土柱试验研究粘土固化注浆帷幕的阻滞性能

Retardation capability of clay-solidified grouting curtain by column test

通过室内土柱模拟试验,运用原子吸收分光光度法、紫外可见吸收光谱法等分析方法研究了粘土固化注浆结石体对无机污染物(As5+,Mn2+)和有机污染物(苯酚)的阻滞效果,用化学萃取法分析了污染物在结石体中的迁移特征,并根据试验结果通过对流 扩散方程预测了粘土固化注浆帷幕阻滞不同污染物的有效寿命。试验结果表明:结石体对无机污染物(As5+,Mn2+)的阻滞效率在试验阶段均超过了99%;对有机污染物(苯酚)的阻滞效率在试验前期可达99%,而随着时间延长,阻滞效率逐渐下降,到试验终了时不足6%;重金属离子在结石体中的迁移深度一般为0～3cm,主要聚集于距结石体顶部0.5cm之内;帷幕阻滞不同污染物的有效寿命为140～753a,表明用粘土固化注浆构筑的垂直防渗帷幕完全能够满足垃圾卫生填埋场的防渗要求。

The column test is applied for the study of typical poisonous substance (As^(5+), Mn^(2+), phenol ) reaction with the clay-solidified curtain in laboratory. With the aid of tests based on atomic absorption spectrophotometry?ultraviolet light absorption spectroscopy, the retention capability of clay-solidified grout to inorganic contaminants (As^(5+), Mn^(2+)) and organic contaminant (phenol) is investigated. The chemical extraction is applied to analyze the transport character of contaminants in grouting curtain thickness direction. Based on the test results, the effective life of clay-solidified grouting curtain for different contaminants is predicted by the advective-dispersive equation. The test results indicate that more than 99 percent inorganic contaminants (As^(5+), Mn^(2+)) are retarded by grouting curtain. For the organic contaminant (phenol), the retardation efficiency is 99 percent in the earlier stage of the test, but it is decreased with the increase of time and less than 6 percent at the end of the test. The transport depth of heavy metals is in the first 3 centimeters (especially in the first 0.5 cm) of grouting curtain columns. The effective life of grouting curtain can be 140～753 a for different contaminants. The effects show that clay-solidified grout curtain can meet the antiseeping criterion of solid waste landfills.