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

对受污染土壤随时间结构变化的非侵入性调查

• 批准号: 9813226
• 负责人: Fred Boadu
• 金额: $ 21.09万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-01-01 至 2004-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9813226&HistoricalAwards=false
• 关键词: Non; Invasive; Investigation; Structural; Changes

***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.***

* 9813226 Boadu本研究探讨了非侵入性评估的可能性，不同成分的污染土壤结构变化的演变。 该假说认为，结构变化是由于颗粒间间距的大小变化，而成分变化是由于间距中的离子或溶液置换。 这些变化导致导水率和孔隙度的改变。 了解污染土壤中的这些变化是很重要的，如果要采取适当的措施来实施污染物的储存或修复，就需要进行非侵入性的评估。这项研究将包括实验室测量污染土壤的光谱电响应，并结合土壤-污染物系统的理论和等效电路模型。 电性能的研究将提供有关孔几何形状和孔表面积的信息，因为孔空间中自由电荷载流子的传输和孔-颗粒界面处的极化都有助于总电导率。 实验研究涉及不同比例的粘土、淤泥和沙子的土壤污染物混合物，混合有孔隙流体，包括有机和无机化学品（酸和碱）和石油产品（例如，煤油）。 允许土壤混合物随时间相互作用，并测量频率相关的电响应。 将采用一种使用非线性优化方案的反演方法，模拟退火，来检索土壤系统随时间变化的电参数和物理化学参数。*