חיפוש מתקדם
Water Resources Research
Assouline, S., Laboratory of Soil and Environmental Physics, School of Architectural, Civil and Environmental Engineering, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland, Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel, Institute of Soil, Water and Environmental Sciences, ARO, Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel
Or, D., Laboratory of Soil and Environmental Physics, School of Architectural, Civil and Environmental Engineering, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland, Laboratory of Soil and Environmental Physics, School of Architectural, Civil and Environmental Engineering, EPFL, CH-1015 Lausanne, Switzerland
Variations in the degree of anisotropy in soil hydraulic conductivity with changes in water saturation (Se) may adversely impact predictability of flow and transport processes. The conceptual "layered cake¡ model was extended to consider effects of bulk density variations within a particular soil type. The anisotropy factor as function of matric potential A(ψ) exhibits different behavior for different soil textures. For example, A(ψ) for sand shows complex behavior with a local maximum just before A(ψ) drops to a minimum where sand becomes isotropic (A(ψ) = 1) near ψ = -1.0 bar Experimentally determined relationships between soil bulk density and hydraulic properties show existence of strong correlation between A(Se) and the ratio of extreme hydraulic conductivity values K(Se) max/K(Se)min for each soil for entire saturation range and across several soil types. The strong dependency of anisotropy factor on extreme values Kmax and Kmin was investigated for four simple and continuous probability density functions of bulk density. Additionally, simple analytical expressions for a binary system of alternating layers with Kmax and Kmin only were derived. An upper bound for A(Se) is obtained with equal weight for K max and Kmin (w = 0.5). The experimental data and model predictions agreed for certain values of weight assigned to either K max or Kmin (∼w = 0.02). Other approximations based on Kmax and Kmin provide simple estimates for anisotropy factor that could be related to shape of statistical distribution of hydraulic conductivity. Copyright 2006 by the American Geophysical Union.

Article no. W12403

פותח על ידי קלירמאש פתרונות בע"מ -
הספר "אוצר וולקני"
אודות
תנאי שימוש
Anisotropy factor of saturated and unsaturated soils
42
Assouline, S., Laboratory of Soil and Environmental Physics, School of Architectural, Civil and Environmental Engineering, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland, Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel, Institute of Soil, Water and Environmental Sciences, ARO, Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel
Or, D., Laboratory of Soil and Environmental Physics, School of Architectural, Civil and Environmental Engineering, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland, Laboratory of Soil and Environmental Physics, School of Architectural, Civil and Environmental Engineering, EPFL, CH-1015 Lausanne, Switzerland
Anisotropy factor of saturated and unsaturated soils
Variations in the degree of anisotropy in soil hydraulic conductivity with changes in water saturation (Se) may adversely impact predictability of flow and transport processes. The conceptual "layered cake¡ model was extended to consider effects of bulk density variations within a particular soil type. The anisotropy factor as function of matric potential A(ψ) exhibits different behavior for different soil textures. For example, A(ψ) for sand shows complex behavior with a local maximum just before A(ψ) drops to a minimum where sand becomes isotropic (A(ψ) = 1) near ψ = -1.0 bar Experimentally determined relationships between soil bulk density and hydraulic properties show existence of strong correlation between A(Se) and the ratio of extreme hydraulic conductivity values K(Se) max/K(Se)min for each soil for entire saturation range and across several soil types. The strong dependency of anisotropy factor on extreme values Kmax and Kmin was investigated for four simple and continuous probability density functions of bulk density. Additionally, simple analytical expressions for a binary system of alternating layers with Kmax and Kmin only were derived. An upper bound for A(Se) is obtained with equal weight for K max and Kmin (w = 0.5). The experimental data and model predictions agreed for certain values of weight assigned to either K max or Kmin (∼w = 0.02). Other approximations based on Kmax and Kmin provide simple estimates for anisotropy factor that could be related to shape of statistical distribution of hydraulic conductivity. Copyright 2006 by the American Geophysical Union.

Article no. W12403

Scientific Publication
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