As shown in Figure 11, it was estimated at 8.5 x [10.sup.-5] cm/sec and the watertightness of the core zone is judged to be fully secured so that they may serve as a seepage barrier. The relationship between seepage flow and reservoir water level for Dam B is shown in Figure 12.
Also, the watertightness of the core zone of both dams is judged to be fully secured and so they may serve as a seepage barrier.
According to the design standards of a dam in Korea [1], seepage barriers and V-notch weirs should be installed downstream from dams.
Duncan, "Deformation and cracking of seepage barriers in dams due to changes in the pore pressure regime," Journal of Geotechnical and Geoenvironmental Engineering, vol.
Normally before the construction of a seepage barrier, material that is to be used should be subjected to a variety of tests to determine its properties to assess its suitability.
Seepage barriers are often used in earth dams and levees to reduce the water flow through their foundations or embankments [1, 2].
Cement-bentonite is one of the main materials used in seepage barriers [8, 9]; in addition, to achieve the recommended hydraulic conductivity and maintain a slurry that is pumpable and economic, the cement replacement materials such as pulverised fuel ash (PFA) and ground granulated blast-furnace slag (GGBS) are commonly required [10, 11].
In the following sections, the testing procedures and theoretical models were presented; then we proposed to calculate the erosion percentage and establish the mathematical relationships between the erosion percentage and different regimes, that is, different cementitious replacement, curing period, erosion time, and sizes of initial holes to aid in assessing the internal erosion propagating from cracks in cement-bentonite seepage barriers.
Although subsurface investigation is necessary, these make ideal
seepage barriers. Where natural clay does not exist, clay can be transported to the site and compacted to a depth of several feet to form the
seepage barrier.
Impervious clay or commercially prepared mixtures of clay and bentonite provide a
seepage barrier that can be effective for creating oxidation ponds and lagoons.