To correctly assess the suitability of various types of soils for economic and technical purposes, there is a classification of soils. Guided by it during laboratory, field and geological studies, it is possible to objectively characterize any type of soil and reliably determine the feasibility of its use in one or another quality.
The classification of soils reflects the conditions of their formation, the nature of the origin, as well as the chemical composition, mechanical and physical properties. Of course, the assessment of each individual variety of soil is made on a number of physical characteristics, criteria and characteristics. A huge variety of soils in their composition, structure and condition necessitates the introduction of a large number of different characterizing features, the combination of which is the classification of soils.
All types of soils in accordance with the nature of their structural relationships can be divided into two large categories: rock and non-rock. Within these categories, soil classification provides for subdivision into various groups depending on the origin and nature of the formation. Rocky soils on this basis are divided into igneous and metamorphic. And nekalnye - on sedimentary and artificial origin.
In addition, within each subgroup, a subdivision of soil varieties by various characteristics is also provided. The basis for such a classification may be the physical characteristics of soils, their general chemical or biochemical properties. According to these signs, coarse, silty, clay, biogenic, sandy and other types of soils are distinguished. A more detailed classification is already being made depending on the prevailing mineral composition and particle size, the degree of heterogeneity of the soil and its plasticity, as well as a number of other features.
The classification of clay soils is perhaps the most significant for the design, calculation and construction of various structures. Since such soils are most common. The difference of this type of soil from other classification categories is the stability of their mechanical and water-colloidal structural bonds. Among clay soils, a fairly large number of varieties based on individual indicators of physicochemical and mechanical qualities stand out.
The value of such soils for the construction industry and the national economy is that they are almost the final product of geological evolution and have the best resistance to the natural conditions of the region in which they occur. It is customary to include finely dispersed formations that include at least three percent clay particles and exhibit good plastic qualities and swellability when moistened. These properties are the individual distinguishing features of clay soils.
In accordance with their particle size distribution, they are divided into loam, clay and sandy loam. In general, their main solid component (mineral particles) is a polydisperse system. The mineral composition of such soils is extremely diverse. Often, they are based on particles of quartz and finely dispersed minerals, sometimes various carbonates and rock salt are present in the composition of such soils .