平原水库土工膜防渗特性分析

复合土工膜防渗措施是解决平原水库渗漏问题的有效手段。为了研究平原水库土工膜防渗特性,以山东省清源湖水库为例,采用数值模拟与现场实测相结合的方法,建立了基于饱和-非饱和渗流微分方程的土工膜防渗围坝渗流有限元分析模型,并将计算结果与实测数据进行了对比。研究表明铺设土工膜防渗后,非饱和区域显著增加,忽略非饱和区域会使得渗漏量计算值偏小、浸润线及溢出点高度计算值偏低,令设计者低估渗漏的严重程度,不利于坝体的渗流稳定;土工膜缺陷因素(如缺陷的位置、尺寸、数目及与其下垫层的接触情况)对渗漏量和围坝浸润线亦有较大影响;土工膜缺陷及土工膜与下垫层的接触情况主要取决于施工质量,在施工期对土工膜缺陷进行严格控制,可有效减少渗漏量,对平原水库的安全运行具有十分重要的意义。

Anti-seepage Performance of Geomembrane Used in Plain Reservoir

Compound geomembrane is an effective measure for the seepage control of reservoir in plain area. In this research, numerical simulation and field test are employed to analyze the anti-seepage performance of geomembrane for plain reservoir. A finite element analysis model of geomembrane seepage is established based on the differential equation of saturated-unsaturated seepage. The Qingyuan Lake Reservoir in Shandong Province is taken as a case study. Comparison between simulation result and measured result shows that non-saturation region increases significantly in the presence of geomembrane. The non-saturation region should not be ignored, otherwise the calculated results of leakage flux, seepage line, as well as overflow point height would be lower than measured result, which makes engineers underestimate the severity of seepage. Moreover, factors of geomembrane defect (such as location, size, number and contact situation with the under layer) also have large impact on fluxes and seepage lines. Geomembrane defects mainly depend on the construction quality, so it is very important for the safety of the reservoir to control the geomembrane defects strictly.