Void Changes in Allophane Soils Determining Water Retention and Transmission
1975
Maeda, T. | Warkentin, B. P.
Water retention and transmission were measured on eight samples of allophane soils from the West Indies and Japan. Standard methods of pressure plate, horizontal infiltration and steady-state horizontal flux were used. Soils with high allophane content have a sigmoid water content vs. log suction curve. Drying does not change the shape of the curve, but decreases the water content at any suction. Soils with low allophane content show a more linear water content vs. log suction curve, resembling that of clay soils with crystalline minerals. Water transmission in undried allophane soils is slow because of the high proportion of microvoids. Air-dried or oven-dried samples have a higher proportion of macrovoids, and more rapid infiltration of water. This change in void size distribution is large enough to dominate the effect of greater volume of voids to be filled with water in an initially dry soil, with the result that water movement in allophanes increases as initial water content decreases.
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