Estimation of the structural conditionby physicomechanics methods

The works, devoted studying of resistance of soil to loadings has some, thus there isno uniform system of the characteristics of strength, that very much complicates comparisonof the data received by different authors. Besides the overwhelming part of experimentsis spent on prepared samples though not deformed unit can have absolutelyothers characteristics of strength.In given article properties of structure of soils are considered, being based on property ofmechanical strength of units and the opportunity of the characteristics of mechanical strengthof the unit is proved by surface energy of the solid phase defined on heat of wetting. As objectsof research 7 samples of soils with various characteristics of strength have been chosen. Mechanicalstrength was defined by a method conic Rebinders plastometer.By consideration of sizes of strength of air-dry units in an investigated line of soils thetendency to increase in strength from sod-podzolic soils to chernozems is visible explainablethe surface phenomena. Also strength increases downwards on a profile in illuvialed and degradedsoils, and decreases in not disturbed and low-disturbed chernozem. In the first case itis caused by washing away of silt particles and a humus in underlaying horizons, in the secondpresence of a plenty of a humus and a high specific surface in the top horizons. Thus, mechanicalstrength of units - function of a surface of soil that unites influence of a specific surface,the content of a humus, silt, exchange cations and many other things of parameters.A parameter of surface energy which size unites all the listed factors, heat of wetting whichcharacterizes a molecular-ionic level of the structural organization of soils is. Values of heatof wetting in an researched line of soils increase from sod-podzolic soil to chernozems in parallelwith increase in a specific surface. The specific heat of wetting describing quality of asurface, changes depending on the content of a humus.Under influence of agricultural loading in soil there are irreversible changes of asurface. Reduction of a specific surface in a line of soils chernozem virgin- ploughedfield - «timeless» fallow, so also activity of a surface reduction in heat of wetting andhydrophilia is natural.From this follows, that heat of wetting is the proved and convenient size for the characteristicsboth surface energy of soil, and mechanical strength as functions of thispower condition. The further research of a ratio of these sizes is a perspective directionphysicomechanics of soils.

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