HR: 1330h
AN: H32A-0512    [PDF]
TI: 3D MRI Visualization of the Infiltration Outflow Experiment
AU: * Cislerova, M
EM: cislerova@fsv.cvut.cz
AF: Czech Technical University in Prague, Faculty of Civil Engineering, Thakurova 7, Prague, 166 29 Czech Republic
AU: Snehota, M
EM: snehota@mat.fsv.cvut.cz
AF: Czech Technical University in Prague, Faculty of Civil Engineering, Thakurova 7, Prague, 166 29 Czech Republic
AU: Amin, G M
EM: mhga1@hslmc.cam.ac.uk
AF: HSLMC University of Cambridge, University Forvie Site, Robinson Way, Cambridge, CB2 2PZ United Kingdom
AU: Hall, L D
EM: ldh11@hslmc.cam.ac.uk
AF: HSLMC University of Cambridge, University Forvie Site, Robinson Way, Cambridge, CB2 2PZ United Kingdom
AB: An automated experimental setup was built up to measure the flow of water through the soil sample located within the Magnetic Resonance (MR) scanner. A modified disc infiltrometer was used to adjust the boundary condition at the top of the sample. Free outflow was used as the bottom boundary condition. Pressure head was measured by tensiometer installed in the body of the sample. Values of hydraulic pressure head and cumulative flow data were recorded in time. Recurrent ponded infiltration-outflow and tension infiltration-outflow experiments were applied to two undisturbed samples (9 cm diameter, 8.5 cm height) of coarse sandy loam (Korkusova Hut, CZE). Water distribution within the samples during RPI was monitored using MR Imaging. Spin-echo protocol was used. The multiple slice horizontal 2D imaging was done during the steady state flow and during the equilibrium after drainage. The complete set of 2D images forms the 3D image of the soil core for each particular run. Also 3D matrices of MR parameters, namely signal intensity M and relaxation constant T1 were measured to evaluate the validity of MR signal of each voxel. Beside that, the internal structure of the soil cores was visualized by X-ray Computed Tomography. Preferential flow and a decrease of the steady-state infiltration rate between two successive infiltrations of RPI are typical for the soil studied. In this soil under near-saturation condition, significant preferential flow and initial-saturation dependent hydraulic properties have been regularly observed. It is hypothesized that the instable behaviour is mainly due to the air phase present within the sample. Data are used for evaluation of hydraulic characteristics for the dual permeability simulation model.
DE: 1875 Unsaturated zone
SC: Hydrology [H]
MN: 2003 Fall Meeting