複合阻水層之滲流率

Abstract

在地工止水膜產生破洞時的滲流行為中,地工止水膜和土壤介面之輸水率扮演著重要的角色。 以高嶺土作為實驗材料，用以代表黏土。實驗可變因素包括：水 頭、地工止水膜破洞面積、正向有效應力以及鋼珠的數目。我們以鋼 珠模擬現地土壤石子，以製造地工止水膜和高嶺土的不平整的接觸 面。在此研究裡，以有限元素程式（FEMWATER）配合試驗結果來 評估輸水率。網格建構時建立了一層虛擬的網格層以模擬地工止水膜 和高嶺土的空間。以試誤法讓FEMWATER所模擬出來的流量的結果 能和我們試驗時的流量的結果能夠相符合，藉以求出其輸水率。 當水頭、工止水膜破洞面積、鋼珠的數增多的時候，滲流量也增大，這是因為此時輸水率變大之故；但當正向應力增加時，滲流量將降低。而輸水率的關係顯示與滲流率關係相同。

The transmissivity of the interface plays an important role in the leakage behavior through the defects of geomembranes . Kaolinite was used to perform the experiments to represent clay. The variables controlled factors in the experiment include hydraulic head, area of defects of geomembranes, effective stress on geomembranes, and number of steel balls. Steel balls were used to simulate the gravel in the subgrade soil to produce gap between the geomembrane and Kaolinite. In this research, a computer program based on finite element method, FEMWATER , is used to compute the transmissivity. A virtual layer is assumed to simulate the space between the geomembrane and Kaolinite . Transmissivity was found by using “trial and error” method to let the discharge rate computed by FEMWATER meet the discharge rate of lab test . The results show that whenever hydraulic head, or area of defects of geomembranes, or number of steel balls increased, the leakage discharge also increased owing to the rise of transmissivity. Inaddition When effective stress on geomembranes increased, the leakage discharge decreased. Inaddition, the transmissivity displays the same relationship.