کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4546520 1627043 2014 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Evidence of preferential path formation and path memory effect during successive infiltration and drainage cycles in uniform sand columns
ترجمه فارسی عنوان
شواهد شکل گیری مسیر ترجیحی و اثر حافظه مسیر در طی نفوذ متوالی و دوره های زهکشی در ستون های شن و ماسه یکنواخت
کلمات کلیدی
منطقه غیر اشباع، آب های قدیمی حمل و نقل آلودگی
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
چکیده انگلیسی


• We examine “old” and “new” water in sand columns for cycles of infiltration–drainage.
• Memory effects of previously formed preferential flow paths are implied during these cycles.
• Mobile–immobile model quantification corroborates preferential flow path formation.

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.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Contaminant Hydrology - Volume 165, September 2014, Pages 1–10
نویسندگان
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