Soil compaction level, excluding the characteristics of soil texture and degree of soil moisture, was identified by soil relative density (DR) (BEUTLER et al., 2005), which is the quotient of DS with its Dsmax, drawn from Proctor's essay.
From the equation of the compaction curve of the normal Proctor assay, mathematically it is easy to derive the Dsmax and optimal humidity for compaction.
However, for silt soils, this equation poses difficulties as it over estimates the Dsmax in such soils; this occurs because the silt content is excluded from the calculation, which fraction is evident in greater amounts in silt soils.
The first derivative of the function enables the optimal compaction humidity (UOC) to be estimated, while the second helps to determine the Dsmax. Relative density was calculated by the quotient between the DS and Dsmax.
Determination indices higher than 0.77 were noted, which clearly described the Dsmax phenomenon in these soils.
The rise in the silt concentration (Figure 1c) caused the maximum density values to drop; although, the clay and the clay plus silt did not reveal any notable influence on the Dsmax. These results differed from the findings of MARCOLIN & KLEIN (2011), in their research on the Latosols.
Calibrated Number Parameters Definition value 1 B Variable infiltration curve 0.236 parameter (binfilt) 2 Ws Fraction of maximum soil moisture 0.533 where nonlinear baseflow occurs 3 Ds Fraction of Dsmax
where nonlinear 0.481 baseflow begins 4 Dsmax
Maximum velocity of baseflow 13.748 5 d0 0.300 6 dl Thickness of each soil moisture 2.430 layer 7 d2 0.533
No entanto, conforme se adiciona agua a forca de adsorcao das particulas do solo pelas moleculas de agua diminui, facilitando a compressao do solo, ate atingir a Dsmax
de compactacao em virtude da expulsao de ar dos vazios do solo ocorrendo, a partir deste ponto, um processo inverso em razao da fluidez e incompressibilidade da agua.