Coupled Solute Migration Through Clay Barrier Materials

通过粘土屏障材料的耦合溶质迁移

• 批准号: 9616854
• 负责人: Charles Shackelford
• 金额: $ 13.67万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-09-15 至 2000-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9616854&HistoricalAwards=false
• 关键词: Coupled; Solute; Migration; Through; Clay

9616854 The traditional advection-dispersion theory for miscible contaminant (solute) migration through soil in reality represents a limiting case of the more general coupled-flow theory in which the coupling terms (e.g. water flow due to chemico-osmosis) are assumed to be zero. While this assumption is generally acceptable in the case of miscible contaminant migration through relatively high permeability materials, the accuracy of this assumption in terms of the relatively low-permeability, fine-grained materials typical of pollutant barriers has not been formally evaluated. The goal of this study is to evaluate the significance of chemico-osmosis and electro-osmosis on the migration of miscible contaminants through engineered clay barriers used for waste containment and in situ remediation. The following objectives will be addressed: * coupled flow parameters (e.g. hydraulic, chemico- osmotic, and electro-osmotic conductivity; electrical conductance; and osmotic efficiency coefficient) for clay soils will be measured under several different test conditions (stress, compaction, solute concentration and type); * parameters expected to dominate solute transport under low-flow conditions will be measured independently for the same soils, solutes, and test conditions; * measured migration rates of the solutes through laboratory soil columns will be compared with predicted rates using analytical models based on both the coupled flow and the advective-diffusive modeling approaches; and * a finite difference model will be developed and used to evaluate the potential effect of volume change on solute mass flux for both coupled flow and the advective-diffusive modeling approaches. ***

9616854 传统的对流-弥散理论在土壤中的可混溶污染物（溶质）迁移实际上代表了更一般的耦合流理论的一种限制情况，其中耦合项（例如，由于化学渗透的水流）被假定为零。 虽然这种假设在混溶污染物通过渗透性相对较高的材料迁移的情况下通常是可以接受的，但这种假设在渗透性相对较低的细颗粒污染物屏障材料方面的准确性尚未得到正式评估。 本研究的目的是评估化学渗透和电渗透对可混溶污染物通过工程粘土屏障迁移的意义，该工程粘土屏障用于废物遏制和原位修复。 将实现以下目标： * 将在几种不同的试验条件（应力、压实、溶质浓度和类型）下测量粘土的耦合流动参数（例如水力、化学渗透和电渗传导率;电导率;和渗透效率系数）; * 对于相同的土壤、溶质和试验条件，将独立测量预期在低流量条件下主导溶质运移的参数; * 将通过实验室土柱测量的溶质迁移速率与使用基于耦合流和对流扩散模拟方法的分析模型预测的速率进行比较;以及 * 将开发一个有限差分模型，并用于评估体积变化对耦合流动和对流-扩散模拟方法的溶质质量通量的潜在影响。 ***