Embankment dam
A homogeneous rolled-earth dam is entirely constructed of one type of material but may contain a drain layer to collect seep water.
An outdated method of zoned earth dam construction used a hydraulic fill to produce a watertight core.
Its height of 485 ft (148 m) above the river bed and 95 sq mi (250 km2) reservoir make it the largest earth-filled dam in the world.
Because earthen dams can be constructed from local materials, they can be cost-effective in regions where the cost of producing or bringing in concrete would be prohibitive.
The impervious zone may be on the upstream face and made of masonry, concrete, plastic membrane, steel sheet piles, timber or other material.
To prevent internal erosion of clay into the rock fill due to seepage forces, the core is separated using a filter.
Liquefaction potential can be reduced by keeping susceptible material from being saturated, and by providing adequate compaction during construction.
The type of asphalt used is a viscoelastic-plastic material that can adjust to the movements and deformations imposed on the embankment as a whole, and to settlement of the foundation.
This design provides the concrete slab as an impervious wall to prevent leakage and also a structure without concern for uplift pressure.
In addition, the CFRD design is flexible for topography, faster to construct and less costly than earth-fill dams.
The CFRD concept originated during the California Gold Rush in the 1860s when miners constructed rock-fill timber-face dams for sluice operations.
Even a small sustained overtopping flow can remove thousands of tons of overburden soil from the mass of the dam within hours.
The embankment, having almost no elastic strength, would begin to break into separate pieces, allowing the impounded reservoir water to flow between them, eroding and removing even more material as it passes through.
[12] These techniques include concrete overtopping protection systems, timber cribs, sheet-piles, riprap and gabions, Reinforced Earth, minimum energy loss weirs, embankment overflow stepped spillways, and precast concrete block protection systems.
