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黏土与一定量膨润土混合,构成阻滞垃圾填埋场污染物迁移的黏土–膨润土屏障。试验研究了不同膨润土含量的黏土–膨润土混合物中Cl迁移扩散规律,使用经验公式和解析方法对试验结果进行拟合,获得Cl在土–膨润土混合物中的有效扩散系数,通过数值分析探讨了天然堆场或简易填埋场使用土–膨润土屏障进行污染防治的可行性。试验结果表明,加入膨润土后黏土渗透系数和有效扩散系数显著降低,在试验涉及的膨润土含量范围内,渗透系数和扩散系数的对数值与膨润土含量之间呈线性关系;所使用的解析方法能综合考虑对流和扩散作用,得出的有效扩散系数比通常采用的经验公式更为准确;取场底渗滤液水头为30 cm和3 m进行对流–扩散分析,表明天然垃圾堆场或简易填埋场较易对周边造成污染,黏土–膨润土屏障可有效避免或降低污染。
Clay is mixed with a certain amount of bentonite to form a clay-bentonite barrier that retards the migration of landfill contaminants. The migration and diffusion of Cl in clay-bentonite mixtures with different bentonite contents were studied. The empirical formula and analytical method were used to fit the test results. The effective diffusion coefficient of Cl in the soil-bentonite mixture was obtained. The natural heap Feasibility of using soil-bentonite barrier for pollution control in field or simple landfill. The experimental results show that the clay permeability coefficient and effective diffusion coefficient decrease significantly after the addition of bentonite. The logarithm of the permeability coefficient and diffusion coefficient has a linear relationship with the bentonite content within the range of the bentonite content involved. The analytical methods used can synthesize Considering the effects of convection and diffusion, the effective diffusion coefficient obtained is more accurate than the commonly used empirical formula. The convection-diffusion analysis of 30 cm and 3 m heads of the leachate at the bottom of the field shows that natural landfill or simple landfill Easier to the surrounding pollution, clay - bentonite barrier can effectively prevent or reduce pollution.