Selecting Optimum Cutoff Wall Position for Rehabilitation of an Inclined Core Earthfill Dam
Over the last few decades, a particular number of existing dams in Iran have required rehabilitation to improve the water sealing system performance. This paper aims to thoroughly investigate the effect of the cutoff wall position on the seepage behavior of an existing earthfill dam with an inclined core. Several conditions are considered for the permeability and depth of a dam foundation. Then, for each condition, the remedial cutoff wall is imposed in dam at various locations and the seepage pattern and magnitude through the foundation is analyzed via finite element GeoStudio SEEP/W software.
The analyses results show that if the cutoff wall is not connected to a lower impervious layer of foundation, the effects of the cutoff wall position variations on the seepage value are insignificant. However, if the cutoff wall is constructed at the dam heel, minimum seepage occurs. When the cutoff wall covers the whole of pervious foundation, the seepage through foundation is fully corresponded to the cutoff wall position. Minimum seepage is observed in cases where the cutoff wall is constructed from the dam crest. Besides, in foundation with higher permeability, the effect of the cutoff wall position on the seepage is more significant.
KeywordsRemedial cutoff wall Inclined clay core Earthfill dam Seepage analysis Rehabilitation
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