Changes in the rheological properties and bulk density of soddy-podzolic soils under dynamic loads

Abstract

Field studies of the rheological properties of loamy sandy soddy-podzolic soils were performed. Within the studied ranges of the soil moistening and bulk density values, the soils behaved as viscoelastic bodies. The dynamic deformation of such soils under compressive stress was modeled by a differential equation of the first order linking the compressive stress, the rate of its changes, and the relative soil deformation in the vertical direction. Correlative relationships between the viscoelastic soil properties, the soil bulk density, the soil water content, and the angular frequency of the harmonic law of the soil deformation were obtained. The methods of calculation of the soil bulk density as dependent on the initial bulk density and the mode of the soil deformation upon cyclic loads by rigid cylinders and by elastic wheels were developed. These methods were realized in a computer program for the quantitative assessment of the effect of the major factors on the changes in the rheological properties, the indices of the soil deformation, and the soil bulk density under the impact of compressive loads. It was shown that an increase in the number of loading-unloading cycles leads to the transformation of the viscoelastic soil properties into elastic properties.