Abstract:  This paper presents the geotechnical investigation results of a landfill site for the fly-ash. The site conditions such as, natural environment, hydrological conditions and physical and mechanical properties of the subsurface soils are induced in the paper. Several ground improvement methods are considered by comparing their advantages and disadvantages and the optimum ground improvement method is selected. The deep mixes by using both wet slurry and dry cement powder methods. The construction results indicate that the soil improvement method selected was successful.

Key words: Composite Ground；Soil Improvement, Fly-Ash, Soil-Cement Mix Method