مقاله انگلیسی رایگان در مورد نشت با عنصر غیر قابل نفوذ سدهای خاکی مرتفع – اسپرینگر 2018

Embankment dams are generally constructed of earthfll and/ or rockfll due to technical and economic reasons (Novak et al. 2007). According to the World Register of Dams by ICOLD (2017), embankment dams account for about 76% of all registered dams. High embankment dams often include two component elements, i.e., impervious water-retaining element and supporting element. As for the impervious element, compacted fne-grained silty or clayey earthflls, or artifcial materials, e.g., asphalt, concrete or geomembrane, are often employed to prevent leakage. Diferent types of coarser flls ranging up to coarse rockflls are often compacted into designated zones to provide both structural stability and good drainability. Relatively thin impervious elements are popularly employed in existing embankment dams, particularly in high embankment dams and reinforcement projects. Generally, there are two types of thin impervious elements. (1) The frst type is thin impervious element in which artifcial materials are generally used. For instance, the surface membranes or central diaphragms are thin impervious elements with thickness ranging from mm-order to m-order, for which artifcial materials such as asphalt, concrete or geomembrane are employed. The maximum thickness of concrete face of 233-m-height Shuibuya Concrete Faced Rockfll Dam (CFRD) is 1.1 m; meanwhile, the maximum thickness of concrete cutof wall of 240 m-height Changheba earth core rockfll dam is 1.4 m. Changheba earth core rockfll dam is 1.4 m. (2) The second type is thin impervious element in which nature materials are employed. The central and inclined earth cores are also classifed into thin impervious elements according to Hunter and Fell (2003), if the core width increases at less than or equal to 0.5 times the vertical distance below the crest, i.e., both upstream slope and downstream slope are less than or equal to 1:0.25 for central cores. Most constructed high earth core rockfll dams (ECRD) have thin earth core, such as 300-m-height Nurek ECRD in Tajikistan, 265-m-height Nuozhadu ECRD in China, 262-m-height Manuel Moreno Torres (Chicoasén) ECRD in Mexico and 260-m-height Tehri ECRD in India. Some embankment dams built on overburden have antiseepage systems with a combination of thin impervious element in the embankment and concrete cutof wall in overburden which may connect to grouting curtain in bed rock. Also, the combination itself forms a generalized thin impervious element.