膨胀土的电导率与膨胀性的关系研究

膨胀土是一种高塑性、强亲水的黏性土。由于黏土矿物含量较高，膨胀土颗粒的交换阳离子含量也较高，总比表面积较大，在电导率测试指标上反映是膨胀土的导电性随膨胀性的增大而增强。选取强、中、弱3种不同膨胀等级的代表性试样，采用无电极电阻率测定仪和便携式电导率探头，测试了膨胀土泥浆和孔隙水溶液电导率测试，采用原子吸收光谱仪检测了膨胀土孔隙水溶液中的离子种类、含量等。研究表明，膨胀土孔隙水溶液的导电性与膨胀土泥浆的导电性均随膨胀性增大而增大，膨胀土的电导率和自由膨胀率具有良好的线性关系，工程中可以利用这一原理进行膨胀土的快速判别。

Study of relationship between electrical conductivity and swelling properties of expansive soil

Expansive soils always have high plasticity and strong hydrophilicity. Because of high clay mineral contents, high cation exchange capacity, and relatively larger specific surface area, the electrical conductivity of expansive soils increase with swelling capacity. Strong, middle and weak expansive soils are selected to study the relationships between conductivity and swelling capacity. By using non-contacting electrical resistivity device and portable conductivity probe, the electrical conductivity of both the soil slurry and the pore water are tested. And atomic absorption spectrometer is used to detect ion species and contents of pore water. Researches show that the conductivity of slurry and pore water both increased with swelling capacity, and the increasing trend show a good linear relationship. Thus, conductivity can be a good method for rapid identification of expansive soils.