垃圾填埋场天然土壤衬垫改性的对比研究

Comparative study on modification of natural soil liner in refuse landfill

为了提高垃圾填埋场天然土壤的抗渗性,同时不对地下水造成污染,选择往土壤中添加具有一定吸附性的膨润土、沸石和硅粉。在垃圾填埋场天然土壤中分别添加不同比例的膨润土、沸石和硅粉,击实后进行变水头渗透试验,得出如下结论:膨润土改性土样的最佳配比为8%(质量分数),其在标准温度下的渗透系数为5.85×10-8cm/s;沸石改性土样的最佳配比为2%(质量分数),其在标准温度下的渗透系数为8.97×10-9cm/s;硅粉改性土样的最佳配比为2%(质量分数),其在标准温度下的渗透系数为1.52×10-7cm/s。根据国家规定的标准,压实的硅粉改性土样可以作为垃圾填埋场的保护层,压实的膨润土和沸石改性土样可以作为垃圾填埋场的防渗衬层。

In order to improve the impermeability of natural soil in refuse landfill, and not to cause pollution to under- ground 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 l and its osmotic coeffi- cient 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.