采用电阻率法的纵向弥散度室内测定研究

Laboratory evaluation of the longitudinal dispersivity with resistivity method

弥散度是表征地下水中污染物扩散的关键参数之一,对于模拟和预测污染物的扩散具有重要的意义。由于电阻率的测量具有简单快速的优势,本文采用电阻率法饱和砂体的弥散度值进行了评价。在室内进行一维水动力弥散实验,以氯化钠(NaCl)溶液作为示踪剂,采用电阻率法获得了不同位置的示踪剂穿透过程和去除过程,评价了石英砂的纵向弥散度值。结果显示:电阻率法能够得到示踪剂的扩散过程,评估的石英砂(60目)纵向弥散度值在0.166~0.225 cm范围内,平均值0.191 cm,与柱体出口测得的纵向弥散度0.233 cm相近。本研究表明电阻率法可以用于监测盐分等在多孔介质中的水动力弥散过程,并能对弥散度等关键参数进行评估。

Dispersion is one of the key parameters to characterize the diffusion of pollutants in groundwater, and it is of great significance for simulating and predicting the diffusion of pollutants. Because the advantage of measuring simple and fast, the resistivity method was used to evaluate the longitudinal dispersivity of saturated sand in this paper. A one-dimensional hydrodynamic dispersion experiment was carried out in the laboratory. Sodium chloride(NaCl) solution was used as the tracer, and the penetration process and removal process of the tracer at different positions were obtained by the resistivity method. The longitudinal dispersion of the quartz sand was evaluated. value. The results show that the resistivity method can obtain the diffusion processes of the tracer, and the longitudinal dispersivity values of the evaluated quartz sand(60 mesh) varied in the range of 0.166 to 0.225 cm, with an average value of 0.191 cm, which is consistent with the value of 0.233 cm measured at the cylinder outlet. This study shows that the resistivity method can be used to monitor the hydrodynamic dispersion processes of salt in the saturated porous media, and evaluate key parameters such as dispersivity.