Temperature Effects on the Permeability of Sand-Palygorskite Cutoff Walls in Landfill
摘要
Due to low permeability and good antifouling properties of palygorskite, palygorskite has been suggested as a liner material in vertical cutoff wall applications. Meanwhile, the biochemical degradation of waste in landfills generates a large amount of heat, and the temperature can reach 60 °C. There is a lack of corresponding studies on the effect of temperature on the permeability of sand-palygorskite vertical cutoff walls in municipal solid waste landfill. To this end, this paper carries out experimental research on sand-palygorskite permeability tests, consolidation tests and liquid limit tests at different temperatures. The results show that the hydraulic conductivity of sand-palygorskite samples gradually increases with increasing temperature, and the response of the hydraulic conductivity of sand-palygorskite to temperature was further analysed for different doses of palygorskite and consolidation pressures. It was found that the response of the hydraulic conductivity kf to temperature T of the sand-palygorskite increased with increasing palygorskite dosage, while the response of the hydraulic conductivity kf to temperature T of the sand-palygorskite decreased with increasing consolidation pressure. According to the calculation method proposed by previous researchers, the consolidation theoretical hydraulic conductivity of soil was calculated. The Kozeny—Carman equation was further modified using the void ratio and liquid limit, and a prediction equation was obtained for the hydraulic conductivity of sand-palygorskite at different temperatures. This study can provide an important theoretical basis and data support for the development of new high-performance long-life vertical cutoff walls in a municipal solid waste landfill.