Yang Lu

Constructing the impervious system of an Earth Core Rockfill Dam (ECRD) usually needs a large volume of clay that may exhaust a huge area of farmland. One way to reduce the volume of clay to be filled is to use natural clay-gravel mixtures (CGM) or to add an appropriate percent of gravel materials into the clay and use the artificial clay-gravel mixtures as the impervious core materials. Using clay-gravel mixtures can also effectively increase the modulus of the core and reduce the differential settlement between the core and its adjacent rockfill shoulders, and thus alleviate the risk of occurrence of potential cracks within the core wall. The impermeability behavior of the compacted clay-gravel mixtures, however, has to be careful investigated and verified. In this chapter, four cases in using clay-gravel mixtures in constructing high ECRDs in China are reviewed, with attention focused on the engineering properties of clay-gravel mixtures and the construction and field quality control aspects of ECRDs using clay-gravel mixtures.