chapter  3
34 Pages

Refraction of Water Flow in Soils

I. Refraction of Flux......................................................... 90 II. Theory of Refraction of Flux ........................................ 90

III. Jump Condition ............................................................ 94 IV. Visualization of Refractional Water Flow

in Layered Soils............................................................ 96 V. Verification of Refraction Theory............................... 101

A. Experimental Verification ................................... 101 B. Verification of a Numerical Method.................... 103

VI. Refraction and Anisotropy Coefficient....................... 105 A. Anisotropy Coefficient in Saturated

Layered Soils ....................................................... 105 B. Anisotropy Coefficient in Unsaturated

Layered Soils ....................................................... 107 C. Refractive Anisotropy Coefficient ....................... 108

1. Two-Layer Model.......................................... 108 2. Multilayer Model........................................... 111

Appendix: The Jump Condition and the Finite Element Method .............................................................. 115

References............................................................................ 120

I. REFRACTION OF FLUX

Fluxes of water in soils change their magnitudes and directions depending on spatial variability of the hydraulic properties of soils. When hydraulic properties vary continuously with position in soils, the directions of streamlines may be curved. When hydraulic properties vary discontinuously with position in soils, the streamlines may be refracted at the boundaries between regions of different hydraulic properties. These curvings and refractions of streamlines occur not only in saturated soils but also in unsaturated soils. In layered soils, for example, both saturated and unsaturated hydraulic conductivities are usually different in each layer (1), resulting in refractions of fluxes of water at the boundaries of the layers.