重金属污染物对压实膨胀土渗透及膨胀特性影响研究

Influence of Heavy Metal Pollutants on Infiltration and Swelling Properties of Compacted Expansive clay

公路汽车排放的重金属等污染物对膨胀土路基渗透及膨胀性能的影响受到越来越多的关注。通过渗透试验和膨胀变形试验研究了不同干密度和金属污染物浓度对压实膨胀土渗透和膨胀性能的影响。试验结果表明干密度1.5 g/cm^3的压实膨胀土试样蒸馏水的渗透系数约为2×10^(-9)m/s;随着压实膨胀土试样干密度增大渗透系数显著减小。因金属污染物对膨胀土扩散双电层(DDL)的影响,压实膨胀土试样渗透系数随着金属污染物Cu^(2+)浓度的增大而增大。由于渗透固结作用,压实膨胀土试样膨胀变形随金属污染物Cu^(2+)浓度的增大而减小。

The impact of pollutants such as heavy metals from vehicle emissions on the infiltration and expansive properties of expansive clay embankment is paid more and more attention. In this paper, the effects of different dry density and metal contaminant concentration on the permeability and swelling properties of compaction expansive clays were studied by infiltration tests and expansion deformation tests. The results show that the permeability coefficient of the sample with a dry density of 1.5 g/cm3 is about 2 × 10 -9 m/s. The permeability coefficient increases significantly with the dry density of compacted expansive clay samples. Duo to the effects on DDL, the permeability coefficient of compacted expansive clay increases with the increase of Cu2＋ concentration. While the swelling strain decreases with the in- creasing of the Cu2＋ concentration by the affecting of osmotic consolidation.