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If a soil is composed of at least 5 percent of these clay minerals by weight, it could have the ability to shrink and swell. [3] This property is measured using coefficient of linear extensibility (COLE) values. If a soil has a COLE value greater than 0.06, then it can cause structural damage. [2] A COLE value of 0.06 means that 100 inches of ...
Soils with a high content of expansive minerals can form deep cracks in drier seasons or years; such soils are called vertisols. Soils with smectite clay minerals, including montmorillonite and bentonite, have the most dramatic shrink–swell capacity. The mineral make-up of this type of soil is responsible for the moisture retaining capabilities.
Properties that are influenced by soil texture include porosity, permeability, infiltration, shrink-swell rate, water-holding capacity, and susceptibility to erosion. In the illustrated USDA textural classification triangle, the only soil in which neither sand, silt nor clay predominates is called loam .
Distinctions in soils are used in assessing soil which is to have a structure built on them. Soils when wet retain water, and some expand in volume (smectite clay). The amount of expansion is related to the ability of the soil to take in water and its structural make-up (the type of minerals present: clay, silt, or sand). These tests are mainly ...
Vertisols have a high content of expansive clay minerals, many of them belonging to the montmorillonites that form deep cracks in drier seasons or years. In a phenomenon known as argillipedoturbation, alternate shrinking and swelling causes self-ploughing, where the soil material consistently mixes itself, causing some vertisols to have an extremely deep A horizon and no B horizon.
Negative pore pressures in clayey soil can be much more powerful than those in sand. Negative pore pressures explain why clay soils shrink when they dry and swell as they are wetted. The swelling and shrinkage can cause major distress, especially to light structures and roads. [15]
Swelling index may refer to the following material parameters that quantify volume change: Crucible swelling index, also known as free swelling index, in coal assay; Swelling capacity, the amount of a liquid that can be absorbed by a polymer; Shrink–swell capacity in soil mechanics; Unload-reload constant (κ) in critical state soil mechanics
Soil sieve nests with dry soil aggregates after removal from a laboratory drying oven. Soil aggregate stability is a measure of the ability of soil aggregates—soil particles that bind together—to resist breaking apart when exposed to external forces such as water erosion and wind erosion, shrinking and swelling processes, and tillage.