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垃圾填埋场底部铺设含黏土或膨润土掺砂混合土的防渗系统,防止渗滤液流入地下污染周边环境。采用模型试验研究Ca~(2+)离子浓度和基础局部沉降对膨润土掺砂混合土渗透特性的影响。试验结果表明Ca~(2+)浓度对膨润土掺砂混合土的渗透性能有较大影响,渗透液中Ca~(2+)浓度超过一定值后混合土渗漏;Ca~(2+)离子浓度与发生渗透时间之间有很大关系,浓度越高发生渗透的时间越短;同样沉降量条件下,含Ca~(2+)离子溶液渗透的混合土均发生渗漏,而用蒸馏水作渗透液的没有出现渗漏;钠基膨润土遇Ca~(2+)离子溶液后,当Ca~(2+)离子浓度大于两倍Na+就会发生离子交换,钠基膨润土转化为钙基膨润土,混合土的防渗性能下降。因此开展Ca~(2+)离子浓度对膨润土掺砂混合土渗透特性的研究具有较好的理论和实际意义。
At the bottom of the landfill, an anti-seepage system shall be laid with clay or bentonite-mixed soil to prevent the leachate from flowing into the ground to pollute the surrounding environment. The effects of Ca2 + ion concentration and basic subsidence on infiltration characteristics of bentonite mixed soil were studied by using model tests. The results showed that Ca2 + concentration had a significant effect on the permeability of bentonite mixed soil. When the concentration of Ca2 + in the permeate exceeded a certain value, the mixed soil leached. Ca2 + There is a great relationship between concentration and infiltration time. The higher the concentration is, the shorter the infiltration time is. Under the same sedimentation condition, the mixed soil with Ca2 + Leakage of leachate did not occur. When Na-bentonite was exposed to Ca 2+ ion solution, ion exchange occurred when Ca 2+ ion concentration was more than twice Na +, sodium bentonite was converted to Ca-bentonite, Impermeability of mixed soil decreases. Therefore, it is of great theoretical and practical significance to carry out the research on the infiltration characteristics of Ca ~ (2+) ion mixed with bentonite sand mixed soil.