CFRD (Concrete Faced Rockfill Dam) has been world-widely constructed due to a lot of
advantages compared with rockfill dam and recently, sand/gravel materials, instead of crushed rock materials,are also utilized as a main rockfill material to overcome geological and environmental problems. In this paper,the process of water infiltration into the originally unsaturated sand/gravel-fill dam is studied using two-dimensional saturated-unsaturated seepage theory. According to the results of seepage analysis, if the effective drainage zone is installed in the dam, the reservoir water infiltrate into the dam along a downward flow path towards the lower drainage area. The main body constructed with sand/gravel materials, therefore,remains unsaturated.
