THE INFLUENCE OF CAPILLARY FORCES ON THE STRENGTH OF CLAY SOILS 

F. S. Karpenko*, V. N. Kutergin, S. I. Frolov, O. V. Serebrova

Sergeev Institute of Environmental Geoscience, Russian Academy of Science, Ulanskii per., 13, bld. 2, Moscow, 101000 Russia

*E-mail: kafs08@bk.ru

Capillary forces operating in incompletely water-saturated clay soils appear to be an important agent affecting their strength properties. The paper considers the results of practical studies in the changing value of capillary compressive forces in clay soil varieties depending on their water saturation degree. Investigations are based on the physicochemical strength theory. It is shown that the value of capillary compressive forces in clays depends on their structure, the prevailing type of structural contacts, the number of clay particles and contacts between them. This value is proved to be dependent on the degree of water saturation in soil, changing regularly with the variation of the latter.

Keywords: clay soils, structural contacts, general effective stresses, actual effective stresses, capillary meniscus, capillary compressive forces

REFERENCES

1. Lomtadze, V.D. Izmemenie sostava, struktury, plotnosti i svyaznosti glin pri uplotnenii ikh bol’shimi nagruzkami [Changes in the composition, structure, density and cohesion of clays compacted under heavy load]. Trudy laboratorii gidrogeologicheskikh problem AN SSSR. 1955, vol. 12. (in Russian)
2. Karpenko, F.S., Kutergin, V.N., Kalbergenov, R.G. Vliyanie rasklinivayushchego deistviya gidratnykh plenok na prochnostnye svoistva glinistykh gruntov [Influence of the disjoining effect of hydrate films on the strength properties of clay soils]. Geoekologiya, 2018, no. 4, pp. 91-97. (in Russian)
3. Karpenko, F.S. Fiziko-khimicheskaya priroda predelov plastichnosti glinistykh gruntov [Physicochemical nature of clayey soil plasticity limits]. Geoekologiya, 2018, no. 5, pp. 66-72. (in Russian)
4. Karpenko, F.S. Fiziko-khimicheskaya priroda prochnosti glinistykh gruntov [Physicochemical nature of clayey soil strength]. Geoekologiya, 2019, no. 5, pp. 48-60. (in Russian)
5. Osipov, V.I. Fiziko-khimicheskaya teoriya effektivnykh napryazhenii v gruntakh [Physicochemical theory of effective stresses in soils]. Moscow, IFZ RAN. 2012, 74 p. (in Russian).
6. Osipov, V.I., Sokolov, V.N. Gliny i ikh svoystva. Sostav, stroyeniye i formirovanie svoystv [Clays and their properties. Composition, structure and formation of properties]. Moscow, GEOS Publ. 2013. 576 p. (in Russian)
7. Sergeev, E.M. K voprosy o mekhanicheskoi prochnosti dispersnykh gruntov [On the issue of mechanical strength of fine soils]. Uch. zapiski MGU, 1949, no. 10.
8. Sokolov, V.N. Vliyanie vlazhnosti na prochnost’ strukturnykh svyazei glinistykh chastits [Moisture effect on the strength of structural bonds between clay particles]. Vestnik Moskovskogo Universiteta. Ser. 4. Geolog. 1973, no. 6, pp. 100-104. (in Russian).
9. Sokolov V.N., Osipov V.I. Vliyanie razlichnykh kategorii svyazannoi vody na prochnost’ glin [Influence of different categories of bound water on clay strength]. Svyazannaya voda v dispersnykh sistemakh [Bound water in disperse systems], Moscow, MGU Publ., 1977, iss. 4, pp. 4-15. (in Russian)
10. Filatov, M.M. O mikrostrukture gruntov v svyazi s deformatsiyami ikh pod vliyaniem nagruzki [On the microstructure of soils in connection with their deformations under load]. Fizika pochv SSSR. Trudy Sov. sektsii Mezhdunarodnoi assotsiatsii pochvovedov. 1936, vol. 5.