earthfilled

Earthfilled, also written as earth-fill or earth-filled, is a term used in civil engineering to describe materials or structures that are composed primarily of compacted earth. It is most commonly associated with embankments and barriers such as earthfill dams, levees, and fills used to raise roadways or shoreline contours. In dam design, an earthfilled dam typically features a relatively impermeable core—often clay—surrounded by more permeable outer shells of sand or gravel, with drainage provisions to manage seepage.

Materials used for earthfilled constructions are selected for local availability, density, and permeability. Common compositions include clay-rich soils for low permeability, reinforced by granular layers to provide stability and drainage. The construction process generally involves placing the material in successive lifts (layers) and compacting each lift to achieve the desired dry density. Moisture content is controlled to optimize compaction. In some cases, hydraulic fill methods may be used, where a slurry of soil and water is deposited into place and later compacted as it consolidates.

Earthfilled structures are favored for their cost-effectiveness and ability to utilize locally sourced soils. They are widely used in dams, reservoirs, road embankments, and land reclamation. However, they require careful design and maintenance to mitigate issues such as seepage, internal erosion (piping), slope instability, and erosion of exposed surfaces. Proper drainage, filters, and protective facing are essential components of a robust earthfilled system.

Terminology varies by region; terms like earthfill, soil-fill, and fill material are often used interchangeably in practice. See also: earth dam, embankment dam, and fill (civil engineering).