Abstract
Most of old fill type dams were accumulated with a muddy soil in reservoirs that caused the pollution and the loss of reservoir capacity. This muddy soil is generally high-water-content and very soft clayey soil. We have developed a new type method to repair the old embankment by the cement-mixed muddy soil in order to make efficient use of such a problematic soil as embankment soil. In this paper, we investigate the grading and the plasticity characteristics of the muddy soil accumulated in areservoirs to apply this reparing method adequately to improve the old fill type dam embankments. From our results, we concluded that the strength management of cement-mixed muddy soil required to concider the effects of the grading and the water content of the muddy soil in case of the fill type dam reservoirs because there is very much change of the grading.
