A Non-Invasive Investigation of the Structural Changes in Contaminated Soils Over Time

*9813226 Boadu这项研究探索了非侵入性评估不同成分污染土壤结构变化演变的可能性。假设结构变化是粒子间距大小变化的结果，而组成变化是离子或溶液置换间距的结果。这些变化导致了导水率和孔隙度的变化。如果要采取适当的措施来实施污染物的储存或修复，关于污染土壤中这种变化的知识是重要的，需要进行非侵入性评估。调查将涉及结合土壤-污染物系统的理论和等效电路模型的受污染土壤的光谱电响应的实验室测量。电学性质的研究将提供关于孔几何和孔表面积的信息，因为自由载流子在孔道中的传输和孔-颗粒界面的极化都对总电导率有贡献。实验研究涉及不同比例的粘土、粉砂和沙子的土壤污染物混合物，与包括有机和无机化学品(酸和碱)以及石油产品(如煤油)的孔隙流体混合。土壤混合物将被允许长期相互作用，并将测量与频率相关的电响应。采用一种非线性优化方案--模拟退火法--的反演方法将被用来随时间的推移来反演土壤系统的电学和物理化学参数。

***9813226BoaduThis research explores the possibility of assessing non-invasively, theevolution of the structural changes in contaminated soils of differentcomposition. The hypothesis is that structural changes result from changesin the size of inter-particle spacing, and compositional changes resultfrom ionic or solution replacement in the spacing. These changes result inmodification of hydraulic conductivity and porosity. Knowledge about suchchanges in contaminated soils is important and needs to be assessednon-invasively if proper measures are to be taken to implement storage orremediation of contaminants.The investigation will involve laboratory measurements of the spectralelectrical response of contaminated soils integrated with theoretical andequivalent circuit models of the soil-contaminant system. Studies of theelectrical properties will provide information on the pore geometry andpore surface area as both transport of free charge carriers in the porespace and polarization at the pore-grain interfaces contribute to the totalconductivity. The experimental study involves soil-contaminant mixtures ofvarying ratios of clay, silt and sand, mixed with pore fluids that willinclude organic and inorganic chemicals (acids and bases) and petroleumproducts (e.g., kerosene). Soil mixtures will be allowed to interact overtime and the frequency-dependent electrical response will be measured. Aninversion method using a nonlinear optimization scheme, simulatedannealing, will be employed to retrieve the electrical and physico-chemicalparameters of the soil system over time.***