离心实验在污染物迁移研究中的应用

离心实验模拟以其可以获得与原型一致的应力水平并且能够大大缩短原型历时而被应用于污染物迁移实验研究。在离心相似理论及离心实验模拟的相似基础上,重点回顾了离心机在饱和带水分、非饱和带水分、保守性溶质、NAPLs、重金属、核素迁移以及污染场地修复方面的实验应用。最后讨论了离心模拟中土壤预制和加速度选择的问题,并简单介绍了离心监测方法。可以得出结论:离心机能够成功用于各类物质迁移的实验研究中,离心实验模拟能够为理论和数值等分析方法快速提供真实可靠的参数依据,但离心实验的理论基础和监测方法需要进一步完善,此外也应积极开展更接近实际情况下的离心实验模拟研究。

Application of Centrifuges in Experimental Studies of Contaminant Transport

Because the level of stress identical to that for the prototype can be attained and the experimental duration can be shortened greatly, a centrifuge is advantageous for experimental studies of flow and transport processes in the laboratory setting. This paper provides an overview of the theory of scaling laws and basic principles of centrifuge experiment and modeling, as well as some common applications of centrifuges in the study of water and moisture flow in saturated and unsaturated soils, conservative tracer transport, NAPLs contamination, heavy metal migration, radioactive nuclide movement, and contaminated land remediation. This paper also points out certain cautions that should be exercised during preparation of soil samples and selection of centrifugal accelerations. For example, the compaction of soil samples should be carefully monitored so as not to affect the reproducibility of the experiment, and the centrifuge acceleration should be maintained below the threshold where Darcy’s law becomes invalid. In addition, this paper briefly discusses the recent advances in measurement technologies relevant to centrifuge based experiments. Many successful applications have demonstrated that centrifuges are a useful tool for studying numerous flow and transport phenomena experimentally and that centrifuge modeling can rapidly and reliably provide laboratory data for developing flow and transport theories and numerical simulation methods. In the future, basic theories and monitoring methods of centrifuge experiments should be further developed and improved so that they can be applied to study more complex problems that are closer to actual situations.