Effect Of Temperature On Performance Of Geosynthetic Clay Liner

Owing to the good seepage control and convenient construction,Geosynthetic Clay Liner?GCL?is commonly used as the bottom liner in landfill to prevent leakage of leachate to surrounding environment,underground soil and groundwater.Because of the complex composition of the landfill,the physical and chemical reaction often produces a lot of heat,and the internal temperature in landfill can be as high as 90 degrees centigrade.The high temperature may have adverse effects on the permeable and mechanical properties of the liner system,and further threaten the safety and stability of the landfill.In this dissertation,the physical properties and hydraulic conductivity of GCL under different temperatures were studied.The influence of temperature,confining pressure,leachate on the properties of GCL was discussed.Transport law of contaminant through the liners under the temperature gradient was calculated and analyzed.?1?The temperature effect of the hydrological properties of betonites.Using the demonized water and CaCl₂ solution as experimental water,the hydrological properties of granular and powder betonites at different temperatures were studied.The relationship between adsorbed water,swelling index and temperature was obtained.?2?The temperature effect on GCL permeability.The permeability of granular and powder GCL under different hydration pressure,confining pressure,temperature and leachate conditions was studied,used with a modified GDS permeation apparatus.Combined with the research results of hydrological properties,the mechanism of GCL permeability coefficient changing with temperature was discussed.?3?The calculation of the transport of pollutants considering the thermal diffusion effect.Based on the convection-diffusion equation of traditional pollutant transport,the thermal diffusive migration caused by temperature gradient was considered,and then the analytical solution under semi infinite boundary condition was obtained.The contaminant transport rule through GCL and CCL was discussed.The difference of pollutant concentration,flux and pollutant accumulation at the bottom of the liners was compared and analyzed.