Abstract: In order to improve the impermeability of natural soil in refuse landfill,and not to cause pollution to underground water,some materials with a certain adsorption,such as bentonite,zeolite,and ganister sand,are selected to add into the soil.Bentonite,zeolite,and ganister sand were added into the natural soil of refuse landfill in different proportions respectively and variable head permeability tests were carried out after compacting.Following conclusions were obtained:The optimum mix ratio of bentonite-modified soil sample is 8% (mass fraction) and its osmotic coefficient is 5.85×10^-8 cm/s at standard temperature;the optimum mix ratio of zeolite-modified soil sample is 2% (mass fraction) and its osmotic coefficient is 8.97×10^-9 cm/s at standard temperature;and the optimum mix ratio of ganister sand-modified soil sample is 2% (mass fraction) and its osmotic coefficient is 1.52×10^-7cm/s at standard temperature.According to the stipulation of related national standard,compacted ganister sand-modified soil sample can be used as a protective layer of refuse landfill,and compacted bentonite-modified and zeolite-modified soil samples can be used as impermeable lining of refuse landfill.

Key words: bentonite, zeolite, ganister sand, refuse landfill, osmotic coefficient