Earth / Rockfill Dams

Embankment Dams

Embankment dams are mainly made from natural materials. They are suited to sites with wide valleys and shallow slopes, creating relatively wide and shallow reservoirs. They can be constructed on relatively weaker and not homogenous soils. The construction of a spillway that will release water from the reservoir when the water level rises too high is necessary as embankment dams are vulnerable to erosion caused by overflow of water. The two main types of these dams are earthfill embankment dams and rockfill embankment dams. The materials are usually excavated or quarried from the surrounding area. This kind of dam, shown in cross-section, appears like a bank or hill.

Earthfill Dams

Earthfill dams are made up mostly of compacted earth. Most embankment dams have a zone in the middle, called the core, made of low permeability  material, a permeable part growing gradually outward called a filter on the two sides covering the core, and the shell on the upstream and downstream heels. The core is usually made of clayey soils to stop water passing through the dam.

Rockfill Dams

Rockfill dams are mainly made from dumped and compacted rock fill. Rockfill dams are permeable. They have an impermeable core or an impermeable layer on the upstream face of the dam to prevent seepage through the porous core. The impermeable parts are usually made of reinforced concrete, asphaltic concrete or clay.

Top 10 papers on Embankment Dams

Recommended list of publications on embankment Dams by David Rees Gillette, P.E., PhD, Bureau of Reclamation, Denver CO.

List originally compiled: June 2005  Latest update: May 2011

Comments of the author of the list are presented in italics.

• Casagrande, A. (1961), “Control of Seepage through Foundations and Abutment of Dam,” First Rankine Lecture, Geotechnique vol.11, no. 3, pp 159-182. Is there anything more important than foundation preparation?

• Houlsby, A.C. (1977), "Engineering of Grout Curtains to Standards," Journal of the Geotechnical Division, Proceedings of the American Society of Civil Engineers, Vol. 103, No. GT9, pp. 953-970. One of relatively few good references I've seen on the practice of foundation grouting.

• Milligan, Victor, "Some Uncertainties in Dam Engineering," 38th Karl Terzaghi Lecture, Journal of Geotechnical and Geoenvironmental Engineering, vol. 129, no. 9, pp.785-797. Excellent practical lessons from case histories.

• Peck, R.B. (1988), "The Place of Stability Analysis in Evaluating the Safety of Existing Embankment Dams," Civil Engineering Practice, Fall 1988, pp. 67-80. Everybody does stability analysis. But what does it mean?

• Seed, H.B., F.I. Makdisi, and P. de Alba (1978), "Performance of Earth Dams During Earthquakes," Journal of the Geotechnical Division, Proceedings of the American Society of Civil Engineers, Vol. 104, No. GT7, pp. 967-994. Review and analysis of case histories.

• Sherard, J.L. (1987), "Lessons from the Teton Dam Failure," Engineering Geology, vol. 24, pp. 239-256 and discussions that follow. Probably the single most important case history of a dam failure for us to learn about foundation treatment, site selection, and dam-safety "culture."

• Sherard, J.L. and J.B. Cooke (1987), "Concrete Face Rockfill Dam: I. Assessment," ASCE Journal of Geotechnical Engineering, Vol. 113, No.10, pp. 1096-1112, and Cooke, J.B. and J.L. Sherard (1987), "Concrete-Face Rockfill Dam: II. Design," ASCE Journal of Geotechnical Engineering, Vol. 113, No.10, pp. 1113-1132.

• Sherard, J.L. and L.P. Dunnigan, (1989), “Critical Filters for Impervious Soils," ASCE Journal of Geotechnical Engineering, Vol. 115, No. 7, pp. 927-947. The basis for most modern filter criteria.

• Terzaghi, Charles, (1929), "The Effects of Minor Geologic Details on the Safety of Dams," Transactions, American Institute of Mining and Metallurgical Engineers, 215, pp. 31-44. Also known as Terzaghi, Karl.

• Terzaghi, K. and Y. LaCroix (1964), "Mission Dam: An earth and rockfill dam on a highly compressible foundation," Geotechnique, vol. 14, no. 1, pp. 14-50. Fascinating case history of a dam constructed under very difficult conditions on a very difficult foundation.

Some others of note:

• Duncan, J.M., S. Wright, and K.S. Wong (1988), "Slope Stability During Rapid Drawdown", H.B. Seed Memorial Volume, pp. 253‑272.

• Lowe, J. III (1982), "Contributions of the Tarbela Dam Project to Hydro-Project Design," Second Annual USCOLD Lecture, Atlanta, Georgia.

• Marcuson, W.F. III, P.F. Hadala, and R.H. Ledbetter (1996), "Seismic Rehabilitation of Earth Dams,", ASCE Journal of Geotechnical Engineering, Vol. 122, No. 1, pp. 7-20.

• Middlebrooks, T.A. (1952), "Progress in Earth-Dam Design and Construction in the United States," Civil Engineering, September 1952.