Perm Journal of Petroleum and Mining Engineering (Jun 2019)
Alteration in composition of clays subjected to man-made impact Alvanya
Abstract
Physical and chemical properties of clays depend on a group of factors determining energy potential on particle surface and on factors forming particle specific surface. Particle specific surface formation is directly related to issues of microaggregates formation in soil. Studies of influence of pressure in aggregates formation in dispersive soils showed that at pressure up to 200 MPa slight alteration in aggregate composition is observed in wet soils. At pressure 300 MPa in powdery soil content of thin sandy fraction increased from 13 to 51 %, powdery fraction – from 5 to 23 %, and clay fraction – from 2,15 to 5,42 %. During test of covering loams with pressure Р =2000 MPa and Р =3 660 MPa similar results were received. From the stated above it follows that issue of pressure influence on formation of microaggregate composition and, as result, physical and chemical properties of clay are of substantial interest. Regularities in alteration of composition of clays subjected to high pressure were studied. As result of experimental studies, it is established that along with pressure increase general tendency of reduction of clay fraction content and increase of powdery fraction content is observed. Together with this regularity, local alterations of clay fractional composition depending on pressure in each class are found. Along with pressure increase, particle specific surface value of kaolin and montmorillonite clays reduces. Alterations in granulometric composition are determined by particle aggregation and dispergation processes. During aggregation process caused by high pressure coagulation, transition and phase contacts between particles are formed. Breaking and wedging pressure of adhesive water film around particles are leading factors determining process of their dispergation.
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