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Earthworks
Published in Jonathan Knappett, R. F. Craig, Craig’s Soil Mechanics, 2019
Jonathan Knappett, R. F. Craig
An embankment dam would normally be used where the foundation and abutment conditions are unsuitable for a concrete dam and where suitable materials for the embankment are present at or close to the site. They are also commonly used at a smaller scale in the construction of flood protection berms. Adequate performance under groundwater seepage is an additional design requirement that must be added to the list above for embankments.
Safeguard embankment dam safety
Published in Jean-Pierre Tournier, Tony Bennett, Johanne Bibeau, Sustainable and Safe Dams Around the World, 2019
Embankment dams are a versatile type of dam that can be founded on a variety of soil and rock sites. In general, an embankment dam is an earth- and/or rockfill retaining structure, including concrete-faced rockfill structure, which can store water or mixture of fluid/solid. Embankment dams offer little erosion resistance, when the retained water or fluid/solid level rises above the dam crest. Thus, once overtopped, an embankment dam is often doomed to be down cut by continual erosion of released water or mixture of fluid/solid, resulting in dam breach and downstream flooding in rapid succession. The release of stored materials, if contaminated, could subject the downstream area to environmental pollution besides flood inundation. This paper starts with a brief description of an embankment dam, its main elements, affiliated facilities and common characteristics. It then provides an overview of natural and human hazards and factors that might influence the integrity and safety of the dam structure.
Stability of slopes
Published in R.F. Craig, Craig’s Soil Mechanics, 2004
Failure of an embankment dam could result from the following causes: (1) instability of either the upstream or downstream slope, (2) internal erosion and (3) erosion of the crest and downstream slope by overtopping. (The third cause arises basically from errors in the hydrological predictions.)
A method to assess the suffusion susceptibility of low permeability core soils in compacted dams based on construction data
Published in European Journal of Environmental and Civil Engineering, 2019
Lingran Zhang, Rachel Gelet, Didier Marot, Marc Smith, Jean-Marie Konrad
Internal erosion is one of the main causes of embankment dam failures (Foster, Fell, & Spannagle, 2000). Based on the physics of the process and on its location within a structure, four types of internal erosion can be identified: concentrated leak erosion, backward erosion, contact erosion and suffusion (Fry, 2012). Suffusion is a complex process that under seepage flow, the fine solid particles can be detached, transported, and for some of them blocked. The finer fraction eroded and leaving the coarse matrix of the soil will further modify the hydraulic conductivity and mechanical parameters of the soil. On-going suffusion may result in an increase of permeability, greater seepage velocities and potentially higher hydraulic gradients, possibly accelerating the rate of suffusion (Icold, 2013). The development of suffusion gives rise to a wide range of dam incidents including piping and sinkholes.