面和两组节理为主,属裂隙型渗漏。在此基础上,利用回归分析预测得到库水达正常蓄水位时,量水堰渗漏量为1 728.40 L/s,据此,提出了防渗处理建议。经防渗处理后,库水位达正常蓄水位时,渗漏量减至270 L/s,防渗效果明显。

After the completion and impoundment of a hydropower station,the seepage with large flowrate occurs at its measuring weir and rises along with the water level of the reservoir with a trend of gradual increase. Moreover,the water temperature of the seepage is higher than that of the reservoir with the characteristics of warm water. In order to analyze the seepage causation and the passage,the rock permeability,groundwater seepage field,seepage characteristics and hydrochemicalcharacteristics within the dam site are ascertained with the comprehensive reconnaissance methods such as hydrogeological mapping,hydrogeological drilling,pressure water test,complete water quality analysis,borehole TV,groundwater observation,etc. The study shows that the early seepage is mixed by both the shallow surface circulating cold water and the deep-circulating hot water and is mainly the cold water. Furthermore,the seepage passages under the dam foundation and around the dam body mainly consist of rock layers and two groups of joints and belong to fissure seepage. On the basis of this,it is predicted through the relevant regression analysis that the seepage at the measuring weir is to be 1 728. 40 L/s,when the reservoir water reaches the normal storage level. Thus,the relevant suggestions on the anti-seepage treatment are put forward. Consequently,the seepage is reduced to 270L/s,when the reservoir water reaches the normal storage level.