HR: 08:30h
AN: H21L-03    [Abstracts]
TI: Evolution of unsaturated hydraulic conductivity of aggregated soils during compression
AU: * Berli, M
EM: markus.berli@dri.edu
AF: Division of Hydraulic Sciences, Desert Research Institute (DRI), 755 E. Flamingo Rd., Las Vegas, NV 89119, United States
AU: Carminati, A
EM: andrea.carminati@ufz.de
AF: Hydrogeology Department, Helmholtz Centre for Environmental Research (UFZ), Permoserstrasse 15, Leipzig, 04318, Germany
AU: Ghezzehei, T A
EM: TAGhezzehei@lbl.gov
AF: Earth Sciences Division, Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Rd., MS 90-1116, Berkeley, CA 94720, United States
AU: Or, D
EM: dani.or@epfl.ch
AF: Laboratory of Soil and Environmental Physics, Ecole Polytechnique Federale de Lausanne (EPFL), Batiment GR 2, Lausanne, CH-1015, Switzerland
AB: Prediction of water flow and transport processes in soils susceptible to structural alteration such as compaction of tilled agricultural lands, or newly constructed landfills rely on accurate description of changes in soil unsaturated hydraulic conductivity. Recent studies have documented the critical impact of aggregate contact characteristics on water flow rates and pathways in unsaturated aggregated soils. We developed an analytical model for aggregate contact size evolution as a basis for quantifying effects of compression on unsaturated hydraulic conductivity of aggregated soil. Relating confined one-dimensional sample strain with aggregate deformation facilitates prediction of the increase in inter-aggregate contact area and concurrent decrease in macro-pore size with degree of sample compression. The hydrologic component of the model predicts unsaturated hydraulic conductivity of a pack of idealized aggregates (spheres) based on contact size and saturation conditions under prescribed sample deformation. Calculated contact areas and hydraulic conductivity for pairs of aggregates agreed surprisingly well with measured values, determined from compaction experiments employing Neutron- as well as X-ray-radiography and image analysis.
DE: 1822 Geomechanics
DE: 1835 Hydrogeophysics
DE: 1847 Modeling
DE: 1866 Soil moisture
DE: 1875 Vadose zone
SC: Hydrology [H]
MN: 2007 Fall Meeting