The effect of stress distribution in soils with different moisture content applied during harvesting under forest was determined on a sandy loam Alfisol, in the Coastal Mountains, Yumbel, Chile. Transducers inserted in the soil were used to determine stress distribution. Concentration factor, pore size distribution, bearing capacity and internal cohesion was determined on wheels tracts and inalterate sites. The soil can either react more or less stable, according to moisture contento The greatest changes were on pore system under wet conditions. When dry, compaction is very low, but with a tendency to pore distribution changes. Bearing capacity and internal cohesion decrease slowly. The concentration factor is < 3, and the pressure bulb shown a horizontal orientation. The greatest settlement with 120 mm from a original soil column of 750 mm occur bywheeling in spring, morethan 54% of coarse pore volume was lost. Internal cohesion and bearing capacity increased on 45% in the compacted soil under this condition. The penetration of pressure bulb was vertical with a concentration factor ≡5. The results support the idea that each wheeling has to be limited to periods where the stress attenuation in the soil is capable to resist applied external forces. |
ChileanJAR
