Soils

Particle Size Distribution: well graded or uniformly graded soil, Uniform soil or poorly graded soil and Gap graded or skip graded soil Moisture Content (W) : It is the ratio of weight of water to the weight of solid in given mass of soil. Agents that Transport Soil: Wind, Gravity, Water and Ice Liquid Limit: It refers to the water content at which the soil changes from the liquid state to plastic state. Plastic Limit: It is the water content at which the soil becomes semi-solid. Shrinkage Limit: It is the water content at which the soil changes from semi-solid state to solid state. It is also lowest water content at which the soil is fully saturated. Plasticity Index = (Liquid Limit - Plastic limit), Shrinkage Index = (Plastic Limit - Shrinkage Limit), Liquidity Index = (Water content - Plastic Limit)/(plasticity Index), Relative Consistency=(Liquid Limit- water content)/(plasticity Index)and Activity Ratio = (Plasticity Index / Clay fraction). Compaction: Compaction is the densification of soils by the application of mechanical energy. It may involve a modification of the water content as well as the gradation of soil. * The fundamental of compaction of cohesive soils are relatively new R.R. Proctor in the early 1930`s was building dams for the old Bureau of waterworks and supply in Los Angeles, and he developed the principles of compaction in a series of articles in engineering News-record(Proctor 1933). In his honor, the standard laboratory compaction test which he developed is commonly called the Proctor test. Compaction is afunction of four variables: (1) Dry density (2) Water content (3) Compactive effort (4) Soil type (Gradation, presence of clay minerals etc.)