Concerns Rise Over Vulnerabilities of Concrete-Faced Rockfill Dams Amidst Shift Back to Earth Core Rockfill Dams.

Concrete-faced rockfill dams (CFRD) have been the preferred dam type for high embankment dams for almost fifty years. They are claimed to be the safest dam type by their proponents and have been replaced by earth core rockfill dam (ECRD), the dam type which was replaced by CFRDs. These dams are also built in seismically active regions and are often used as storage devices. The author discusses the vulnerabilities of CFRDs and compares them to those replaced by ECRDs. Overtopping depths of up to about 2m may be accepted for concrete dams, but this may be checked due to the sliding stability of overtopped dams. Dam protection against internal erosion can be provided by an adequate freeboard, by widening and strengthening the crest, by wave walls, etc. However, problems caused by the different deformational behaviour of the concrete face and the rockfill could be overcome by using rockfill with a high modulus of elasticity and by providing adequate vertical and horizontal joints in the face slab.