About compaction
Our most labor intense lab. Compaction is the act of reducing the amount of air in a soil by mechanical means, in this case by the use of a hammer. Compaction improves the soil structure by increasing shear strength, increasing soil unit weight, and decreasing settlement. Improving these characteristics of soil becomes fundamental for civil engineering projects. For a given
compactive effort, there is a particular moisture content at which the dry unit weight is the greatest and the
compaction is best. It is our goal in this lab to determine the optimum moisture content, and the associated dry
unit weight for our specific soil type.
compactive effort, there is a particular moisture content at which the dry unit weight is the greatest and the
compaction is best. It is our goal in this lab to determine the optimum moisture content, and the associated dry
unit weight for our specific soil type.
results
Test accuracy
Since the soil is highly organic, values for our compaction test either decreased or increased. This movement from increase to decrease is what caused our compaction curve to be inverted. On a typical compaction curve the sample becomes more dense as the water content is increased. When looking at figure 1, one can see that not even by increasing the water content to 74% do we reach 80% saturation. Table 4 shows typical values of dry unit weight for various soils. Our calculated max dry unit weight was 4.82 kN/m3 which falls right in range for peats and organic silts and clays.