Seepage Barrier

a structure designed to prevent water seepage, built into a foundation and in areas adjoining head-works; it is constructed by injecting various grouts into the soil through boreholes.

The main purpose of a seepage barrier is to reduce the rate of seepage and the loss of water from a reservoir and to reduce the pore pressure on the structure. Depending on the type of soil and its geological properties, seepage barriers are installed by cement grouting, hot and cold asphalt grouting, or by clay grouting (seeSOIL STABILIZATION). A barrier may be grouted in a vertical or inclined configuration under or near the headworks, or may be grouted in the shore of a reservoir. The barrier’s depth is determined by trial injecting water or air under pressure into a hole. The depth in some instances may be considerable, for example, 210 m for the Mauvoisin dam in Switzerland.

V. N. POSPELOV

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References in periodicals archive ?

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.

Seepage Behavior of Earth Dams Considering Rainfall Effects

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.

Investigation of Erosion of Cement-Bentonite via Piping

"Martin County attempted to use a blanket of spoil pushed over from above to form a seepage barrier," Gardner said.

Design Alternatives

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.

Surface reservoirs

Impervious clay or commercially prepared mixtures of clay and bentonite provide a seepage barrier that can be effective for creating oxidation ponds and lagoons.

Oxidation ponds

Certain levee sites will be strengthen by installing water seepage barriers, widen and raise levee heights and improve erosion protection along the river.