应用土柱试验求解地下含水介质弥散系数

Application of Calculating the Diffusion Coefficient of Under ground Water-bearing Soil Media Through Soil Column Tests

污染物质在地下含水介质中的运移,除受渗透系数等水文地质条件的制约外,还受到含水介质弥散系数的控制。污染物的扩散,首先是从包气带开始进行的,浑河冲洪积扇地包气带主要岩性是亚粘土及亚砂土,因此,计算出浑河冲洪积扇包气带的弥散系数,对于认识污染物的运移能力是一项必要的工作。本文利用室内动态土柱装置,模拟包气带岩性环境,以0.05 mol/L的NaCl溶液作为示踪剂,经长时间监测,运用弥散系数计算公式进行求参。计算结果是包气带以亚粘土为主要岩性的弥散系数为0.005 71 m2/d,亚砂土的弥散系数为0.012 47 m2/d。

The migration of pollutants in the ground water-bearing media is not only controlled by the permeability coefficient of hydro-geological conditions but also by the diffusion coefficient of water medium.The spread of pollutants starts from the vadose zone,and the lithology in the vadose zone of the Hun River Alluvial Fan lithology is mainly sub-clay and sub-sandsoil,therefore,calculating the vadose zone diffusion coefficient of the Hun River alluvial fan to understand the migration ability of contaminants is a necessary work.First of all,simulating the lithofacies environment of the vadose zone through the indoor dynamic soil column unit.Second,confecting 0.05 mol/L NaCl solution as tracer to monitor the changes of the concentration for a long time.The last,using the diffusion coefficient formula to calculate the parameters.The conclusion of diffusion coefficients are 0.005 71 m2/d in the sub-clay and 0.012 47 m2/d in the sub-sandsoil.