INFLUENCE OF PRESSURE ON THE ACTIVE SURFACE AREA OF CLAY SOIL PARTICLES

Abstract

The authors of this paper have established that, with increasing pressure on clay soil, it is observed a general tendency for the content of the clay fraction to decrease and for the share of the silty fraction to increase. These changes are more intensive in montmorillonite clay, than in kaolinite clay. The changes in the fractional composition of clays are more intensive under pressures of 0–125 MPa, than under pressures of 125–750 and 800–2 200 MPa. With increasing pressure, the active surface area of particles of both kaolinite and montmorillonite clays is decreasing. At that, the maximum rate of this decrease is observed under pressures of not more than 125 MPa. Under pressures of more than 125 MPa, the influence of pressure on the active surface area of particles is less significant. The authors have developed mathematical models that allow predicting the active surface area of clay particles, depending on the compression degree of these soils.