Thursday, November 16, 2006 - 9:40 AM
318-5
Alteration of Soil Structure Geometry Caused by Mechanically Applied Stress and its Consequence on Soil Strength.
The effect of stress application on the alteration of mechanical properties and pore functions is discussed controversially. As long as the applied stress does not exceed the actual soil strength, no further soil deformation occurs. If, however, the actual stress exceeds the internal soil strength, the given elasticity of the platy structure is changed and the smaller pieces will be compressed more intense in a greater soil volume i.e. down to deeper depth. Such deformation can be also derived from the variation in the anisotropy of the precompression stress and cohesion values especially for plough pan layer with the platy structure, which due to the new stress application is changed. The more uniform are the strength values with depth the less harmful is the exceeding stress application e.g. during the sugar beet harvest. The conventionally tilled stagnic luvisol derived from loess with a much more defined plough pan layer and a platy structure down to deeper depth was less stable and the plats were destroyed and new smaller plats formed as compared to the conservation tilled site.
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