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Soil compaction is a vital part of the construction process. It is used for support of structural entities such as building foundations, roadways, walkways, and earth retaining structures to name a few. For a given soil type certain properties may deem it more or less desirable to perform adequately for a particular circumstance.
Soil bulk density, when determined at standardized moisture conditions, is an estimate of soil compaction. [3] Soil porosity consists of the void part of the soil volume and is occupied by gases or water. Soil consistency is the ability of soil materials to stick together. Soil temperature and colour are self-defining.
Soil compaction causes reductions in crop growth, yield and quality. Locally, these effects may have minor impacts on food security. If one aggregates the losses in food supply due to soil compaction, however, compaction may threaten food security. This is especially relevant for regions that are prone to droughts and floodings.
The Unified Soil Classification System (USCS) is a soil classification system used in engineering and geology to describe the texture and grain size of a soil. The classification system can be applied to most unconsolidated materials, and is represented by a two-letter symbol. Each letter is described below (with the exception of Pt):
The original Proctor test, ASTM D698 / AASHTO T99, uses a 4-inch-diameter (100 mm) by 4.584-inch-high (116.4 mm) mold which holds 1/30 cubic feet of soil, and calls for compaction of three separate lifts of soil using 25 blows by a 5.5 lb hammer falling 12 inches, for a compactive effort of 12,375 ft-lbf/ft 3.
Dynamic compaction is a method that is used to increase the density of soils when certain subsurface constraints make other methods of soil compaction inappropriate. The process involves dropping a heavy weight repeatedly on the ground at regularly spaced points, usually laid out in a systematic fashion such as a grid.
The pore space of soil contains the liquid and gas phases of soil, i.e., everything but the solid phase that contains mainly minerals of varying sizes as well as organic compounds. In order to understand porosity better a series of equations have been used to express the quantitative interactions between the three phases of soil.
Soil structure describes the arrangement of the solid parts of the soil and of the pore spaces located between them (Marshall & Holmes, 1979). [1] Aggregation is the result of the interaction of soil particles through rearrangement, flocculation and cementation.