Soil softness - the ability of rocky and semi-rocky soils to reduce their strength when interacting with water. One of the characteristics of water resistance of soils .
Softening nature of soils
The softening mechanism, as well as the softening of soils, consists in weakening the structural bonds between particles, grains, crystals due to the penetration of water molecules into the gaps between them and reducing the surface energy of the system. It is based on the so-called Rebinder effect - an adsorption decrease in the strength of solids. Water molecules, adsorbed on the surface of solid soil components, penetrating microcracks and micropores , cause proppant pressure, which leads to the growth of cracks, defects and a decrease in the strength of the soil as a whole.
Liquids and aqueous solutions that do not cause the Rebinder effect do not affect the strength of the soil. These include, in particular, some non-polar liquids (liquid hydrocarbons , etc.).
Softness indicators
The softening factor is the softening factor (k sof ) - the ratio of the ultimate tensile strength of the soil to uniaxial compression, respectively, in water-saturated (R cr w ) and air-dry (R cr ) states: k sof = R cr w / R cr . The higher the k sof value, which varies from 0 to 1, the less softened is the soil. In accordance with SNiP 2.02.01-83 *, rocky soils are divided into two categories: softened (k sof <0.75) and non-softened (k sof ≥ 0.75).
Literature
- Soil Science / Textbook. Ed. V.T. Trofimova, 6th ed. M.: Publishing House of Moscow State University, 2005, 1024 pp.
- Korolev V. A. Soil water resistance / Russian Geological Encyclopedia. In three volumes. Volume 1 (AI). - M. - St. Petersburg: VSEGEI Publishing House, 2010. S. 211-212
- Basic concepts of engineering geology and environmental geology: 280 basic terms./ Ed. V.T. Trofimova. - M., JSC Geomarketing, 2012, 320 p.