The main aim of this research is to systematize the reinforced-earth wall system using the geosynthetic reinforcements in the weathered granite backfill soils containing relatively large amount of fines with low permeability. As a staged endeavor to accomplish this purpose, laboratory pullout tests and finite element modeling are carried out focusing on the analysis of friction characteristics associated with interaction behaviors of the geosynthetic reinforcements composed of geogrid with outstanding tensile resistance and geotextile with a sufficient drainage properties. In addition, drainage effects of the geotextile laid below the geogrid are examined based on the analysis of finite difference numerical modeling. From the present investigation, it is concluded that the geosynthetic reinforcements in the weathered granite backfills can be used to achieve combined effects of the reduction of deformations and the increase of tensile resistance, together with drainage effects.