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首页> 外文期刊>Journal of Contaminant Hydrology >Evidence of preferential path formation and path memory effect during successive infiltration and drainage cycles in uniform sand columns
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Evidence of preferential path formation and path memory effect during successive infiltration and drainage cycles in uniform sand columns

机译：均匀砂柱连续渗水和排水过程中优先路径形成和路径记忆效应的证据

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摘要

The formation of preferential flow paths in the partially saturated zone, and in naturally structured media, is well known. This study examines non-uniform flow in uniform sand columns under different pressure and infiltration/drainage conditions. Experiments were carried out in a vacuum box, with applied suction set to three different heads, and with infiltration fixed at two different flow rates. Tailing observed in some conservative tracer breakthrough curves suggests the formation of immobile resident water pockets which slowly exchange mass with the flowing water fraction. The applied suction controlled the degree of water immobilization whereas flow rate had minimal effect on the dynamic behavior. Trapping and exchange of water occurred repeatedly during successive infiltration and drainage cycles, implying a (hysteretic) memory effect of the previously formed preferential flow paths. Flow and solute transport modeling suggests that these dynamics can be described by a mobile-immobile model that corroborates measurements suggesting preferential flow path formation. These findings have implications for the natural attenuation of contaminants in the partially saturated zone, but also for the persistence of a contamination source exposed to repeated conditions of infiltration and drainage.
机译：在部分饱和区和自然结构化介质中形成优先流动路径是众所周知的。这项研究研究了在不同压力和渗透/排水条件下均匀砂柱中的非均匀流动。实验是在真空箱中进行的，将吸力设置为三个不同的头，渗透率固定为两个不同的流量。在一些保守的示踪剂穿透曲线中观察到的尾矿表明形成了不动的常驻水囊，该静水囊与流动的水馏分缓慢交换质量。施加的吸力控制了水的固定程度，而流速对动态行为的影响则最小。在连续的渗透和排水循环中反复发生水的捕集和交换，这意味着先前形成的优先流动路径的（滞后）记忆效应。流动和溶质运移建模表明，这些动力学可以通过移动固定模型来描述，该模型证实了表明优先流动路径形成的测量结果。这些发现不仅对部分饱和区中的污染物自然衰减有影响，而且对暴露于反复渗透和排水条件下的污染源的持久性也有影响。

著录项

  • 来源
    《Journal of Contaminant Hydrology》 |2014年第9期|1-10|共10页
  • 作者

    Leon Kapetas; Ishai Dror; Brian Berkowitz;

  • 作者单位

    Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel,Department of Geoscience & Engineering, Delft University of Technology, 2628 CN Delft, The Netherlands;

    Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel;

    Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    Unsaturated zone; Old-new water; Contaminant transport;

    机译：不饱和区;新旧水;污染物运输;

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