Effect of Landfill Leachate on Thermo-physical Properties of Freeze-thawed Clay
To elucidate the regulatory influence of leachate on the thermal-physical properties of frozen-thawed clay,this research conducts thermal-physical property measurements on silty clay under different temperatures,types,and concentrations of pollutants,and analyzes their underlying mechanisms.The research findings indicate the following:for a single soil type,under positive temperature conditions,the thermal conductivity of soils contaminated with or-ganic pollutants(CODcr)and cadmium(Cd)increases proportionally with pollutant concentration,while for soils contaminated with ammonia nitrogen,the thermal conductivity decreases inversely with its concentration.Under neg-ative temperature conditions,the thermal conductivity of soils contaminated with CODcr and Cd decreases inversely with pollutant concentration,whereas the presence of solid solutes precipitated by ammonia nitrogen at negative tem-peratures increases the soil's thermal conductivity with increasing concentration.Regarding composite polluted soils,their thermal conductivities are inversely proportional to the concentrations of CODcr or ammonia nitrogen.Under conditions of equal CODcr concentration,the thermal conductivity of composite polluted soils decreases with increas-ing Cd concentration under positive temperatures,whereas under negative temperatures,the formation of crystalline salts due to the combination of organic pollutants and Cd results in a direct proportionality between thermal conduc-tivity and concentration.Meanwhile,the thermal conductivity of composite polluted soils containing both ammonia ni-trogen and Cd is directly proportional to the Cd concentration under positive temperatures when the ammonia nitro-gen concentration is constant,and inversely proportional under negative temperatures.Additionally,both single pollu-ted soils and composite polluted soils exhibit lower volumetric heat capacities than unpolluted soils,with a slight in-crease as pollutant concentration rises,directly proportional to temperature.In composite polluted soils,variations in CODcr and ammonia nitrogen concentrations are identified as the predominant factors affecting soil volumetric heat capacity.These research findings provide a scientific basis for quantitatively studying,evaluating,and predicting the diffusion and migration of major pollutants in leachate within frozen soil.
NETL
NSTL
万方数据
