ASABE Technical Library - Abstract
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STRESS STRAIN EFFECTS IN STRUCTURED UNSATURATED SOILS ON COUPLED MECHANICAL AND HYDRAULIC PROCESSES
Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.org
Citation: Paper number 021124, 2002 ASAE Annual Meeting . (doi: 10.13031/2013.10376) @2002Authors: Rainer Horn, Christian Albrechts
Keywords: shear stress, precompression stress, strength, hydraulic conductivity, structured soils
The stress strain processes in structured unsaturated arable and forest soils very much depend on
the internal soil strength and on the existing hydraulic and mechanical boundary conditions, which
affect soil deformation by compaction and shearing to a great extent. As soon as the internal soil
strength defined as the precompression stress value is exceeded by external forces, an intense
virgin compression process and in combination with shearing forces at high pore water pressure
values a complete homogenisation of the soil profile down to depth occur.
In situ stresses and strain will be determined by the Stress State transducer System (SST) while the
Displacement of soil particles will be described by the DTS (Displacement Transducer System).
During the determination of the stress strain processes and the shear parameters also the changes
in the pore water pressure and gas exchange must be determined by mini - tensiometers installed
inside the undisturbed soils as the stress and time dependent changes in the compacted and
sheared soil greatly affect the total strength system. Consequently both the hydraulic and the gas
fluxes will be affected by such mechanical properties, which result in an intense alteration of
ecological and mechanical properties of the site. The consequences of such compaction and
shearing on strength and sustainable land use have to be considered with respect to the
sustainability of the system.