THE EFFECT OF SOIL AGGREGATION ON STRESS-DISTRIBUTION IN STRUCTURED SOILS

The mechanical compressibility of arable soils can be described by preconsolidation load value and by the shear resistance parameters of the bulk soil and single aggregates. In order to quantify the effective stress equation must be also known the hydraulic properties of the soil in dependence of the intensity, kind, and number of loading events. The soil reacts as a rigid body at very fast wheeling speed inclusive a very pronounced stress attenuation in the top soil while stresses will be distributed in the soil threedimensionally to deeper depths at slower speed. These variations can be explained by the mechanical as well as by the hydraulic parameters of the bulk soil and single aggregates. Thus, the pore water pressure value of the bulk soil as a parameter of the effective stress equation further depends on the hydraulic properties of the inter- and intraaggregate pore system and continuity. As can be derived from the results the pore water pressure values are identical irrespective of the predessication for clayey polyhedres at high load while in coarse textured prisms the pore water pressure value depends on load and predryness. The consequences for soil strength under dynamic loading are shortly discussed.