Soil Mechanics and Foundation Engineering Twelfth National Congress, Konya, Turkey, 16 - 18 October 2008, pp.571-582
In areas where river sediments are thick, construction of earth dams by excavating these
sediments and replacing with compacted fill may cause substantial cost increases. River
sediments consists of either granular (sand, gravel) or fine-grained (silt, clay) materials.
Granular sediments can be improved with relative ease against instability and
compressibility; however, because such deposits are highly permeable, additional measures
are required to prevent seepage loss through the dam foundation. Fine-grained deposits, if
they do not contain extensive sand or gravel lenses, offer less problems relative to seepage
loss and may not require seepage control measures. However, such materials typically
have low strength and high compressibility and present stability and settlement concerns.
The objective of this article is to summarize behavior of earth dams constructed directly
over fine-grained river sediments and to present examples of such dam projects. Available
methods for improvement of highly compressible, low strength deposits are limited.
Because it is generally more economical, the design principles of staged construction and
the relevant methods of analysis are presented herein. Alibey Dam for slow staged
construction and Hamzadere Dam (not yet constructed) for accelerated staged construction
are presented as examples. The results of analyses and observations indicate that earth
dams can be constructed directly on soft fine grained river sediments with staged fill
placement economically and with acceptable time durations