Air and Water Permeability of a Compacted Soil Used in a Solid Waste Landfill in Recife, Brazil

摘要

In terms of SWCC the results are consistent with literature data and show some influence of the initial water content on the initial portion of the curve. It was assumed that these differences do not change significantly with a small change in the compaction energy. This assumption is important for the use of the SWCC in predicting the water permeability function (k(θ)) and the air permeability function (ka(θ)). The water permeability of the soil in its saturated state decreased with the increase in the compaction water content. For the range of water content used, from 12% to 21%, k_w varied approximately one order of magnitude. The air permeability(k_a) measured on the samples showed that when the compaction water content is lower than the optimum, k_a presents only a small change. For values of w/c higher than the optimum there is a reduction in the air permeability of approximately three orders of magnitude. The inflection point is directly associated with the air entry value, that seems to varies from 600kPa to 1200kPa. The Brooks and Corey model was evaluated for the air permeability function. Although there is some variability on the SWCC, affecting the prediction using the model, the result suggested that the B & C model could be a useful tool for predicting the air permeability function. Considering that the experimental determination of the air permeability is much easier than the determination of the unsaturated permeability, the B & C model could be used to predict the unsaturated permeability function.